Hickman Sea Sled - Inverted Vee

[ClarkT]

I know this hull shape has been around for years, but I wonder if anyone knows of any published research on this hull form. Or, lacking that, anyone care to talk about their experience with dynamic instability of this hull form, and how it might be improved?

[duluthboats]

Read all posts from badges65 and check his site. That would be a good start.

http://invertedvboats.20m.com/

Gary

[ClarkT]

Gary, thanks for the link. It's a start, but Don really does a great job hyping the Inverted Vee without acknowledging its weaknesses. I've found in model tests that the inverted vee hull form is stable at level heel, but also quite stable at a large heel angle. I've heard of similar problems at full scale. I wonder what is done to solve it, and what are it's causes.

[duluthboats]

“I've found in model tests that the inverted vee hull form is stable at level heel, but also quite stable at a large heel angle.”

I’ll assume you intended to say unstable. I think I would agree, but isn’t that also the case for other narrow cats. I have no experience but I can envision it tripping over that sharp edge in the right conditions.

Gary

[ClarkT]

"I’ll assume you intended to say unstable."

No...it is stable and tracks straight at 30 degrees of heel. Then a little helm or a wave knocks it, and it swings upright and tracks level until something else sets it off and it becomes stable heeled again.

http://www.breammaster.com/forum/sho...&threadid=4775

This thread about an alloy invetered V being built downunder.

Both Don and I have some input to the thread along with the civil engineer building it.

I'm of the opinion fitting a hysucat style foil - and canting twin outboards to vector the thrust to make it heel into a corner will make a different boat out of it. I also think the thrust vectoring will take the heeling tendency mentioned above out of it while travelling in a straight line,

Interesting to hear what others think about that idea!

Cheers!

[gonzo]

The US Navy tested them in the 40's and then again in the late 70's. They found that the speed to HP compares to a hydrofoil with more stability and seakeeping abilities.

The following is a incomplete list of patents that were taken out by Hickman. Listing is US patent followed by the same or equivalent

patent as taken out in another country - shown in brackets (). US=USA, CA=Canada, AT=Austria, DE=Germany, GB=UK(GreatBritian), FR=France.


US1044176 ( AT64415, CA159692 )
US1204355 ( AT93970, DE385609, GB19153951 )
US1553160 ( CA275010, GB240470 )
US1553161 ( CA275011, DE478369, FR603499 )
US1620349 ( CA271328 )
US1621839 ( CA271329 )
US1644725 ( CA271324, GB207775 )
US1670622 ( CA271325, GB209700 )
US1670623 ( CA271327 )
US1681342 ( CA271326, GB209699 )
US2515005

All the above, except CA159692, are available for free from the following websites:

Canadian Patents Office:
http://patents1.ic.gc.ca/srch_adv-e.html

US Patents Office:
http://www.uspto.gov/patft/

European Patents Office:
http://ep.espacenet.com/

German Patents Office:
http://www.depatisnet.de/

UK Patents Office:
http://gb.espacenet.com/

The most interesting hull is shown in US2515005 where Hickman shows how he alleviated the majority of the disadvantages of sea sleds.

A plan for an inverted v hull sailboat called "Sea Mite" was published in "Science and Mechanics" and "Boat Builder Handbook" as Craft Print Project No.324. This appears to be based on Hickman's sea sled design.

It is downloadable from:
http://www.svensons.com/boat/?p=SailBoats/SeaMite

Correcting a mistake:

Patent CA159692 is same as US1204355 not as per previous post.

[Rik van Hemmen]

I was involved in the design of a modern version of the sea sled.

These designs were developed in connecticut in 1987, 1988.

I had particular experience with a 28 footer.

This was a recreation of one of hickman's later designs that uses the exterior chines.

When looking at the transom, you would see an outboard chine about 12 inches wide with a deadrise angle of a few degrees at the transom, gradually increasing going forward, a vertical step like a spraystrake and a flat centerline bottom about 6 feet wide.

The boat ran with twin 150 yamaha outboards and was very fast and accelerated like a scared cat.

We also had one with a single mercruiser, but I don't recall running that boat.

We never had any running problems, and the boat controlled well. It was a surprisingly good searide, but not straight into waves. Never had control problems going down wind (no dutch roll) The one problem was porpoising at high speeds (around 50 mph), but when we fitted a trim tab at the flat part of the transom the porpoising disappeared.

They were impressive boats and in certain applications might be the perfect hull shape. For a planing boat they had great weight carrying capacity and low wake. In New York they run planing hull passenger ferries, and I have often thought that a seasled hull would be much better in that application.

[erichise]

Originally Posted by ClarkT

I know this hull shape has been around for years, but I wonder if anyone knows of any published research on this hull form. Or, lacking that, anyone care to talk about their experience with dynamic instability of this hull form, and how it might be improved?

-====================================================

I recently bought from auction a 1920's Hickman SeaSled double cockpit; barrelback racer. It is in remarkable original seaworthy condition. What type of hickman do you have? mine is 22' and designed to move @40mph while drawing 1 ft of water. I have several pictures available. I too am looking to get info on the design.

[erichise]

I recently purchased a 1920s Hickman SeaSled in remarkable original seaworthy condition. The hull is inverted VEE; with step down hull design. The boat is fitted with 2 large rudders, and one 24" tri blade prop. I can not stress the original condition. In fact, it appears to have the original factory varnish and paint scheme. The boat was owned by a local Hickman boat dealer from the 1920's, and was in storage since 1948. Please contact me if anyone has imput . Rgds, Eric Hise....Genoa, Ohio 43430

[SeaDrive]

Phil Bolger published comments about the Hickman types in a recent issue of Messing About in Boats. His view, summarized, is that you can get a better boat using other shapes.

Originally Posted by SeaDrive

Phil Bolger published comments about the Hickman types in a recent issue of Messing About in Boats. His view, summarized, is that you can get a better boat using other shapes.

Since I am not a subscriber to MAIB, I have been unable to read Phil Bolger's column regarding his comments about sea sleds.

Would you be so kind as to summarize for us nonreaders of MAIB what uses the sea sled hull shape could be used for, not forgetting there appear to be three hull shape variations - a) inverted-v all the way to the transom (1910s onward), b) flat at the transom (1920s onward), and c) flat at the transom with stepped outboard chines (1940s onward).