Hickman's First Published Discussion

[DogCavalry]

Professional Boatbuilder reprinted the very first article ever written on surface piercing propellors: Hickman's 1911 article in The Rudder.

Hickman's Imagination and the Dawn of Surface-Piercing Props - Professional BoatBuilder Magazine https://www.proboat.com/2019/03/hickmans-imagination-and-the-dawn-of-surface-piercing-props/

It's a great read. I'm particularly struck by how robust the idea is. It worked well, the first time, despite the terrible conditions.

J

 

[BlueBell]

PS It's frustrating to be unable to correct my poor spelling in the thread title. Oh well.

Isn't it though!
I've done the same thing too.
Funny, I didn't even notice until you pointed it out!

 

[Boat Design Net Moderator]

When that happens, please click "report" under the first post and leave a quick note identifying the typo. Thanks!

 

[DogCavalry]

How about the part where he didn't have the gear they needed, so they plunked the one they had into the sand, cast another from that, and let the two of them grind each other down into a functional fit.

 

[DogCavalry]

Paul Kamens 1995 paper discusses surface drives for low speed and displacement vessels. If Hickman got great thrust at 15 mph, obviously the lower end of the envelope needs more research.

 

[DogCavalry]

Just reread the other day. His first test was a pair of 22 inch props run by a single 17 hp engine, on a 20' boat made from fence boards like a box. It leaked so bad theyhad to pump out the water every few runs. The props were turning 800-900 rpm. He made 18mph.

 

[BlueBell]

18 mph with 17hp on a 20' boat, that is impressive.

So, basically, two, ~10" blades pushing at a time...

 

[DogCavalry]

I couldn't remember how to calculate the area of an arc segment, so I used an online calculator. A 9" arc segment from a 22" diameter prop has an area of 146²". So 2 of them are worth almost 4 10" props in simple disk area. But the 10" props would include hub an blade root area, so more than 4. Those were very lightly loaded props. No wonder it was so efficient.