shaft lock

[captden]

Hi all, I was out sailing the other day and the noise from the shaft free wheeling was driving me nuts when I was in the aft cabin. The transmission is a velvet drive so if you leave it in gear forward or reverse it still spins. Does anyone know where I can get some info on a shaft lock or shaft brake, or what you did to stop the shaft from rotating when sailing.

Thanks in advance

Captden

[SkiprJohn]

Aloha Capt Den,
The only solution I really ever tried was to learn to live with it. I've heard of folks using a piece of line wrapped around the shaff and one guy told me he used a vice grips. I wouldn't recommend the vice grips.
There are shaft brakes advertised in all the major catalogs and glossy magazines.
Kind Regards,
JohnL

[Alan Wheeler]

There is a shaft brake available that works off the hydraulic oil pressure the Velvet drive develops. When the box is in neutral, the absence of pressure cuases the brake to grap the disc. When placed in gear, the brake is forced open. I don't know the name or price, I just saw it in a mag. I will have a look later for it and let you know...unless someone knows the name and posts it...feel free someone.

[delmarrey]

Here are some install procedures........................_/)

http://www.sailingseadragon.com/Shaftlok.htm

[cooper]

if you have enough room you can make one by bolting a car disc brake disc at the join between your gearbox and prop shaft and then mount the caliper to suit. A small single cylinder, master cylinder operates it. (Cheap parts from a wreckers) How you set up the controls is dependant on how much hassle you want to go to each time you apply the brake.

[GordMay]

Like these:

[Maddog]

Throw a pulley on the damn thing and hook up am Alt/gen to get some power back out of it. Would this work?

[SkiprJohn]

Aloha Maddog,
Yes, it does work. It is old technology and we've covered this in other threads.
Capt Den,
If you have a folding or feathering propeller you don't have the problem.
I don't like the prop spinning because of the wear on the cutlass bearing and other parts. If I were you I'd do the most low tech solution possible.
Kind Regards,
JohnL

[cooper]

Yep, just like that Gord !! ...Ize dont know howez ya duzz it , but ya sure duzz duzzit.

[delmarrey]

Gord's picture looks good BUT one has to compensate for a diesels shaking and movement. The calipers need to be soft mounted for movement just like on car wheels.

Adapt a motorcycle disc brake assy. Not hard to do with a few basic machine skills. Use the stock front brake master cylinder off the bike, and a brake loc available through most VW aftermarket distributors. I would set the actuator up near the ignition so you remember to release it before putting it in gear.
Or, go with a folding prop.

[Alan Wheeler]

Another idea is to look for manufacturers of boat trailer braking systems. We have one here in NZ called Trojan. The systems are cheap and are designed to be emersed in salt water.