Plumb Bows, Slab Sides, and Wet Decks

[Brob2]

Originally Posted by Delancey

Plenty of TP52's with tillers and tiller extensions. I have a tiller with a tiller extension on my 40 foot cruising boat. Completely practical in every way.

I'm going to disagree. Tillers and ext's on wide powerful boats require a loat of space when tacking and gybing and in many different conditions and thus when sailing with a large crew can be a real pain in the butt, a problem that's lessened with 2 smaller tillers. Crew always have to be aware of where the tiller might go next. Mind you, I have never sailed a 2 tillered boat!

[Polux]

Originally Posted by OceanSeaSpray

Single or twin rudders is not a matter of boat size. If you carry a lot of waterline beam a long way aft, you end up lifting your single rudder half out of the water when the hull heels.
Technically, twin rudders allow the immersed one to work more vertically while more deeply immersed, so it can be made smaller and the one mostly up in the air doesn't drag much. It is more efficient if the stern shape is suitable.
The catch is that the windward one is very exposed wave impacts and any junk afloat pushed aside by the bow wave loves to clip it too. It is a configuration a lot more prone to damage than a single blade in line with the keel. I would have designed my boat with twin rudders if it hadn't been for unlimited ocean cruising. Single rudder limits what you can do with stern shape.

On cruising yachts, i.e. heavier boats than racers, adopting racing stern hull shapes mainly results in more wetted surface and more penalties than benefits in most common sailing conditions. They don't go fast enough, they don't have canting keels to develop the power etc.
Look at the stern quarter view of the Pogo 36 in an earlier post, see how curved the hull is aft: there is very little beam at the waterline aft. Keeping it "flat and wide" would have caused enormous problems with heel. Looks and marketing often have more to do with shapes than anything else and the real challenge can be making it look a certain way without actually screwing it up.

Sorry about making you write so much! Blame it on my bad English. I did not wanted to say two rudders but two tillers

Two rudders have nothing to do with what I said but with big beamy transoms and strongly asymmetrical water planes when the boat is sailing upwind, that I believe it resumes what you are saying.

Regarding cruising boats and chines it depends. On the case of the Pogo you are not right and those chines have a functional purpose and also help to make the boat easier to control but on more heavier and less sportive cruisers chines are there mostly to help on the boat control and a boat easier to control by a small and inexperienced crew is a faster boat. That's why they are used on solo racing boats and not at top crewed boats like the TP 52. If you want to discuss it further there is a thread all about that.

[Polux]

Originally Posted by Delancey

Plenty of TP52's with tillers and tiller extensions. I have a tiller with a tiller extension on my 40 foot cruising boat. Completely practical in every way.

Yes but I believe that they only use a single tiller because the Tp 52 has only a rudder, at least the ones I know. Anyway that huge tiller pole does not seem to me very practical in what regards cruising and even in what regards racing seems to intrude a bit.

On Open solo racers boats the tradition is two rudders two tillers. On the TP52 you have a guy on the tiller, on a solo boat it's one man do it all and the tiller has to be more accessible. This one man do it all is more close to what you have on cruising on most boats, so in a boat with a large transom it seems to male sense to me to follow Open boat type of twin tillers since two rudders is also the more common option. They also intrude less with "passengers" since they are shorter.

[Delancey]

I always used to get a kick out of these boats on Lake Garda. If you look closely in this picture you can see and very thin black tiller extension that looks to be almost three meters long!

[Polux]

Originally Posted by Delancey

I always used to get a kick out of these boats on Lake Garda. If you look closely in this picture you can see and very thin black tiller extension that looks to be almost three meters long!

Yes, incredible boats...but what options they have regarding that tiller extension, narrow boat and all? Funny anyway and when they change tak I am sure it will be needed a lot of training to do it in a smooth way, big extension and all

[OceanSeaSpray]

Originally Posted by Polux

Regarding cruising boats and chines it depends. On the case of the Pogo you are not right and those chines have a functional purpose and also help to make the boat easier to control but on more heavier and less sportive cruisers chines are there mostly to help on the boat control and a boat easier to control by a small and inexperienced crew is a faster boat. That's why they are used on solo racing boats and not at top crewed boats like the TP 52. If you want to discuss it further there is a thread all about that.

Except that all this is theory, suppositions and expectations and there isn't a single body of evidence to demonstrate that the little kink in the side does actually achieve all this. When it comes to "boat control", I could list you a great many other influencing factors that dwarf completely the supposed potential difference a small chine might or might not make!
When people do something unusual, they feel they need to explain it. Even if they can't. Saying "I am just trying this to see what will happen" doesn't cut it. So they build a pyramid of justifications.

Some chines above the waterline can deflect water in the right circumstances, and they tend to cause added drag when immersed. Besides that, they open options to change hull volume distribution and stability for the heeled hull.

Now the thread has drifted completely off topic, so that will be it for me. If you think the little chine is performing magic and I am completely wrong, why not? I design and analyse hulls and marketing is based on having a point of difference.

[Polux]

Originally Posted by OceanSeaSpray

Except that all this is theory, suppositions and expectations and there isn't a single body of evidence to demonstrate that the little kink in the side does actually achieve all this. When it comes to "boat control", I could list you a great many other influencing factors that dwarf completely the supposed potential difference a small chine might or might not make!
When people do something unusual, they feel they need to explain it. Even if they can't. Saying "I am just trying this to see what will happen" doesn't cut it. So they build a pyramid of justifications.

Some chines above the waterline can deflect water in the right circumstances, and they tend to cause added drag when immersed. Besides that, they open options to change hull volume distribution and stability for the heeled hull.

Now the thread has drifted completely off topic, so that will be it for me. If you think the little chine is performing magic and I am completely wrong, why not? I design and analyse hulls and marketing is based on having a point of difference.

Yes, but as I had said to you there is a thread all about that. If you want to discuss it you may want to go there. Regarding this: "Except that all this is theory, suppositions and expectations and there isn't a single body of evidence to demonstrate that the little kink in the side does actually achieve all this. " You may rethink about that. All top solo racing boats have chines. That does not ring a bell in what regards efficiency towards a better controllable boat and therefore a faster boat? It is not evidence enough that all best NA that work with CFD, VPP and a lot are using them on solo racing boats? It is not evidence enough those boats are always faster on the race track?

[downunder]

Originally Posted by OceanSeaSpray

Except that all this is theory, suppositions and expectations and there isn't a single body of evidence to demonstrate that the little kink in the side does actually achieve all this. When it comes to "boat control", I could list you a great many other influencing factors that dwarf completely the supposed potential difference a small chine might or might not make!
When people do something unusual, they feel they need to explain it. Even if they can't. Saying "I am just trying this to see what will happen" doesn't cut it. So they build a pyramid of justifications.

Some chines above the waterline can deflect water in the right circumstances, and they tend to cause added drag when immersed. Besides that, they open options to change hull volume distribution and stability for the heeled hull.

Now the thread has drifted completely off topic, so that will be it for me. If you think the little chine is performing magic and I am completely wrong, why not? I design and analyse hulls and marketing is based on having a point of difference.

OceanSeaSpray

You will never out post Polux even if you are correct.

Seems that at similar waterline the expensive fat asse of Commanche had too much drag for it to beat the narrow hull of Wild Oates in the recent Sydney to Hobart. Any comment?

[Polux]

Originally Posted by downunder

OceanSeaSpray

You will never out post Polux even if you are correct.

Seems that at similar waterline the expensive fat asse of Commanche had too much drag for it to beat the narrow hull of Wild Oates in the recent Sydney to Hobart. Any comment?

That was predictable given the conditions. In fact I predicted it on my blog. Post also about why and posted an interesting movie comparing the two hulls. That's fantastic how to different hulls can have such a close performance....but we are not talking about solo racers

[OceanSeaSpray]

Originally Posted by downunder

OceanSeaSpray

You will never out post Polux even if you are correct.

Haha, I don't think I could be bothered doing so! My interest is in hull design and sea-keeping, not hull arguments. I said that plugging a racing yacht "feature" onto a cruising design doesn't result in a better boat - they just don't function the same on the water, the dynamics are different - yet I am getting told stuff about social proof and top racing designs!



Pushing water at the bow?



Turbulence off the stern?

It would all be looking much better if it was doing 15 knots, it is just that it doesn't. Now add a couple of tonnes of cruising gear on board and have another look. Take it for a beat in a short steep sea.
Design for the sea and the most common sailing conditions, not the rare or unlikely exception, the boat show and the magazines.

Yet we now all need a little kink in the sides to look up to date. Funny also that the Pogo 10.50 doesn't have that critical little chine.
I don't have one either, my hull is as dry as anything and I have had it holding 14.5 knots cruising single-handed with two fingers on the tiller catching up with the waves in front of me - fully equipped offshore cruising yacht with a tonne extra on board at the time. And I can turn around without everything going slam-bang - there has got to be something wrong clearly!

[Polux]

Originally Posted by OceanSeaSpray

Haha, I don't think I could be bothered doing so! My interest is in hull design and sea-keeping, not hull arguments. I said that plugging a racing yacht "feature" onto a cruising design doesn't result in a better boat - they just don't function the same on the water, the dynamics are different - yet I am getting told stuff about social proof and top racing designs!



Pushing water at the bow?



Turbulence off the stern?

It would all be looking much better if it was doing 15 knots, it is just that it doesn't.

Yes it does. I have a friend that has a Pogo 12.50 and 15K are attained even with cruising gear on board. The ones that sail and have those boats cruise light because the like speed and the fun of sailing that way. This is a Pogo 12.50 charter boat.

https://www.youtube.com/watch?v=eUxe3YmKgvs

They are sailing it baddly without any front sail and too much mainsail and even so the boat does not complain and keeps going without broaching. The big stability and those chines have something to do with that.

The hull of that cruising boat is the same of the older version of the Pogo 40class racer and you can believe that if that bow and stern works for winning races they work also for cruising very fast.

Originally Posted by OceanSeaSpray

Yet we now all need a little kink in the sides to look up to date. Funny also that the Pogo 10.50 doesn't have that critical little chine.

The Pogo 10.50 is an older design from the time chines were not yet used by all solo racers. The Pogo 36 is a new design and therefore the designer improved the old design in several aspects, one of them chines. The designer is the same, Finot/Conq. They have an huge experience with racing solo boats and chines. They used them first in racing solo designs, now in cruising ones too.

[OceanSeaSpray]

Originally Posted by Polux

Yes it does.

My friend, those ones, on the pictures, are clearly not sailing at 15 knots and I have no doubt that one can sail them at that speed when the conditions are right and provided there isn't too much gear on board.

In the meanwhile, they still appear to be pushing water and dragging the transom. Design for the average conditions, not for the exception people will be talking about.

[Polux]

Originally Posted by OceanSeaSpray

My friend, those ones, on the pictures, are clearly not sailing at 15 knots and I have no doubt that one can sail them at that speed when the conditions are right and provided there isn't too much gear on board.

In the meanwhile, they still appear to be pushing water and dragging the transom. Design for the average conditions, not for the exception people will be talking about.

What I can assure you is that the Pogo 12.50 has a IRC rating ridiculously high and that is faster on most conditions than any other performance cruiser of the same price. Only Carbon cruiser racers, used almost exclusively for racing will be a match for it in what regards speed potential.

I do not even prefer that particular type of boat for cruising (and I like to cruise fast) but reality is what it is, pushing the bow water or not.

[downunder]

Originally Posted by Polux

Yes it does. I have a friend that has a Pogo 12.50 and 15K are attained even with cruising gear on board. The ones that sail and have those boats cruise light because the like speed and the fun of sailing that way. This is a Pogo 12.50 charter boat.

They are sailing it baddly without any front sail and too much mainsail and even so the boat does not complain and keeps going without broaching. The big stability and those chines have something to do with that.

The hull of that cruising boat is the same of the older version of the Pogo 40class racer and you can believe that if that bow and stern works for winning races they work also for cruising very fast.



The Pogo 10.50 is an older design from the time chines were not yet used by all solo racers. The Pogo 36 is a new design and therefore the designer improved the old design in several aspects, one of them chines. The designer is the same, Finot/Conq. They have an huge experience with racing solo boats and chines. They used them first in racing solo designs, now in cruising ones too.

Looks like a club racer for me. Extremely uncomfortable for cruising and on shade or protection and no hats on anyone. Would not last 5 minutes in the tropics.

Not my type of boat - not a club racer.

[Polux]

Originally Posted by downunder

Looks like a club racer for me. Extremely uncomfortable for cruising and on shade or protection and no hats on anyone. Would not last 5 minutes in the tropics.

Not my type of boat - not a club racer.

Yes I believe it is not your type of boat, neither a club racer but a performance cruiser. If you want to race Pogo makes racers too (Mini racer, 40class racer).

With a Pogo cruiser you will end last in almost all club races that are handicap races. The boat has a lousy handicap and was not designed for that but just for the ones that like to cruise really fast, long range cruising too.