Rescue minor: new light

[Spokaloo]

I was poking around another forum and came upon this thread:

http://boatdesign.net/forums/showthread.php?t=20520

One of the ideas discussed is how RM's hull somehow manipulated the boundary layer of water into the tunnel and created either a nozzle of sorts, or an accelerated area of water to press against, thus creating efficiency. Personally, given the thickness of the boundary layer (2" or so in a boat that size) I thought it was goofy.

Another forumite put out the idea that some of the RM's were more efficient than others, specifically the Robb White version. Robb's was extremely light for her size, and had astounding performace numbers ( 12-17 kt speeds and an astonishing 21nmpg). His reasoning is the RM Robb built basically had the characteristics of a displacement glider and didn't require much in the way of displacement from the bilges or lift for that matter, as the box keel handled most of the displacing. As anyone knows, you can smash a long, narrow hull through the water much faster than its hull speed, and this might be a good indicator.

Point being, if you get this project in hand, and it is built lightly enough, can one expect something on the order of those economies of fuel? Is there agreement that its basically a DG? That would make a redesign very popular, esp if empirical data can be pulled of a completed boat.

E

[gk108]

Well, it's pretty well known that Robb White valued his privacy. I live in the same county as that he did, but I never realized that until after he died. I would really like to find out what happened to his RM, but have no idea how or where to start.

[chicagoross]

Spokaloo, you've never wasted any time planning, building, or thinking about conventional boats, have you? Always something interesting but different. I don't think you'd be happy with a bayliner.

[Spokaloo]

My good friend here is the son of the former plant manager at Bayliner north of Seattle. The answer is no.... If I wanted a boring snot boat, I would have bought one. Family owned several boats in the past, A local company called Barron, Mastercraft, and small aluminum. None of them really captured my interest.

Gk, Robb's son still owns the famed RM he built, and to this day uses it. Im not exactly sure where he lives specifically, but I can find out for you if you wish. His name is Wes

E

[jacquesmm]

Weight is a major factor in efficiency and since our material is light and strong, we can count on similar or even better performance.
As for computer modeled speed prediction, that would be nice but way too complex. We'll use experience instead.
I have a good idea of the parameters involved including water path along the hull, intuitive fluid dynamics.

We should remember that the RM is an evolution of hull type on whihc Atkins worked for many years.
He started with the Sea Bright skiff, refined the model then, with more HP in them and to correct the trim, he began to use a built in trim tab in his hulls. That reverse rocker is very visible in some of his line plans.
That reverse rocker with the box keel of the Sea Bright naturally evolved in the tunnel type described and used by Dave Gerr in Summer Kyle..

In the late 70's, I saw the first hull of that type and was very doubtful about the performance until I had the opportunity to test such a hull. Combined with light weight, it is a winner. Unfortunately, it looks so unusual that the type never gained acceptance.

[Spokaloo]

Unfortunately, it looks so unusual that the type never gained acceptance.

Until you redrew it and we broke the 20nmpg barrier....

E

[Boomer]

Just as a footnote, if you've ever heard Bailey White do one of her little pieces on public radio; she is Robb White's sister and a kindergarten teacher.

[gk108]

Gk, Robb's son still owns the famed RM he built, and to this day uses it. Im not exactly sure where he lives specifically, but I can find out for you if you wish. His name is Wes

E

If it's not too much trouble, just send me what you find via my email button.


The more I ponder this, the more I wonder about the differences in a RM built as drawn by Atkin and one with the radical tumblehome like Robb White's. That tumblehome had to lighten the rear of the hull a good bit. Is it lighter hull in general that makes it so efficient or is it lighter hull with (I guess) a change in LCB from the tumblehome that does it?

[Spokaloo]

Go to the woodenboat forum, he is a member there and is reachable. A simple site search will poke his name up.

Its all about light weight. I dont know that the tumblehome would alter any buouancy characteristics, but it sure makes for a very strong structure to have all that curvature. Gets away with less framing as well.

E

[anonymous]

Would anyone care for the stations of a Rescue Minor? I am building her of cold molded sandwich foam and the forms are available. I'm in Florida on the east coast where they can be picked up for a nominal fee.