How does a chine work?

[El Pinguino]

I have sailed on a number of big ships that had a flat run aft and a hard chine down there . Evil things in a following sea. Sea would come up under the quarter and suddenly all that buoyancy would come into play and she would be thrown over onto her ear... serious heavy rolling.
Flat runs work on planing hulls... not worth a POPS in hulls that just poke along

[Rustic Charm]

Originally Posted by Suijin

Dear lord, look at that beam. That makes it the smallest 38' boat I've ever seen and it looks really uncomfortable. The cockpit is minuscule! I understand the concept of making it fit in a container, but I can't for the life of me see why, in a boat that you're going to own, you'd be willing to make all those sacrifices for the sake of transit costs. Just pay to have someone deliver it, or put it on a boat, or just charter.

That's just wrong!

[clockwork orange]

Originally Posted by Suijin

Dear lord, look at that beam. That makes it the smallest 38' boat I've ever seen and it looks really uncomfortable. The cockpit is minuscule! I understand the concept of making it fit in a container, but I can't for the life of me see why, in a boat that you're going to own, you'd be willing to make all those sacrifices for the sake of transit costs. Just pay to have someone deliver it, or put it on a boat, or just charter.

I wonder if they sold any.

[Jim Cate]

Originally Posted by clockwork orange

I wonder if they sold any.

Of course not... this was a custom, one-off design that met the requirements of the fellow who paid Perry to do the design. He didn't give a rat's ass about whether anyone else liked it. This is why you pay a NA to draw these things... there are no production boats that meet the design criteria.

Actually, I vaguely remember that there were two built in the end, but I'm not sure!

Jim

[Polux]

Originally Posted by clockwork orange

I wonder if they sold any.

It was already posted : 2 But you cab still buy one, at least they still have the internet page.

It is an expensive boat with very small interior space but the interior looks better than on that plan. The most scary part for me is the need to go to the mast for reefing. That in a boat with so little initial stability is plain scary for me. I don't understand why they did not mount a reefing system from the cockpit.

[Delancey]

Ran across this interesting looking Class 40 inspired cruiser by Owen Clarke, who comments about the boat which features a lifting keel-

"The client had some very specific requirements and specifications for the vessel, not least the requirement for shallow draft. The first part of the design phase was to analyse the existing Class 40 hull for its suitability and to calculate the mass of the additional cruising fit-out and cruising payload. Fortunately the characteristics of an open type hull very much suit a cruising design in two significant ways: a) the hull is naturally high volume, excellent in terms of space for cruising, b) the large waterplane means that the yacht has far less sinkage (the depth the hull sinks when cruising payload is added) than a conventional hull form. For this client the ability to sail quickly from one cruising ground to another was also of high consideration due to the length of the Chilean coast, distances between harbours and unpredictability of the weather."

40' Blue water lifting keel cruising yacht : Owen Clarke Design - Yacht Design and Naval Architects

[clockwork orange]

Originally Posted by Jim Cate

Of course not... this was a custom, one-off design that met the requirements of the fellow who paid Perry to do the design. He didn't give a rat's ass about whether anyone else liked it. This is why you pay a NA to draw these things... there are no production boats that meet the design criteria.

Actually, I vaguely remember that there were two built in the end, but I'm not sure!

Jim

Yes, but they were trying to sell them i think, i don't think it was intended to be a one off. But i could be wrong, (its happened before)

Steve.

[Polux]

Originally Posted by Delancey

Ran across this interesting looking Class 40 inspired cruiser by Owen Clarke, who comments about the boat which features a lifting keel-

"The client had some very specific requirements and specifications for the vessel, not least the requirement for shallow draft. The first part of the design phase was to analyse the existing Class 40 hull for its suitability and to calculate the mass of the additional cruising fit-out and cruising payload. Fortunately the characteristics of an open type hull very much suit a cruising design in two significant ways: a) the hull is naturally high volume, excellent in terms of space for cruising, b) the large waterplane means that the yacht has far less sinkage (the depth the hull sinks when cruising payload is added) than a conventional hull form. For this client the ability to sail quickly from one cruising ground to another was also of high consideration due to the length of the Chilean coast, distances between harbours and unpredictability of the weather."

40' Blue water lifting keel cruising yacht : Owen Clarke Design - Yacht Design and Naval Architects

Looks good, but Pogo is making already that for some years with a more interesting keel (a swing keel) for a relatively small boat. A lifting keel of that type takes away lots of space on the interior of a 40ft boat, unless what is lifted is only about 80cm and it is not the case with that design.

Have a look at the Brand new Pogo 36 on my blog ( also with a chines and a similar hull).

[Delancey]

Didn't know there was a Pogo with a chine, so thanks for that. Shameless blog promoting noted.

[Polux]

Originally Posted by Delancey

Not sure how well a canting keel would satisfy the design requirements for shallow draft. Didn't know there was a Pogo with a chine, so thanks for that. Shameless blog promoting noted.

Not intended or needed, I mean the promotion, I have about 500/600 hits a day. Just not wanting to post here all those photos. The boat you posted a photo is the 12.50, not the 36 (it is not built it). That one has the hull of the previous Pogo class 40 racer that had already chines. They have now a new40class racer with a more modern hull, with chines two, as all new class 40 or all new solo racers, including mini racers, class9.50 and Open 60.

It you seem you are looking it the wrong way: when the Pogo 36 substitutes the 10.50 there will not be any Pogo without a hull with chines on their catalog (cruising or racing line). The only that has not chines is the 10.50, the older model on their line now.

[clockwork orange]

Looking at that photo of the Pogo it does not seem realistic to me for it to not sail with the chine immersed, I think it would heel fairly easily to that point, then once it is immersed it would stiffen up substantially, but it will be immersed. In light air it should be able to be clear of the water for maximum sail area to wetted surface. Its a great looking boat.

Steve.

[Polux]

Originally Posted by clockwork orange

Looking at that photo of the Pogo it does not seem realistic to me for it to not sail with the chine immersed, I think it would heel fairly easily to that point, then once it is immersed it would stiffen up substantially, but it will be immersed. In light air it should be able to be clear of the water for maximum sail area to wetted surface. Its a great looking boat.

Steve.

Yes I know that the concept of these boats that are designed to sail upwind with little heel is a new one and even if it has been trying with success on solo racers (to the point they all now are designed like that) can be a confusing one.

And that's why you think that chine on the Pogo 36 will be easily immersed and that the boat will go upwind well over it. Well, it can but it is not for what the boat was designed for neither the way to sail more efficiently the boat.

I will post some photos of the Pogo 12.50 going upwind and also a small movie were you can see that the boat is designed to be sailed upwind with small angles of heel. Sure. when that chine hits the water it will create additional stiffness but at the cost of drag. It acts then as a safety feature. When it is sailed over it it does not act anymore and the boat heels suddenly till Max RM pulls it back. You can see that on that video that I posted with the Oceanis 38.







Pogo 12.50 , Chantier Naval Structures on Vimeo

The same designers that developed this concept on solo racing boats, like Finot/Conq, Marc Lombard, Rob Humpreys, Owen &Clarke are now applying the same principles on cruising boats. The things that work making a hugely powerful boat easier to sail by a single sailor works also regarding making a less powerful sailboat being easier to be sailed by Mom and Pa too.

You can see here the same principles applied by Finot/Conq to the design of the Oceanis 41. you can see the similitude in what regards how the hull and chines work and how the boat sails upwind with little heel:





On the Oceanis 38, a more recent boat, Finot/Conq, after the sucess the Oceanis 41 had in what regards sailor's acceptance in what regards the concept went further and designed a boat with more marked chines, a hull that is not far in what regards chine design to the ones they design on solo racing boats. Of course the boat will be more deep on the water and will not plane easily, like a racing solo boat or even a Pogo, but the chines and the hull will work the same way in what regards sailing upwind (with little heel), or limiting dangerous angles of roll downwind. Certainly the several members that have already Oceanis 38 can confirm in a practical way what i am saying here.

[clockwork orange]

Thank you for the photos Polux, they show exactly what i suspected, in every one the chine is just under, rather than just above the water. While i know that what you say is correct as a goal, i just don't think it would be achievable on any kind of consistent basis. The good thing though is that when the chine is immersed it must contribute to leeway prevention. I think it is overall a very good design feature. I would expect that you would actually feel the point where the chine immerses and throttle back much like on a trimaran the amas act as a visual cue. It doesn't hurt that they are great looking boats too. I would think that if you wanted to actually keep the chine clear of the water an inclinometer would be one of your most important instruments.

Steve.

[Cadence]

Originally Posted by clockwork orange

Thank you for the photos Polux, they show exactly what i suspected, in every one the chine is just under, rather than just above the water. While i know that what you say is correct as a goal, i just don't think it would be achievable on any kind of consistent basis. The good thing though is that when the chine is immersed it must contribute to leeway prevention. I think it is overall a very good design feature. I would expect that you would actually feel the point where the chine immerses and throttle back much like on a trimaran the amas act as a visual cue. It doesn't hurt that they are great looking boats too. I would think that if you wanted to actually keep the chine clear of the water an inclinometer would be one of your most important instruments.

Steve.

Steve,

Think you pegged it. Not my bag but probably a good modern design. The analogy to flying an ama was good. You just need to know when to stop the heel.

[UNCIVILIZED]

For anyone who wants the official "High Speed" writeup on Chines, including on both the VOR & Shorthanded racers, plus their cruising perks, here's a link.
taking it on the chin(e) | Sailing Anarchy