Liftable propulsion sistem !!??

Hello to everybody!
I found some wooden fishing boat plans : http://www.fao.org/DOCREP/003/W7260E/W7260E02.htm#ch2.4
with liftable rudder and propeller ! I want to build a boat like this. Nows enybody how this installation is function, or has maybe some plans of it ?
best regards Szakats Attila

 

It's called an "outboard engine" and you can buy them.

Look at:

Johnson
Mercury
Yamaha
Seagull

and many more

 

WoodenBoat magazine had an article in one of its recent issues on an old system using an air cooled engine. It is direct drive, and has a joint in the output shaft so the prop can be lifted into a recess in the hull. If you want something unusual there should be some old plans out there. If you want performance and reliability use an outboard.

Gary

 

If you access The London Patent Office and search for the patent No 1,114,794 Complete Specification published 22 May 1968 Improvements in and relating to Motor Boats and the mounting of Power Units there to,you may have the plan possibly from which the Food and Agriculture Organisation developed the fishing boat design from.the drive consists of a toeque tube containing a shaft the rear end of which you can see in the plans.The front end of which is pivoted like a see-saw near the motor which is mounted on top of the torque tube facing forward and driving the propeller shaft from a pulley on the motor and propeller shaft.This unit is fitted into the boat hull in a slot sized to carry the unit,much like a centre board fitting.This system is suitable for small motors.The exit of the torque tube into the hull would need to be above water level of the hull.No water seals are shown in the plans.There must be many other versions used elsewhere.

 

The Lunenburg Foundry, Lunenburg, Nova Scotia, Canada used to manufacture a lifting shaft and propeller setup for beachable dories. I am unsure of whether they still make them. If not you can E-mail Kim Smith at "The Dory Shop In the same town. He builds them and if anybody on the planet knows where to get one, he will.

 

Hallo Gary!
Thanks for the answer! You have right, i want some unusual, no performance. i have 3 outboards. Have you this article,can you send it to me?

best regards SZ.A.

 

Hello Tom!
I don't found anything at this patent no, at this date, in the arhive of "The Patent Office" ( http://gb.espacenet.com/ ). have you access to the documents you mentioned? Can you give me the exact location of it? Thanks and best regards SZ.A.

 

SZ,
I'm sure I can find it. I'll look when I get home.

Gary

 

Can't find it, now I'm not sure where I saw that article. I'll keep looking.
Gary

 

S.Z. I have also seen the article in wooden boat. Issue 171 has an interesting design. Danella, A Louisiana duck-chalon. March 2003. Mean while I'll keep searching

Good Luck.
Kyle

 

Here is a link to another type of the same idea.
http://www.disappearingpropellerboat.com/history.html

Gary

 

High Szakats Attila.My search information on this subject is before the internet.I will try to digitize it for posting.Is not history very interesting.There are other interesting inovations like this idea.

 

Thank you guys for the trouble you've taken. I take a look to the "dissappearing propeller boat" , it's nice but it is not the same device.I want to make a boat with an inboard motor (maybe a steam engine), but our river (Tisza) is in some places shallow. I am thinking about the 8.5m (28ft4in)whit possibilities to sleep in the boat.
best regards Attila

 

Liftable propulsion

In France, on the north Brittany coast, boats with liftable propulsion are used
for harvesting algae. The tides are very high ( until nine meters...), these small boats work slaloming in the middle of rocks and have to beach for discharging the algae.

As I have seen on one boat the liftable propeller device is simple; The installation of the engine and gear boat is classic but the shaft, after passing through the hull, has a joint or cardan. The support of the bearing of the propeller slides vertically between 2 rails, an hydraulic cylinder adjusts the height of the propeller. A small keel protects the propeller while being in "up" position. The propeller protudes from the stern.

I have read, a long time ago when my beard was black, about a system used with small diesel 5 to 12 HP engines: The engine is installed a frame that rotates on a transversal axle. The shaft is contained in a pipe bolted to the frame. The pipe passes through the stern by a slot above the water. The heigth was controlled by a screw and a wheel.

If you need I can make you a rough drawing. It's very simple and would work with small power without problems.

 

A small research in the FAO site and...

The link for the FAO liftable propulsion is:

ftp://ftp.fao.org/fi/document/pdf_zip/ad531e.zip (size; 2.293 Mb)