Some Q on Stabilizers.

[FAST FRED]

"After a proving and use period, the " secret " is released to industry. "

Since there is NO secret to building a reliable pump motor , And UNCLE will have paid for the design AND for the machenery to produce the unit , simple excess capacity will provide the parts for boaters soon enough.

May be a while for Surplus Sales and really low cost , but a year is a long time today for a mfgd product.

FAST FRED

[cyclops]

D'ARTOIS, how long have cruise ships had roll fins ? As I recall they used to dock at special piers in NYC.

[cyclops]

Electric motors and there relatives, linear and or induction magnet, are moving high speed trains all over the modern world. They stop at the same spot on train platforms everytime. A hyd. system is very bulky lots of parts, huge elect. motor, pump unit, resevoir, valves. piping, cylinders,etc. Loads of wasted energy and heat from the elect. motor and hyd. pump and the stroking of the cylinders. High frequency inverter motors run at up to 93% eff. 5 years ago. Few new applications for oil in the hi-tech world. $$ is killing them compared to a controller and one motor or step linear magnet. Only 2 parts to replace. I know, I am a Dinosaur.

[fcfc]

At least, pneumatic actuated ones do exists:
http://www.stabilizers.nl/site/index...lizers&lang=uk
http://www.gyrogalestabilizers.com/index.html

Given the air requirements (16 cfm for one, 10-17 cfm for the other) the max hp should be around 4-6 hp. Including compressor losses.

For electrical ones, the main questions is how to estimate the rotating torque I need. I can know the maximum torque with any rudder torque calculation, but rudder actuation is slow compared to stabilzer fins.

What is also the typical rotating speed of fins.
Heard about +- 20 ° max travel in one second. But that related to cargo size, not a 50 ft powerboat.

[cyclops]

Do you really believe a 600' loaded ocean freighter whips back and forth every second ? Now a small 50' going sideways over the crest of a wave, maybe. A big 50' is unaffected.

[fcfc]

Originally Posted by FAST FRED

A 2 hp hyd motor is a one hand lift , 2hp DC in 24V would weigh a hundred pounds!

FAST FRED

Look http://www.torcman.de/shop/index.htm..._30_PRO469.htm

The 1500 W version (2 hp) is 2 1/2 " len, 2" diam and and a little over ONE lb.

OK, I admit these are special electric motors, but industrial rated ones are twice or three time heavier, maybe ten. We are very far from an hundred.

Permanent magnets and power eletronics have done tremendous improvements in the recent years.

[mareng]

If anyone is still interested in this subject, I might be able to offer a bit of insight.