scow bow cruising sailboat

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CRUISER-RACER CONFUSION: Scow Bow Revolution 29 and Gunboat G4 Capsize

This is something I ask myself quite often: can a modern truly cutting-edge high-performance racing sailboat also be a cruising boat? In certain ways, of course, the old ideal of the true cruiser-racer, per the glory days of the Cruising Club of America rating rule and boats such as Carleton Mitchell’s famous yawl Finisterre , evaporated many decades ago. Yet still it is an ideal that both boatbuilders and boat owners incessantly aspire to somehow realize in a modern context, and it is fascinating to watch how these aspirations manifest themselves. Take, for example, the Revolution 29 (see image up top), a new cruising design developed in France that is directly based on David Raison’s radical scow-bowed Mini 6.5 in which he won the Mini Transat in 2011.

Raison’s Mini was not just radical in appearance; it was radically fast and won the 2011 Transat by a large delta, setting a new course record in the process. This success was so significant that other important monohull racing classes—Open 60s, Class 40s, TP 52s—pretty quickly banned scow bows for fear their existing fleets would instantly be rendered obsolete. Development of the concept continues however within the Mini class, which has long been a leading hotbed of high-performance monohull sailing innovation.

David Raison arrives in Brazil aboard TeamWork Evolution in 2011 after crushing the rest of the Mini fleet

What’s interesting about the scow bow, of course, is that it is one of those few racing innovations that immediately and obviously has critical advantages in the cruising market. As in: if you make the bow of any boat much wider you have lots more space inside for accommodations.

Interior of the Revolution 29. A whole lot of space for a boat this small. Note there is also a predecessor design, the Revolution 22, more directly based on the 22-foot racing Mini

But putting a scow bow on a cruising boat obviously doesn’t instantly make it a “cruiser-racer.” What makes the scow bow super-competitive is that it facilitates a boat’s ability to plane, and the other key factor in that equation is always weight. Or rather the lack of it. Load up a boat with lots of furniture and gear and you will seriously inhibit its ability to plane regardless of what shape its bow is. As always, a certain balance must be achieved and compromises must be made.

To get an idea of what a competitive scow-bow boat looks like under sail, watch this viddy here of TeamWork Evolution drag-racing against a conventional Mini.

You should note in particular the boat’s insanely huge sail plan. Prototype Minis are renowned for these, and obviously the rig on any reasonable cruising boat would want to be quite a bit smaller. One question in my mind is whether you in fact need all the extra sail area to make the scow bow fast. Could it be that with more cruiser-sized sails the scow bow might actually be slower than a conventional bow?

The new G4 does its flying thing

Another question being openly discussed right now, thanks to Gunboat and its new G4 foiling catamaran , is whether foils make any sense on a “cruiser-racer.” As I mentioned in my previous post on the boat, it is the first fully foiling boat with any sort of accommodations, and Gunboat has been marketing it as a coastal cruiser-racer. And now in its racing debut at St. Bart’s the svelte little beast has capsized in dramatic fashion, which has prompted some forum trolls as well as a few otherwise polite people to wonder out loud how this could possibly be termed a cruising boat.

Wipe Out from Gunboat on Vimeo .

Watch the viddy here first and then ask yourself: did the boat capsize because it was foiling, or did it capsize because the crew was unable to release the mainsheet for some reason? To me it definitely looks like the latter and that this would have happened, given the issue with the sheet, to any performance cat whether it was airborne or not.

Actually in this image it looks like that helicopter might have been a precipitating cause

Gunboat CEO Peter Johnstone, post flip

So maybe we shouldn’t be focussing on the foils so much. After all, as I understand it the G4 was originally developed as a straight performance cat and the flying foils were added later in the process. Like the AC72s in the last America’s Cup go-round, the G4 wasn’t born a foiler, but evolved into one. Also, of course, it is perfectly obvious that the boat capsized because it was being raced and not cruised. The crew was pushing the boat to its limits, and just because it has a limit (like any boat) doesn’t mean it can’t be cruised. For example, I have a friend who once owned a heavy full-keeled Tayana 37 that was dismasted during a distance race because he declined to take his spinnaker down when conditions got strong. The spinnaker in a gust just pulled the mast right off the boat. Which obviously doesn’t mean you can’t go cruising in a Tayana 37.

I think the real question to ask is: is there a point at which a boat becomes too performance-oriented to really be termed a cruiser? Which really is just another way of asking: what exactly is a cruiser-racer?

Back in the days of Carleton Mitchell and the very conservative CCA rule it was a pretty simple concept. A cruiser-racer was a boat designed to cruise that you could also race, and basically all you had to do to do that was take a ton of crap off the boat and—if you were very serious—bend on different sails. Back in those salad days, that was all it took to be competitive at the highest levels of racing.

These days there are many more variations of the species. There is a vast universe of older boats racing mostly under the PHRF rule in local beer-can series that are very obviously cruising boats that are being raced just for fun. We have a few what I call “captive venues,” the best example being Swans, where there is a small universe of very active racing focussed usually around a brand, where an honest-to-God cruising boat can engage in some pretty serious racing with other cruising boats. We have fancy expensive “performance cruisers” with luxurious interiors that can be raced if desired with minimal changes to the boat (this is pretty much the category the larger Gunboat cats fall into). We have a few even more insanely expensive performance cruisers with wholly interchangeable interiors for both cruising and racing. (I have even seen boats with interchangeable keels!) We have various folding trimarans with cramped accommodations that can be raced in various events. We have families with small children cruising around the world in modified open-class ocean racers. We have “buckets” where enormous super-yachts, obviously designed for cruising in the most obscenely opulent sense of the term, can race against each other.

And on and on and on. The market for sailboats that can be both raced and cruised has become so complex and variegated it is impossible to say where it begins and ends.

Really the only advice I can give to help make sense of this spectrum is that the terms “cruiser-racer” and “racer-cruiser” should not be used interchangeably. Rather we should agree on two specific definitions. As in a cruiser-racer is a boat designed to cruise that can also be raced, and a racer-cruiser is a boat designed to race that can also be cruised.

The G4 I think is certainly a racer-cruiser, and perhaps to some it is an extreme example, but I for one would be very happy taking it out for a week’s worth of high-octane gunkholing.

IN OTHER DEVELOPMENTS: There’s some buzz on the Sailing Anarchy forums that the Gunboat 55 Rainmaker , abandoned after being dismasted back in January , has been spotted again, afloat, but with her coachroof torn away (remember, this is an open-bridgedeck boat, the roof is merely shelter). There’s even one guy claiming the boat has been towed in somewhere, but so far there’s no confirmation of this. I have heard confirmation of the boat’s being spotted, and of the damaged coachroof, from the boat’s designer Nigel Irens via third parties.

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The scow bow helps the boat surf, especially sailing off the wind. But how is it beating into steep seas?

@Damon: That is the question, for sure. Even if it’s still fast to windward, I bet it’s not exactly comfortable. One advantage of the shape is the waterline area is likely very symmetrical when the boat is heeled, but I guess the bow must pound something fierce.

I think the answer to your question is, yes.

This type of fast – cruising, would be different than what cruising has evolved into since the Finessterre days.

Today, cruising can mean a life choice/commitment of living for decades on a sailboat. The cruising sailboat that must serve as a home at sea has evolved into a complicated and commodious(and expensive), vessel.

To cruise in a high performance boats like you’ve posted, means going light. Backpacking as compared to RV-ing. The speed could be a whole new adventure and lure for younger sailors. But it will come at a cost of comfort and maybe will become less of a time commitment, as back packing is(not many backpack open-ended, for decades).

It appears less people today are jumping into the life choice cruising mantra of the 60’s and 70’s. Yet sailing is as popular as ever with young and old(around me).

I see this notion of a lighter, smaller, faster(cheaper), sailboat on a ‘sail’, as having appeal to a new generation of sailors my kids(and their friends) age, as they grow into a life(and the means), that includes sailing.

Speed is good and will take skill to tame(I love 4kts)!

I have cruised and raced my light, go fast boat for 25 years, loved every minute.

I am drawing a 42′ idea, 14′ beam, looking at 10-12 as a good speed for us elders (me 69, she 66). assy lee boards, unstayed rig, two winches, lots of hatches and deck openings. I built an Atkin Ingrid in 1969-74 and sailed her from San Fran to NZ. As a sailmaker who raced 5O5 at WC level for awhile, the slowness and poor performance upwind of that double ender shape was always tough to trade for some speed. not to mention low and wet. When i hitched a ride from Tahiti to Maui on a Cal 39 it really showed me how nice the speed could be for comfort as well. Better wave synch etc.

thirty years of windsurfing speed and early foiling tri’ experience (Longshot) leave a deep impression about how fast we can go… but 10-12 will do for this stage of my ocean travel dreams. plus, samantha isn’t comfortable with the whole concept yet. got to make it comfy. our Westsail 42 is growing on her, and she’s getting used to that scale of living aboard .

thus, i’d love to hear from anyone who has had some experience with these shapes in head seas. i’m right there with the french concept. so happy to let them find out these things before my paper becomes a boat.

bob johnstone sailed the grot baer across oceans. he probably wasn’t in a hurry. but he must have been comfy enough. if you are truly voyaging, and not sight seeing on a plan, you rarely need to go to weather. it’s a choice. you just have to be flexible about destination and time, no schedules. with today’s weather magic on the net there is even more choice of routing underway for comfort… as long as you are more about the voyage than the destination. obviously i approve of aimless wandering… and have a wife who loves the easy sailing, hates the other bit, and is willing to just be out there,

if that is what it takes to bring her on board happily, i’m on with it. it’s all a bunch of compromises, for senior citizens like us to be voyaging viable for another bunch of years, then end up in freemantle or perth with a nice liveaboard until you can’t get up/down/in/out, that suits us.

i expect our vessel will sail very well. a good compromise.

and that pounding thing. i see mushy pushing, throwing the spray off. the slab side forward when heeled? might that pound? i busted the bow bulkheads out of a ranger 37 pounding to weather. once. maybe mushing is better.

i really am imagining all of it more and more. hope to feel the water doing whatever it wants ASAP.

I was watching the wave action and the helmsman action. He did the right thing to release the main but it was not enough. Secondly the person responsible for the genoa sheet was pulling in when he should release. It does appear that the chopper is the culprit to give them dirty air washed down from the blades. Lastly why is it that not a single one was wearing lifejacket in this kind of boat. It is a different class of sailing and may not appeal to some mundane sailors but is it such fun to the adventurous types. Keep it up!

I think anyone who’s ever noticed the sink and wood trimmed mirror down below in a J 24 knows the Johnstone’s tendency to put accomodations into boats which aren’t really safe to cruise in.

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Giancarlo Pedote rounded bow

Scow bows – more righting moment and better downwind speed

When the Mini Transat sent out a media release about some new designs for this year's race, we looked at the ugly scow bow in the picture and asked “why?”. Fortunatey, our readers include designers and naval architects, some of whom replied.

Dario Valenza is Australian Sailing + Yachting 's technical contributor and runs Carbonic Boats, which makes an interesting A Class and also produces other high-tech design elements. See more at  www.carbonicboats.com . Dario writes:

The short answer is more righting moment, both across the boat and longitudinally. For a given overall beam and keel weight, a scow bow gives more volume away from the centreline as well as more volume ahead of the centre of gravity.

Instead of only having outboard volume from the middle of the boat to the transom as on a pointy boat, with a scow you have it all the way along. This means that the centre of buoyancy moves outboard further when you heel, giving a higher metacentre, or more leverage for the keel and boat mass to exert righting moment.

If sail area is unrestricted, more righting moment means you can carry more sail for a given windspeed. Similarly, downwind you can press harder without burying the nose.

The above only considers hydrostatics. When you look at the dynamic situation, the scow also gives more planing area. But this is secondary since ordinary Minis had no problem planing. Maybe a scow can plane a bit sooner.

Another secondary advantage is that you have more volume for water ballast.

I am not up to speed with the Mini rules, but if they have a static heel limit with ballast loaded, then a scow will get more righting moment from a similar water ballast arrangement to a conventional peer.

The clever thing about a scow is that it obtains the extra righting moment without big changes in trim with heel. You don't get the tendency that wedge-shaped boats have to trim bow-down when heeled. Though recent progress in chined hull design has helped deal pretty effectively with the warping of the waterplane with heel, scows don't have to deal with it at all.

Which brings us to the downsides. The single biggest handicap is additional wetted area when upright. Once powered up the waterline gets narrower, but at zero heel you have a canoe body with disproportionately wide and shallow sections.

A conventional boat can shift weight forward to unstick the transom. A scow is harder to trim and does not have the narrow forward sections of a conventional hull.

Also the blunt bow does give more resistance in some wave conditions and more windage when sailing upwind. Some consideration must also be given to the fact that the keel root is very close to the surface when heeled. Finally, a scow hull uses more material than a conventional one so it will be stiffer but heavier.

In the end the outcome is in great part rule-dependent. The Mini is a short light boat with unrestricted sail area, so adding righting moment usually pays because it allows you to carry more canvas. Some of the extra sail area offsets any drag penalty paid for the extra righting moment. The rest is a net gain.

Another consideration is that with good weather routing, most time on the course can be spent sailing downwind in breeze where the drawbacks of the scow are smaller.

You might be interested to know that RC 10 Raters went through a scow 'trend' in (I think) the 1970s. Possibly around the time the Moths did. http://www.radiosailing.org.au/our past/Frank Russell.pdf . Notably the 10 Rater rule allows you to trade waterline length for sail area.

Also interesting is that the 10 Raters could get away with very low freeboard like the lake scows, but for a different reason: The lake scows sail mainly in flat water but the 10 Raters had no crew to keep dry. 

– Dario Valenza 

Naval architect Andy Warner also sent us a succinct explanation of the positives for a scow bow:

With a displacement hull the angle that the water is parted with at the bow is an important contributor to resistance of the form along with Displacement, Length, Prismatic Coefficient, position of the Centre of Buoyancy. The bigger the angle the more resistance.

If the hull is not operating at displacement speeds but rather is planing the resistance of the form is governed by a different set of factors. Particularly Length and bow angle are much less of a contributor and beam plays a bigger role. Look at a picture of a powerboat on a plane with the narrower bow lifted clear of the water and a much blunter part just throwing water out to the side.

The boat you have a picture of for the mini transat clearly expects to be planing most of the time.

Likewise if the Sydney Hobart was a race with boats planing from start to finish Comanche would have won but when the wind went a bit lighter or on the nose the narrower Wild Oats had the advantage. Every boat design is a compromise and a balancing act. Extreme boats will always win if they get the right weather

– Andy Warner

And Hugh Spencer contributed these thoughts:

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Revolution 29

A unique scow bow makes the revolution 29 spacious and fast.

We are going to have some fun this month—there is an interesting trio of boats to review. I don’t know if you have been following the MiniTransat class ocean racers but you should. These little pocket rockets are amazing boats, very extreme and capable of high speeds in the hands of skilled crew. The class is growing rapidly, especially in Europe. Minis use a box-type rule that limits LOA to 21 feet 4 inches, so designers have to look for innovative ways to gain sailing length and power. 

Enter the scow bow Minis. At first look I was inclined to think, “Oh God, please don’t make this fast.” But I knew that scow bows have a long and successful history so the chances were strong that this bow would work. It works on the many scow one-design classes and even the old, sedate, CCA rule had Hoot Mon, a scowlike yawl with a successful race record. 

It was inevitable that a builder would jump on the scow bow for a family cruising boat. Look at that beam and volume forward. Along came Afep Marine with designer David Raison. Together they have produced the aluminum Revolution 29, along with its 21-foot little sister. It’s funny looking; there’s just no way around that. The ends are snubbed off, there is zero spring to the sheer and the only attractive line I can find on the entire hull is the chine that runs around the bow.

I suspect that the heeled waterlines for this hull would look fairly normal with that chine making a somewhat V-shaped entry. Using 27 feet 2 inches for DWL gives a D/L of 232. This is not a light boat. L/B is 2.53 indicating plenty of beam, as if your eye had not already told you that. Draft with the board down is 5 feet 7 inches and the board-up draft is 2 feet 4 inches. There are twin rudders.

The accommodation plan is pretty amazing considering it is a 29-foot boat. The expansive capital-U-shaped berth has replaced the dreaded V-berth. The bad news is that the U-double berth is an extension of the main cabin settee, so there is no privacy forward. The good news is that it will be very convenient to have breakfast in bed. There is a double quarterberth aft, but it’s pretty tight with just enough standing room to pull on your pants.

The galley is big for this size boat. I don’t like stoves up against a bulkhead so I would move that stove forward to line up with the forward counter then put counter aft of the stove. I like to be able to put pots either side of the stove. But there is quite a bit of counter space as drawn. There is a forward-facing nav station to starboard and a small but adequate head aft.

I was out racing last weekend and studying the square-topped mainsails in the fleet. The more I looked, the more the shape made sense and the pointy-headed triangular mains began to look silly. Square-topped mainsails mean you can’t have a standing backstay but with enough spreader sweep that’s not a problem. Spreader sweep angle on the Revolution looks to be 28 degrees. The SA/D of the Revolution is 23.37 and that’s plenty of power for some exciting sailing. 

One thing for sure  is that working on the foredeck will be easy. The headstay is about 20 inches aft of the stem so there is lots of room to work around it. On deck, a retractable sprit can be mounted for the asymmetrical chute. Interestingly, the cap shrouds go to chainplates on the rail. The lower diagonals go to chainplates inboard near the edge of the cabintrunk. This will make it easy to get past the shrouds when you go forward.

I would hope this look provides the owner with blistering speed and sumptuous comfort. 

LOA 22’8”; Beam 11’6”; Draft 3’7” (board up), 8’6” (board down); Displ. 8,818 lbs.; Ballast 2,425 lbs.; Sail area 743 sq. ft.; Auxiliary 18-hp diesel; Fuel 11 gal.; Water 66 gal. 

Sailaway price: $145,000

Afep Marine

Plateau Nautique

50 Rue Senac de Meilhan 

17000 La Rochelle, France

+33 (0) 54 644 81 51

www.afep-marine.com

Also in Perry on Design

• Full Circle 30
• Tanton No. 309
• Dragonfly 40
• Wallyrocket 51
• Clubswan 28

Also from Robert H. Perry

Secrets of the new Jérémie Beyou’s IMOCA Charal 2 With Scow Bow Unveiled

The 46-year-old French skipper Jéremie Beyou is certainly nowhere near finished with the IMOCA Class and nor with the Vendée Globe, and gets out of bed every morning driven by the goal of finally winning a race that has so far eluded him. In a few days, he will launch his new IMOCA, Charal 2 – this time from the board of Sam Manuard with its signature scow bow – and the goal for this boat is crystal clear, as Beyou told the Class when asked what it was that is driving him on.

“Getting back to the Vendée Globe and winning it,”  said the man who won justified acclaim for the way he stuck to his guns when finishing 13th last time out, having started as one of the favourites.  “That’s what’s driving me and I think I have the ability to do it and the team to do it and I really have a really strong motivation, so that’s it.”

But could this be his last new IMOCA?  “That’s the big question,”  replied the three-time Figaro winner and Volvo Ocean Race winner, laughing as he considered his response.  “I can tell you I have all the focus for next time; for 2028 I am not sure. I will tell you after the next one. But I am still really passionate about what I am doing and I have a real chance. So every day I wake up and I come to the shipyard or to the design office and I realise the opportunity I have, so you never want it to stop.”

This new IMOCA is fascinating because Beyou and his team have again built early in the cycle, but have stepped away from VPLP who they used for Charal 1 – the first of the 2020 generation of new foilers – and chosen Manuard instead. This was a decision partly based on an assessment of Manuard’s first IMOCA project, originally launched as L’Occitane En Provence (now Bureau Vallée), which impressed Beyou with its outright speed. But also on the readiness of Manuard to work with the Charal design team.

Beyou is quite open about the fact that the relationship between Guillaume Verdier and the design group at MerConcept, who are producing a new boat for Charlie Dalin, Beyou’s main rival at the top of the Class, was an example he wanted to follow.  “I think that is one of the big strengths of APIVIA and MerConcept,”  he said.

“They have everything inside the team. They work with Guillaume Verdier , but I think Guillaume leaves the team do a lot of it. He supplies the ideas and then the design team at MerConcept, make it happen. That’s the way we are trying to work with Sam. He has a lot of experience and is convinced by some design ideas but, at some stage, it’s the team inside Charal 2 that makes things happen, so that is why we changed.”

Beyou makes the point that design teams at the sharp end of the IMOCA world do not just do their work every four years and then melt into the background; they should ideally be a core part of a sailing team in order to drive the continuous evolution of a boat throughout its early racing life. In the last cycle, the revisions and improvements on Charal 1 were relentless, with modifications to almost every aspect of the boat – hull shape, rudders, keel, foils, ballast, deck fittings and sails.  “Evolution is a continuous and permanent process,”  he said.  “That is a central point of the mindset of our sponsor, Charal, in their work in the meat products industry and they wanted to do something similar with us, so that’s the way we work too.”

Jéremie Beyou has not lost the appetite for driving change on his new boat should it be required, but he is hoping they have got the hull shape more or less right.  “This time, with all the data we have and all the experience we have, I think we won’t have any more to do concerning the hull shape,”  he said.  “But we know that with ballast volume, bulb weight, sails and appendages and so on we will have changes to make.”

The new boat is based on extensive analysis of Charal 1 and L’Occitane en Provence with the goal of trying to produce a fast, stable and efficient hull shape that is manageable in strong conditions downwind, when the last generation of IMOCAs tended to crash into the waves and stall.  “For sure L’Occitane en Provence was much better for the Vendée Globe for going downwind in big seas,”  said Beyou.  “So yes, that was part of the design. We compared everything between the two boats…and Sam had the intelligence to say that while he was convinced of the type of hull we needed for the Vendée Globe, he was happy to consider a different hull shape too.

“So we studied both concepts,”  he continued,  “and at the end we knew that we needed something with a kind of scow bow, something with more righting moment than Charal 1, but we needed the whole package not to drag too much in the water. So the hull is not large – I think it is the least beamy IMOCA ever designed and the boat is quite like L’Occitane en Provence.”

The cockpit is based on the earlier Manuard IMOCA too, but has detailed changes to improve the life of a solo skipper.  “I had the opportunity to visit the boat of Armel Tripon (the former L’Occitane en Provence skipper),”  explained Beyou.  “The cockpit was really nice and you have great vision of everything happening on deck. The cockpit is generally the same, but we have new details on it too. We worked a lot on ways to be able to trim the sails more easily, so we have more winches on Charal 2 than Charal 1 and more hydraulics. And with the appendages, the idea was exactly the same as with the hull shape – to have a boat that goes straight and is stable – so we put every effort into that.”

The new boat will make its debut at the Défi Azimut-Lorient Agglomération in September and then take on its first big race at the Route du Rhum-Destination Guadeloupe in November. Among its rivals in that contest will be not just the old APIVIA, and Bureau Vallée in the hands of Louis Burton, but new boats like Kevin Escoffier’s PRB, Maxime Sorel’s V and B-Monbana-Mayenne, Boris Herrmann’s Malizia-Seaexplorer, Yannick Bestaven’s Maître CoQ, Sam Davies’s new sistership of L’Occitane en Provence, Initiatives-Coeur and Paul Meilhat’s Biotherm.

Beyou believes the next winner of the Vendée Globe in 2024-’25 will come from this latest generation of foilers, but he is not putting his house on it.  “I am certain but I was quite certain last time, so don’t put money on it please,”  he said.  “But that’s yacht racing and the weather is the deciding factor with everything, so it is difficult to say. We can see that older boats that are changing their foils are going really well, so it is more difficult to say. But I think the boat that will win it, and the skipper that will win it, will have done a big amount of work beforehand.”

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The scow bow phenomenon explained by “guru” Sam Manuard

• October 13, 2022
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Scow bows, that is, those with round front volumes, are the future and present of ocean openers, and perhaps not only of ocean openers, as they have completely revolutionized the performance of boats such as the Mini 650s, the Class 40s, and some of the Imoca 60s. There are in fact no longer any winning boats in Ocean races equipped with “classic” bows, a fact that enshrines a design evolution from which there is unlikely to be a return.

Can scows also have a future in the cruising world? Too early to tell, we talked about it with “guru” Sam Manuard , the French designer who designed Alberto Bona’s Class 40 IBSA and is regarded as one of the most successful designers in the Ocean at the moment. The full interview, with contributions from Italian designers Gianluca Guelfi and Oris D’Ubaldo, will be published in the November issue of the Giornale della Vela, print edition.

Prue Scow – Sam Manuard’s Word.

The concept behind making scows is to avoid sinking the bow underwater. In the scows the bow instead of cutting through the water will stay high on it. The shape is so wide and flat that it creates hydrodynamic lift, which also helps the boat get some lift to break away from the waves. These types of bows have been shown to be much more efficient in wave-carrying swells than standard bows, and in general they are very efficient in any swell that has waves from 60° angle onward.”

Scow Bows – A future in cruising?

“Each type of design has some pros and some cons. The main drawback of the bow scow is the violent upwind slamming in formed seas because of the shape and amount of the boat’s forward volumes. Would you really like to bang like that on a cruise with friends and family? I don’t think so. However, we could take this concept, the scow, and smooth it out a bit so as to get some of the advantages without penalizing too much of the going with opposite wave and then propose it, with different characteristics, for non-racing boats as well.”

Scow Bows – The design of the Class 40 IBSA by Alberto Bona

“Alberto’s boat is what we might call an allround hull, but one that will show its maximum performance in strong sternwind conditions. To achieve this, that is, control and performance in the stern in strong winds and good average performance in all other conditions, we have increased the overhangs of the bow, which is high on the water, and as a result we have reduced the length of the waterline overall.”

Mauro Giuffrè

THE FULL STORY IN THE NOVEMBER ISSUE OF THE SAILING NEWSPAPER PRINT EDITION

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5 new sailing scows aimed at the cruising market

There has been a raft of new sailing scows announced this year, with the cruising market following the racing world in design philosophy

Those who followed the early stages of this year’s Rolex Fastnet Race will surely have been intrigued by how well the front runners in the Class 40 fleet appeared to handle the brutal wind against tide conditions that caused problems for a lot of other boats. Conventional wisdom has it that a slim, narrow hull is ideal for sailing upwind in a blow. Yet the recent Class 40s carry their immense beam well forward of the mast, with a bow that’s closer to a square shape than a conventional point.

However, when heeled these boats present a relatively narrow immersed section that doesn’t slam into a head sea with the intensity that the flat saucer-like hull might suggest. At the same time they have enormous righting moment, which gives power to punch over big waves and reduces the total time spent sailing to windward. This stability is also an important factor in the boats’ behaviour in strong gusts: an increase of wind that would have many of the rest of us scrabbling for another reef is often handled simply by depowering the top of the mainsail with a bit more twist.

Although this hull form has only been in existence for little more than a decade, since David Raison won the 2011 Mini Transat in a boat of his own design, it has quickly gained traction across the Mini 6.50, Class 40 and IMOCA 60 fleets. It’s now increasingly appearing in designs for cruising yachts, which also have potential to offer considerably more internal volume than other vessels of a similar length.

The Skaw Paradise is a very beamy 11.3m foiling scow bow cruiser with its roots firmly in the racing scene, but with the concepts reworked to produce an ultimate cruiser. Skaw CEO and founder Benoit Marie is also technical director, coach and co-skipper (when racing double-handed) for Caroline Boule, who’s notched up a string of impressive results in the Mini 6.50 class this season in her full flying Sam Manuard-designed Nicomatic.

Marie co-designed the Skaw Paradise with naval architect Clément Bercault of Berco Design. “We could not find any boat on the market suiting our needs, so we started designing our own perfect boat,” he says.

“It’s one to take our friends and family around the world to unseen places, in the safest, easiest and fastest manner.”

The Skaw Paradise differs to Nicomatic in that it has fully retractable C-foils that are intended to act like motion dampeners, giving a smoother ride, while also increasing both stability and speed. While much is borrowed from the racing world, this boat has been simplified as much as possible, so it’s not complicated to sail.

Much of the drive towards scow bow cruising yachts is driven by top level racing sailors. Armel Tripon, who raced the then radical Sam Manuard-designed IMOCA 60 L’Occitane de Provence in the 2020 Vendée Globe, has lent his name to the SailScow brand that’s working on a range of four designs from 28-42ft.

“The hull I was able to test racing around the globe delighted me,” says Tripon. “I can easily imagine myself cruising on a scow to take full advantage of the sailing performance, the ease of passage through the sea and the incredible comfort at anchor – I can’t wait to try it out.”

The first SailScow model is a 37ft cruiser designed by Gildas Plessis, a strong advocate of this hull shape. It’s primarily of marine ply and epoxy and offers a step change in internal space compared to other yachts of this length. Options include a four cabin layout, with two doubles forward, both with rectangular beds, while aft there’s a further double, plus a twin cabin with bunk beds. Alternatively there’s space for a giant owner’s cabin forward, plus one aft double port and a generous technical and stowage area to starboard.

VPLP Fast Cruising Scow

PLP’s carbon Fast Cruising Scow is a 40ft concept that aims to maximise both performance and comfort. It has a covered and glazed saloon/cockpit area like those found on cruising catamarans. On the same level as the working areas of the cockpit, it provides shelter from sun and water both when used as a dining area and as a watch keeping zone on passage.

Air draught a fraction over 20m (67ft) helps provide a big rig that will produce plenty of power, while retractable foils will reduce heel angles thanks to the righting moment they generate, at the same time as cushioning the passage of the boat through waves.

Breton yard IDB Marine was one of the forerunners in producing a cruising boat based on a scow bow design. The Mojito 650 uses the same extreme scow bow hull as the phenomenally successful David Raison-designed Maxi 650 that won the series division of the last Mini Transat race, taking five of the top nine places.

The Mojito 650 is a detuned boat with a new coachroof that gives a panoramic view, plus a six-berth interior with a full-size rectangular double bed forward. There’s also plenty of stowage and all that’s lacking compared to many significantly larger craft is standing headroom and a separate heads compartment. A smaller and simplified rig compared to that of the Maxi 650 makes this an easy boat to sail and a lot less tweaky than the original, yet it’s still one that will happily plane at speeds well into double digits and hold its own upwind against boats 10ft longer.

La Rochelle-based RM Yachts has been forging a different path to mainstream yards for more than 30 years with its range of distinctive fast plywood/epoxy performance cruisers. The latest model – a sixth generation RM designed by Marc Lombard, is directly influenced by today’s raceboats, with the aim of producing a spacious, fast and dry 36-footer that can cover long distances at fast average speeds.

“It offers greater safety, more interior and exterior space and greater ease of movement,” says lead designer Eric Levet. “The hull is powerful and voluminous but not excessively so at the bow, for a good passage through the waves.”

The first example is scheduled to start construction in January next year and is expected to be afloat in July 2024.

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Published on October 11th, 2022 | by Editor

Scow bows rule the seas

Published on October 11th, 2022 by Editor -->

Class organizations such as the Mini 6.50, Class40, and IMOCA support offshore competition, and when courses are long enough, routing seeks out the benefits of offwind angles. Over time, designing to these class rules have developed hulls that may not go upwind too well but more than make up for it as the wind angles comes back.

Such as the scow bow.

Sam Manuard is a renowned architect in the scow world, and what began as a radical concept with the Mini Class, has seen its success trickle up to the Class40 and IMOCA which will be on full display in the 2022 Route du Rhum when it starts November 6.

These big bowed boats will be spanning the transatlantic from France to Guadeloupe, with the 3543nm course providing the latest test. Here are some comments from Manuard in boatsnews.com :

Regarding the state of design: Nowadays, everyone makes scows. There is no more debate on the subject. There are always nuances on the scow theme. Lombard with the Lift has made a very powerful boat, VPLP with the Clak40 which looks more versatile. It’s progressing well and the different designs are pretty close in performance. Everyone has raised their game.

Versatility versus all-around performance: We are interested in the statistical distribution of wind and speed for this type of race. We also look at races like the Fastnet, the Normandy Channel Race to have a boat that is efficient in light airs, that goes upwind well. Having a flat spectrum is quite interesting. In the design loop, the Mach5 (his latest design) has the Route du Rhum as its primary objective. But also the other races, not necessarily with the same level of priority. In any case, the choices made should be effective on all types of races.

But for an offwind race like the Route du Rhum… With an increasing number of scows, the classic (non-scow) boats no longer have a chance of winning.

Tags: boatsnews.com , Class40 , Route du Rhum , Sam Manuard

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How to make a better yacht bow

When asked most seafarers say that a bow’s job is to enable a vessel to pierce through waves, slides over waves, keep water off the foredeck, or even that it’s just a place to put the anchor and chain. But few realise that the bow shapes the waves that flow alongside the vessel. A badly designed bow will create unnecessary drag; while a good one will cut resistance and increase comfort.

Half-angle of entry

In most cases, the criteria for the design of the bow begins with the half-angle of entry. This is the naval architect’s term for the more commonly known ‘horizontal bow angle at the waterline’.

A yacht with a large half-angle of entry will slam into, or at least fight, waves often throwing a lot of spray and green water ahead of it. A vessel with a fine entry and narrow half-angle will slide right through a wave with little resistance.

As a yacht’s half-angle of entry increases, the bow becomes more prone to slamming into waves, which in turn, requires more power to keep the yacht moving steadily into the sea and tends to increase pitching.

The angle of entry at the bow is defined by the yacht’s speed and function. In a sailing yacht, the half-angle might be between 10 and 20 degrees, with 10 degrees being a fine entry and 20 degrees being more suited for a slower displacement yacht.

On a motor yacht a fine angle of entry, say 12 degrees, is suited to high-speed semi-displacement style yachts, whereas a normal half-angle is between 18 to 24 degrees.

A very fine half-angle – less than 10 degrees – is to be avoided. It makes the bow narrow and reduces the forward volume of the hull forcing lockers, gear and equipment aft. That said, a long, narrow vessel will have a finer angle of entry than a short, wide vessel, so a specific half-angle of entry should only be used as a comparison factor on vessels of similar length and beam.

The widest half-angles of entry – from 30 degrees to more than 40 degrees – are rarely found on yachts, but can be seen on scow-type barges that move at very slow speeds and throw a lot of water ahead of the bow. These cargo carrying vessels don’t have passengers and move slowly, so wave impacts and slamming can be accepted.

However, if the wave is very large and the yacht has a narrow half-angle, the wave might simply rise up and wash across the deck. To eliminate this designers often flare the upper bow so the rising wave crest is turned back into the ocean.

The most extreme example is what has become known as the ‘Carolina flare’ on convertible sportfishermen built on the Outer Banks

Types of bows

Designed originally to combat the waves off the Carolina inlets, the so-called Carolina flared bow is often attributed to sportfishing boats built by Buddy Davis and the others of The Outer Banks. The idea is that a fine angle of entry drives into the waves, but as wave size increases the flare rises up over them, throwing the water back into the ocean without getting the deck wet.

Typically, a flared bow will often have a chine or two low on the profile to 'break' the flow of water up the sides of the flare and help direct water away from the bow. In terms of propulsion, the gradual increase in buoyancy from a flared bow ensures that a wave does not impact the bow with a hard crash, but is gently turned aside while the bow lifts to the wave.

This type of bow usually has a chine or lifting strakes carried well forward which also helps throw water to one side and provides additional buoyancy as the bow dives into a wave. The force of the bounce increases with depth and flare angle.

The biggest drawback of this type of the Carolina Flared bow is that, as the yacht slams into a wave, the gradual immersion of the flare causes the bow to pitch upward (vertical acceleration), making the entire yacht pitch, plus the vessel slows down as it pitches requiring more power (read higher fuel consumption) as it drives ahead.

Another drawback is that should the bow submerge, it acts like a giant scoop to dig into the water and throw it across the deck. For this reason, some builders incorporate considerable camber to the foredeck.

When designing such a bow, the designer needs to have a pretty good idea of the height of the waves the vessel is likely to encounter.

Bulbous bows

Bulbous bows are generally only found on displacement hulled yachts – that is, yachts that will not exceed about 1.5 x √LWL, or the Froude number for that hull. Marlow yachts, which are semi-displacement, have an option for a small, delta-shaped bulb that is flat on top and V-shaped below to both break the water and offer some resistance to pitching when performing above displacement speeds. (Bulbous bows work best when the yacht is moving at .9 to 1.2 x √LWL.)

The idea of the bulbous bow is that the wave generated by the bulb reduces the size of the bow wave and hence lowers the resistance of the entire hull. The size of the bulb is most often determined by tank testing when the shape of the bow wave and the bulb’s cancelling effect can be clearly demonstrated, but in general terms, the larger the bulb is, the greater the reduction in resistance as long as the yacht is moving in a relatively flat sea. When the vessel is pitching, the bulb can actually increase hull resistance.

However, a designer needs to be aware of the interplay between the size of the bulb and the anchor handling gear. It would not do to bounce the anchor off the bulb every time the yacht is anchored.

Japanese researchers have found that a bulbous bow along with a slight reduction in the hull waterline beam just aft of the bow, will reduce hull resistance even farther, but at the cost of a reduction in cargo carrying ability and more complexity in the vessel’s construction.

Types of bows (continued)

The opposite of the flared bow is the Axe bow, such as the scimitar bow on the Amel 199. Here where instead of increasing the flare above the water, a very narrow half-angle of entry is maintained from hull bottom to the deck, but extra buoyancy is built in below the waterline with a deeper forefoot, and the sheerline forward is raised against green water on deck.

This type of hull has with lower resistance and creates less pitching in a seaway than a flared bow. Although this shape of bow cleaves waves, it is wet in a seaway.

Experiments in The Netherlands have shown that instead of increasing buoyancy by flaring the bow above the water surface, axe bows increases buoyancy by bringing the underwater bow profile downwards and raising the sheer at the bow.

Not only do these features lengthen the vessel considerably, but they also make it easier to drive into head seas, requiring less power. In addition, it has been suggested that up to 20 per cent lower fuel consumption in head seas can be achieved because the bow does not have the vertical accelerations of a flared bow.

A relatively new trend for larger craft is the scow bow. It has been a fixture on Great Lakes A and C class sailing scows for many years, but its potential was suddenly realised when a Mini-Transat boat with a scow bow handily won the race. Now, designers Reichel-Pugh have designed a 27.4m sailing yacht with a scow bow.

This type of bow carries beam well forward with the intent that the waterline length is increased as the boat heels. The major drawback of scow bows is they slam when upright and on a large yacht, that might be more than the owner is willing to accept.

Wave piercers

The totally opposite look to the Apple Cheek bow is the Wave Piercing bow as used by Craig Loomes Design of New Zealand and others on several superyacht and fast ferry designs.

The idea behind this bow is that the extended sponsons on each side of the catamaran or trimaran hull pierce the waves to reduce pitching in heavy seas. In this style of yacht, the main hulls have less buoyancy forward to allow it to slide through the wave rather than slam into it. By sliding through the waves, less engine power is required and the pitching of the yacht is lower.

The bow is an essential feature of any modern yacht. Elongated bows such as the wave-piercing bow, reverse or axe bow lengthen the waterline and make the angle of entry finer, decreasing the hull resistance of faster vessels and reducing pitching in a seaway. However, the longer waterline can make it harder for the vessel to turn. Meanwhile, bulbous bows decrease the size of the bow wave and consequently reduce hull resistance for vessels that operate at a set displacement speed and load.

A designer should pick the bow shape that is best suited for the desired speed, shape and pitching characteristics in a seaway.

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(Scow bow) - vs - (Wave piercing bow)

Discussion in ' Boat Design ' started by Gunnar Sommerlund , Jul 10, 2017 .

Gunnar Sommerlund Marine Engineer

Hello, this is my first time on this forum "i have been lurking around". <- (Bear with me) I haven't been able to find information regarding " differences " between scow and piercing bow types. I know that a sharp bow has a minimal wet surface, while scow i focused more about planning capabilities and is popular in lake sailing (in America). The reason i,m asking is because i have decided to spend next couple of years designing a sailboat in range of 25' to 30' foot. for sailing inshore waters of Denmark, and participating in local races now and then. The Scow seems to be gaining popularity (in mini transat) and i cant stop wondering why there arent more of them around. I have uploaded an example of arkemas mini transat and figaro 3 . I Absolutely love their designs. They are both made for open ocean right?  

Doug Lord Flight Ready

The scow shape for Mini's began with David Raisons boat a few years ago and has proven to be very fast. The newest versions like Arkema and SeAir have taken another major leap in technology utilizing lifting foils to completely fly the boat. And two years ago Hugh Welbourn and Quant boats introduced the worlds first foiling keelboat scow the Quant 23.Very exciting times! The Quant 23 takes off in a 5 knot breeze and foils upwind in 7-8knots of wind. It uses a unique foil system that doesn't require constant adjustment and that drastically increases the righting moment of the boat. According to those that have sailed it ,it is very easy to learn to fly: SeAir Mini with Welbourn foil system:  

Doug Lord said: ↑ The scow shape for Mini's began with David Raisons boat a few years ago and has proven to be very fast. The newest versions like Arkema and SeAir have taken another major leap in technology utilizing lifting foils to completely fly the boat. And two years ago Hugh Welbourn and Quant boats introduced the worlds first foiling keelboat scow the Quant 23.Very exciting times! The Quant 23 takes off in a 5 knot breeze and foils upwind in 7-8knots of wind. It uses a unique foil system that doesn't require constant adjustment and that drastically increases the righting moment of the boat. According to those that have sailed it ,it is very easy to learn to fly: View attachment 134445 SeAir Mini with Welbourn foil system: View attachment 134446 Click to expand...

Gunnar, I haven't sailed a Mini but while I think the new scows are amazing I think they are not pretty in the traditional sense. I guess it depends on what you want to do. I would consider using foil assist if not full flying. Good Luck!  

gonzo Senior Member

The Mini Transat has developed boats specialized in downwind sailing. If that is what you are considering, the blunt bow and shape conducive to surfing is great. For an all around boat, it is not the best.  

SamSam Senior Member

Here's an article in a "Yazi" magazine about bow types. On page 3 they discuss (a little bit) about the 2 types you're interested in. How to make a better yacht bow http://www.boatinternational.com/yachts/yacht-design/how-to-make-a-better-yacht-bow--799 You might try 'searching' in the various forums here. Also, usually at the bottom of the page of whatever you are looking at is a list of 'similar threads' which is an automatic search feature. Welcome.  

gonzo said: ↑ The Mini Transat has developed boats specialized in downwind sailing. If that is what you are considering, the blunt bow and shape conducive to surfing is great. For an all around boat, it is not the best. Click to expand...

Search Results for Query: piercing bows | Boat Design Net https://www.boatdesign.net/content-search/92268/?q=piercing+bows&t=post&o=date Search Results for Query: scow bows | Boat Design Net https://www.boatdesign.net/content-search/92270/?q=scow+bows&t=post&o=date  

Gunnar Sommerlund said: ↑ That is good to know. Becouse i,m looking for a design that preforms well inshore. Coastal cruising no more then 20 miles from shore. Click to expand...

Thank you guys for the links. I will lurk arround and post what crazy ideas i come up with =)  

CT249 Senior Member

One issue is that one of the big benefits of the scow is that they increase righting moment, but often at the expense of extra wetted surface and wave drag as I understand it. The extra righting moment is more of a plus if you have a big rig, and the extra drag is less of a problem if you have a big rig and a significant problem if you have a small one. So you tend to see scow bows on boats with big rigs. In some ways, something like a 25 foot scow is often simply a 28 foot boat with the bow chopped off; in fact in some small boat classes where there was a length restriction and big rigs, designers just used to design a longer boat and then effectively chop the bow off at the desired length. So you had 14 foot "snub bow" boats that were effectively 16 footers with the front cut off. It may just underline how designing a boat to a set overall length is actually quite artificial in some ways. A 22' scow would often become a better boat for minimal extra cost if you added with 3' of pointy nose onto it. Which leaves one to wonder where the advantage is, if one is not limited by LOA.  

Scows, like the inland lake scows in the US and even the Mini scows are designed to sail at an angle of heel that reduces wetted surface and changes how the bow interacts with waves. You can see how much the wetted surface is reduced with the right angle of heel in the pictures below:  

PAR Yacht Designer/Builder

The advantage of a scow hull form is the heeled waterline symmetricity, compaired to a more conventional canoe body. A a scow heels and as Doug points out, the typical canoe body's WL's tend to become very asymmetric with a strong rounding moment, yet the scow's WL's are less so and move dramatically to leeward, increasing the couple, but also decreasing resistance. Comparing a fine bow canoe body, particularly if fat butted for downwind efforts, to a scow just isn't a fair comparison. They're using different principles and hydrodynamic tricks to get their performance envelop. For inshore cruising and occasional racing, the more common triangular canoe body would be the reasonable choice. The scow is a fairly specialized hull form and you'll get dinged pretty hard, if you show up at the local 'round the buoys event, with a scow against a bunch of canoe sloops. Lastly, the scow hull form isn't the best choice for a cruiser, IMO, just no internal volume, which is high on the priority list in a cruiser.  

Paul, when you compare a "Mini" scow hull with another 21-22 footer the Mini has a ton of internal volume but the 28' E scow sure doesn't-like you said.  

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PAR said: ↑ The advantage of a scow hull form is the heeled waterline symmetricity, compaired to a more conventional canoe body. A a scow heels and as Dog points out, the typical canoe body's WL's tend to become very asymmetric with a strong rounding moment, yet the scow's WL's are less so and move dramatically to leeward, increasing the couple, but also decreasing resistance. Comparing a fine bow canoe body, particularly if fat butted for downwind efforts, to a scow just isn't a fair comparison. They're using different principles and hydrodynamic tricks to get their performance envelop. For inshore cruising and occasional racing the more common triangular canoe body would be the reasonable choice. The scow is a fairly specialized hull form and you'll get dinged pretty hard, if you show up at the local 'round the buoys event, with a scow against a bunch of canoe sloops. Lastly, the scow hull form isn't the best choice for a cruise, IMO, just no internal volume, which is high on the priority list in a cruiser. Click to expand...

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Yachting World

• Digital Edition

Ugly – but fast?

• Elaine Bunting
• April 16, 2012

The latest hot trend in ocean racing design is the scow bow. But it's ugly and it looks as if it'd be brutal upwind

I’m torn when I think about the latest trend for ocean racing, the scow bow. On the one hand, it’s a fascinating development. On the other…cripes, these new designs are ugly.

Round bowed scows have been well proven; the skimming dish designs have long been popular in the US, though less so in Europe. Yet the design principle made no major inroads into offshore design until last year, when French engineer and solo sailor David Raison won the Mini Transat in his self-designed mini 6.5m Mini Magnum/Teamwork Evolution.

This round bowed, push-me-pull-you 21-footer beat the 2nd placed prototype Mini to the finish in Brazil by 130 miles – a huge margin in such an evenly matched fleet – and recorded an average across the entire Atlantic of 6.8 knots.

He nicknamed his wide-bodied design ‘le gros porteur’, the jumbo jet, in reference to its max beam, carried as far forward as possible.

Now there is a proposal from design group Reichel/Pugh for a 90ft scow (pictured above) designed to attempt to beat the Transpac record. We’ve got a full report on this intriguing design in our May issue.

The basic principle of the scow design is to maximise hull righting moment. The beam is carried well forward which means that, when heeled, the hull lines are further outboard than with a conventional bow. This makes the scow design very powerful when reaching, obviously important on races such as the Mini Transat or the Transpac, which have a predominance of reaching conditions.

It has the added advanced advantage of large reserve buoyancy in the bow to prevent the bow from burying or nosediving when driven hard off the wind.

Put that together with a canting keel, as is the case on David Raison’s boat, and you have a potentially very powerful yacht indeed.

However there are two snags with this design.

The first is that, upwind, the rounded bow slams, even when well heeled. This means it may not be that versatile a design or particularly comfortable in all-round conditions.

And in view of what are seeing in the Volvo Ocean race, which has suffered multiple structural problems in the harsh seas of the Southern Ocean, it would be a very brave designer (and sponsor) indeed that plumped for a scow design round the world or more general racing conditions.

Secondly, let’s face it: these two new extreme scow designs are not pretty. Would you want a yacht that looked like this? I wouldn’t. If your boat was jarring as this, you’d have to win.

But since Raison’s dramatic victory, I suspect designers everywhere have been playing around with the scow idea. In classes whose rules don’t place a restriction on maximum righting moment, it’s an obvious idea to explore. If it takes off, clever minds may even find some creative ways of softening the brutal front end.

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