516Re: [AtkinBoats] Re: Most Efficient Hull??
- Jan 17, 2005Manfred:
I have read your postings here (and, I think, in other boat design forums). As you seem to have access to tank testing facilities, I wonder if it would not be a worthwhile project to take the Sea Bright tunnel stern hulls - which Atkin designed in many lengths - and model them for tank testing (for the modern builder, probably the designs which could be built of plywood would have the most interest). There is a desire to have stable, shallow draft pleasure boats that will cruise comfortably in the 15 - 18 mph range (ask any family which has a 30+ mph plastic boat and you'll find - after they've owned it a year or so - that comfortable, non-pounding would be welcomed, even if at a decreased speed). I believe that the tests would show remarkable efficiency, seakindliness and seaworthiness.
I would think that there would be a large base for these designs in Europe with it's many river, lakes, and canals - and with fuel costs much higher there, an efficient hull using less power would seem a potential "best seller". The Atkin tunnel stern Sea Brights are not well known even in the USA, so probably not at all in Europe.
Sometime this year I expect to start work on an adaptation of Rescue Minor, but mine will be powered by a reasonably compact steam plant with normal crusing at 1000 rpm (although 2000 rpm will be possible). The shallow draft and "beachability" as well as ease in trailering and modest weight are just what I want for cruising on lakes, rivers, and the occasional trailer from Portland, OR to Puget Sound. I've lived on and around the water most of my 65 years and spent the last 3+ years searching for the "right" design for my needs and desires. I believe the Rescue Minor is it (Thanks, John, for setting up the AtkinBoatPlans website - I probably couldn't have done it without you!).
----- Original Message -----
Sent: Monday, January 17, 2005 11:29 AM
Subject: [AtkinBoats] Re: Most Efficient Hull??
Describing "River Belle" the 35'3" Tunnel-Stern River Cruiser William
Atkin writes : " The hull is easily propelled and for equal
displacement and power is faster by several miles than the usual
underwater form. And these boats ... handle perfectly,ahead,astern
in rough water or smooth ." The first boat of this model was designed
already in 1922 !!!
At this time most of the boats had semicircular displacement hulls
with l/b ratios up to 1/7 ( and more ) and were difficult to build
with big and heavy motors throwing big bow waves and rolling heavily
in a seaway. Later on hulls of Cats and Tris were constructed in a
similiar way with semicircular bottoms and with hardly any
hydrodynamic lift when moving.
>From this point of view William Atkin was a Genius and a
Visionär ( german Language ) as he knew a lot more of the water
around his boats as others up to our days.
>From my personal experience watching University tank tests I think
that the "Sand Piper" design also is very effective. And this is the
same for the Higgins Landing Boats which helped to end the Nazi
I think that these hulls deserve to undergo intensive tank testing
to understand fully the Atkin designs and to minimize the vortices
(whorls ?), waves and eddies caused by the hull moving through the
water.In my opinion these hulls have a great potential of
hydrodynamic efficiency. Regards, Manfred
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