Bustle Ahead of Rudder Turbulence

[David M]

There has been one design innovation....


There is a good article about it in this month's Wired Magazine. The author takes a ride in it and goes 54 knots.

[malbert73]

Originally Posted by minaret

I said the same thing here a while back and was roundly mocked for it. Guess it helps to be Bob Perry when voicing such an opinion. The big trend these days is to recycle really old boat design innovations and call them new.

Best fun is reading cruising boat reviews now and seeing the grid where speed is measured in different wind speeds. I swear for most 33 footers they have tested, speeds are nearly identical to what I get on my 1966 vintage cruiser. laws of physics always win....

The big innovations have been on interiors, of course....

[silverp40]

Originally Posted by David M

There has been one design innovation....


There is a good article about it in this month's Wired Magazine. The author takes a ride in it and goes 54 knots.

Mmmm, the outer proa is found in polynesian cultures, sailed and rowed and used for centuries. Maybe not the same sail config or materials, but light generally.

David Lewis has a book (amongst his many interesting ones) called "We the Navigators" which details a few of these designs (no mention of carbon fiber though).

[silverp40]

Quote:

I swear for most 33 footers they have tested, speeds are nearly identical to what I get on my 1966 vintage cruiser.

Ok, but can yours sleep 10 crew inside as in a newer 33 footer? Aha!

[malbert73]

Originally Posted by silverp40

Quote:

I swear for most 33 footers they have tested, speeds are nearly identical to what I get on my 1966 vintage cruiser.

Ok, but can yours sleep 10 crew inside as in a newer 33 footer? Aha!

No, as I noted in the last line of my post.

We have 6 good berths, and the one time we used them all we swore never again on a 33 footer.

[dianaofburlingt]

Originally Posted by malbert73

Displacement sailing is displacement sailing, and until cruising sailboats can plane easily and safely (canting keels??) the fact that they are all "imperfect" ways to travel is unlikely to change.

Thanks for the vote of confidence, Malbert.

I fail to see the drawback in 'displacement sailing'. In fact my take on Olin Stephens' point is that hi-perf sailboats (meaning those that are built primarily for high-end performance) probably make the least-appropriate cruising boats. Of course I'd prefer a cruising boat with excellent performance over anything else. My dad once said that 'speed is safety' --that the less time you're out there, the less chance 'it' can catch up with you (his quotes); and there's great validity in that. Someone criticized the Cherubini 44 for being 'too slack' to carry much in the way of provisions; and my cousin Lee suggested the boat is so fast (and it is) that you don't need as much storage space-- and there's validity in that too.

But 'rule-beater' boats such as the late-IOR types are compromises that don't do enough well; and this is Stephens' point. If you're interested in serious cruising, by all means seek a sturdy, seakindly boat that's designed and built well to start with and has been maintained well over its life. That's just a no-brainer.

I began writing a novel once about a little girl who becomes the youngest to circumnavigate alone (this was before Jessica Watson) and the boat she chose was... a J-27. The idea was that, given decent weather windows, one could make such a cruise almost as a series of shortish hops-- the Atlantic and the eastern Pacific at about 21 days each being the very longest legs. So speed would be of the essence; and a J-27 (a boat I have always liked, rather representing a half-scale Hunter 54) would darn near plane in many conditions. But such a boat would require immense work to make it sturdy enough for those times when the weather window fails (and these parts were in the novel); and therein lies the rub. Most race-oriented boats (and even 'rule-beating' cruising boats, especially of the IOR variety) are not the best performers under sea-storm conditions which one would expect in a long voyage. So we're back to the concept of an intrinsically seakindly hull and rig which can make good time in a majority of realistically-expected conditions; and for that you can't beat something like a Valiant 40 or a C44, either of which can be expected to average an honest 7-8 knots over a 20-odd-day sea passage (and neither of which rates well under IOR!).

(Re: the novel idea-- in the early '70s MacGregor Yacht offered a prize of $25,000 for the fastest singlehanded passage from Long Beach to Honolulu in a trailerable centerboard boat. The winner sailed a Venture 21. )

[Cheechako]

Originally Posted by silverp40

Mmmm, the outer proa is found in polynesian cultures, sailed and rowed and used for centuries. Maybe not the same sail config or materials, but light generally.

David Lewis has a book (amongst his many interesting ones) called "We the Navigators" which details a few of these designs (no mention of carbon fiber though).

But how fast will it be with 3000-4000 lbs of cruising gear? apples and oranges.....

[silverp40]

Quote:

But how fast will it be with 3000-4000 lbs of cruising gear? apples and oranges.....

Faster than the 54kt speedster when loaded with same (more like chickens and papayas...).

[silverp40]

Quote:

you can't beat something like a Valiant 40 or a C44, either of which can be expected to average an honest 7-8 knots over a 20-odd-day sea passage (and neither of which rates well under IOR!).

Average 7-8kts over 20 days sorthanded, 2 or 3 crew?? That is REALLY hard even in tradewind conditions!

[silverp40]

Opening an old thread with the results of the IOR influenced underwater features changed or removed from the stern and rudder of our Pearson 40. I am also including some before and after photos.

The removal of the bustle as well as the IOR influenced gap before the skeg brought some dramatic results to the sailing abilities of our boat. After about 1200 offshore miles in various conditions, here are some results:

Boat handling in relatively large following seas is much easier.
Boat is more directionally stable, especially when beam reaching in larger seas.
Boat is also markedly faster - we never achieved the runs or speeds before as we do now.

Last photo is Before any modifications.

[malbert73]

That looks great! I went back to first post on thread, and compared- looks much more hydrodynamic where it really matters---

Nice work

[robert sailor]

Average speed, no current, for a V40 over 20 days would be 168-192 miles per day...not hard to do.... as it borders on the impossible. Who comes up with these numbers?

[Cheechako]

Originally Posted by silverp40

Opening an old thread with the results of the IOR influenced underwater features changed or removed from the stern and rudder of our Pearson 40. I am also including some before and after photos.

The removal of the bustle as well as the IOR influenced gap before the skeg brought some dramatic results to the sailing abilities of our boat. After about 1200 offshore miles in various conditions, here are some results:

Boat handling in relatively large following seas is much easier.
Boat is more directionally stable, especially when beam reaching in larger seas.
Boat is also markedly faster - we never achieved the runs or speeds before as we do now.

Last photo is Before any modifications.

Sooo.. top two pics are before? I guess what you did was made the hull deeper back there? hard to determine in the pics. (for some reason CF link never allows me to expand the pics)

[a64pilot]

looks like he faired in the rudder to hull, smoothing it and decreasing drag.
Glad it worked out so well. Sometimes though this could have reduced rudder effectiveness, but apparently in this case it was successful.

Love it when a plan comes together

[silverp40]

Sorry for the confusion, but the Bottom pic is Before the nodifications.

Top of rudder was faired closer to the hull which helps a lot with water being chanelled aft versus to the leeward side.

Adding 2' to the back side of the rudder helped increase rudder area and gives it a noticeably more "bite" in the water.

Here is a foto of the rudder before ....