Scow with a hint of bow?

[gonzo]

Assuming the speed is equal, but they are uncomfortable, makes for a production boat that is hard to sell. This thread is focused on a boat for the general public, so comfort is high on the requirements. Also, Class 40 boats have really deep keels which makes them unsuitable to many marinas and anchorages; the mainstay of cruising.

 

[DVV]

Assuming the speed is equal, but they are uncomfortable, makes for a production boat that is hard to sell. This thread is focused on a boat for the general public, so comfort is high on the requirements. Also, Class 40 boats have really deep keels which makes them unsuitable to many marinas and anchorages; the mainstay of cruising.

I agree with you on this, it would be a minus on the cruising vessel. I was going a bit off topic

 

[gonzo]

Not completely off topic. People buy Ferraris to go shopping, but they would be terrible as a camper.

 

[CT249]

I dont think the wave piercing bow is a good comparison.
Scows are nothing new, they have been developed many times: garveys, ausrialian scows, even the first moth were square bowed.
The fact that for a limited length the scow shape is faster is not new. These types of vessel have been banned from competition in the past due to their superior speed.
They are still banned in Class 40 and in IMOCA, but they are not banned in Mini class, and they win.

Yep, completely agree that scows aren't new; my own first boat was a scow Moth. Yes, arguably scows are normally better only when length is limited. I'd add that on most waters, they also only really work well when the rig is big. Boats with rigs of small to average size rigs (NS14s, MG14s, National 12s, Merlin Rockets, Renjolle, Rs, most long windsurfers, 5.5s, Micros, etc etc etc) tend to have fine bows.

The comparison with the wave piercing bow is that arguably, some people have become excited about both wave piercers and scows (which are at the opposite end of physical shapes) because they think they are cool, rather than because they work better in all boats.

 

[DVV]

Not completely off topic. People buy Ferraris to go shopping, but they would be terrible as a camper.

Thinking about cruising, I think a V bottomed scow (like they use to do in garveys) could be an interesting vessel, it should pound less in a chop.
What do you think?

 

[DVV]

Thinking about cruising, I think a V bottomed scow (like they use to do in garveys) could be an interesting vessel, it should pound less in a chop.
What do you think?

The last Class40 built, which made second in the last Route du Rhum, has a slight v in the bow

 

[wet feet]

By comparison, the winner of the category has a cabin that looks more streamlined than the hull.The thing about all categories of racing artefacts is that if they perform,they are considered beautiful.It's just as well the boat does achieve results because it would otherwise be fairly ugly.I can see some benefit in having such a large reserve of buoyancy forward of the mast as well as having more internal space to spread out in.I don't believe it is the answer for all locations and all uses.

 

[CT249]

Thinking about cruising, I think a V bottomed scow (like they use to do in garveys) could be an interesting vessel, it should pound less in a chop.
What do you think?

The issue is that a low deadrise Vee hull heeled at a normal angle can present a dead flat surface to the waves.

It's the opposite of some IOR boats, which pounded hard enough to break frames when motoring because of the flat bottomed bow sections, but were more seakindly under sail because the flat section then became inclined to the waves.

Like the Minis, the Class 40s are largely unknown out of one corner of the world. In a way it's strange that their design excites so much interest. I do wonder whether they mainly excite the interest of people who didn't grow up in dinghies, because to people who grew up in classes like Optis, Sabots, Toppers, and Mirrors there's nothing so unusual about a scow.

 

[gonzo]

Thinking about cruising, I think a V bottomed scow (like they use to do in garveys) could be an interesting vessel, it should pound less in a chop.
What do you think?

I think that scows have a large volume for their length compared to more conventional shapes. That is attractive to people that sail occasionally and mainly spend time at the dock or live aboard. If you look at racing scows, they sail upwind fairly heeled to present a narrower waterline and finer lines forward. Garveys pound less when motoring but would have a flat horizontal surface when sailing upwind. In my opinion, all extreme racing designs are not the best for cruising.

 

[CT249]

The thing about all categories of racing artefacts is that if they perform,they are considered beautiful.

Racing success can definitely change the general opinion about a shape's aesthetics (the classic Metre Boat/Dragon bow was once considered hideous) but some successful shapes are always considered ugly. I can't recall anyone praising the looks of a typical lumpy Stephen Jones IOR boat despite the fact that they were very successful in the UK, nor did anyone claim some of the strange IMS shapes were pretty. Myth of Malham and her successors got a lot of criticism for their aesthetics, and that criticism hung around until the reverse sheer/short end look died away. I can find no positive comment about the aesthetics of the old snub-bow classic Australian "skiff" types, despite their enormous success. Formula Windsurfing boards went really fast, as do the current windfoiling boards, but I've never heard anyone call them attractive whereas any old curvy and skinny pintail "gun" surfboard or sailboard or wooden Malibu surfboard, no matter how badly it went, is likely to end up on display in a cafe or house.

There's also lots of racing boats that were not particularly successful that are renowned for their beauty; a quick google for the most beautiful classic yachts brought up boats like Moonbeam and Black Swan, which weren't particularly successful in their early days. We may also just get an misleading belief of which racing artefacts are the best performers because we tend to mainly see references to those that had some aesthetic values. There would almost certainly be more pictures around of the pretty Dorade than the ugly Myth of Malham, although both were very influential and Myth may actually have been more influential than Dorade.

Perhaps what normally happens is that people largely ignore ugly winners; that rules are changed to give prettier boats an equal chance; or that designers learn to incorporate the good points of the ugly boat into a more attractive shape?

It's interesting to look at the prints and images chosen by non-sailors. They tend to go for classically beautiful shapes, which makes me wonder why we ignore aesthetics in the desperate desire to get publicity for sailing. To non-sailors an Open 40 scow probably looks silly, not exciting.

 

[DVV]

The issue is that a low deadrise Vee hull heeled at a normal angle can present a dead flat surface to the waves.

It's the opposite of some IOR boats, which pounded hard enough to break frames when motoring because of the flat bottomed bow sections, but were more seakindly under sail because the flat section then became inclined to the waves.

Like the Minis, the Class 40s are largely unknown out of one corner of the world. In a way it's strange that their design excites so much interest. I do wonder whether they mainly excite the interest of people who didn't grow up in dinghies, because to people who grew up in classes like Optis, Sabots, Toppers, and Mirrors there's nothing so unusual about a scow.

I am interested on scow

The issue is that a low deadrise Vee hull heeled at a normal angle can present a dead flat surface to the waves.

It's the opposite of some IOR boats, which pounded hard enough to break frames when motoring because of the flat bottomed bow sections, but were more seakindly under sail because the flat section then became inclined to the waves.

Like the Minis, the Class 40s are largely unknown out of one corner of the world. In a way it's strange that their design excites so much interest. I do wonder whether they mainly excite the interest of people who didn't grow up in dinghies, because to people who grew up in classes like Optis, Sabots, Toppers, and Mirrors there's nothing so unusual about a scow.

I would not put it like that. What you say is what pushes me: the two most sold sailing dinghies are Mirror end Optimist, both scow bowed (or pram bowed if you prefer).
The S.C.A.M.P. is scow bowed too. The OZ goose, the Brick. There are many scows that proved to be effective.
I wander if and how this shape could be used also in bigger vessels. Is it just a problem of look or what?

 

[wet feet]

I would add the Topper to that list: Topper (dinghy) - Wikipedia https://en.wikipedia.org/wiki/Topper_(dinghy) .Around a quarter of a million of them exist.The Wiki entry is slightly off the mark as the boat existed prior to 1977 and was not a roaring sales success.It was then re-designed for production using industrial plastic moulding technology and the huge investment in metal moulds soon paid off with massive sales.I remember reading an interview with Ian Proctor in which he said that the process required two machines,which were each used for dustbin production,to be connected to the huge mould and every few minutes a new component would pop out.

As for why the hull type seems to be increasingly popular for some forms of racing,I remember reading Weston Farmer's book a long while ago and in one section he was describing the effect of waterplane loading on boat behaviour.I have to believe that for a boat of any size there is a good deal more waterplane with a scow type hull and consequently a given displacement can be carried without the same draft that a more conventional hull would require.I suspect that there are benefits from the Coanda effect being less strong and the "wing loading" a lot lower.The obvious penalties are more material required to skin the boat and increased wetted surface in light winds.It can't be the answer in all situations but there are surely some where it works very well.

 

[gonzo]

I wander if and how this shape could be used also in bigger vessels. Is it just a problem of look or what?

Barges are usually scow shaped, and I would consider them big vessels.

 

[CT249]

I am interested on scow


I would not put it like that. What you say is what pushes me: the two most sold sailing dinghies are Mirror end Optimist, both scow bowed (or pram bowed if you prefer).
The S.C.A.M.P. is scow bowed too. The OZ goose, the Brick. There are many scows that proved to be effective.
I wander if and how this shape could be used also in bigger vessels. Is it just a problem of look or what?

As I understand it, the Mirror was designed with a pram bow because it's easier to build in ply than a stem. The pram/scow also gives more stability than a normal bow for the length, but I think most of those boats were built to a design dictated by length, such as being able to be built with one sheet of ply. I started sailing on an 8'6" pram, the Manly Junior, which was a snub bow so that it could be stored on-end inside a clubhouse about 8'8" high.

I've just been trying to get Optis going in my club, which is another indication that I'm not against prams or scows as such. The kids don't like them, sadly, because of their bow so we may have to go to O'pens instead, which aren't my idea of a good hull shape.

While Optis, Mirrors etc are great boats, whether they show that a scow cruiser is an optimal design is an open question. The pram bows hit waves but because of their small size and low speed it's not like a big boat hitting waves. The prams also don't normally sail heeled like a Mini scow does.

I admit I don't like the looks of the Mini and Open 40 scows at all, despite the fact that I grew up on a pram/scow and my own first boat was a scow Moth. But the main thing is that most of the reasons given for the modern scow designs seem to be related to creating a faster boat within specific class restrictions and that may not mean a better boat per se.

I'm also interested in the way the design spiral works, and the way we define and measure boat sizes, and both those issues are related to the issue of scow v "normal" boat.

 

[Dolfiman]

I'm also interested in the way the design spiral works, and the way we define and measure boat sizes, and both those issues are related to the issue of scow v "normal" boat.

I did the optimisation exercise for a day-boat type ULDB, but the optimisation mostly stays within the frame of the displacement mode (Froude < 0,45), and in short, all other things equal, the lengthy boat, the better performance :
Revisiting the ULDB option ..., for a day-boat project. https://www.boatdesign.net/threads/revisiting-the-uldb-option-for-a-day-boat-project.65582/#post-911483
Here our discussion with scow bow is actually about the aimed proportion of planing mode, which can break the length logic, changed for the sail carrying power.