Anyone got a shaft brake on propeller shaft?

dansar

dansar

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We have a propeller shaft which rotates, when under sail and engine switched off, and are looking into the fitting of a shaft brake. The gearbox is hydraulic and the shaft continues to rotate even when astern gear is engaged.

So has anyone got a shaft brake and if so is it DIY or can you buy one off the shelf? /forums/images/graemlins/confused.gif

Thanks

David
 
Thanks for your reply.

I should have said the yacht is 22 ton long keel with a fixed 3 bladed propellor and a folding prop, so I've been told, would not be suitable.

Thanks

David
 
I read somehere that if you have a (hydraulic) coupler on a gearbox then a shaft brake should be fitted as the shaft going round whilst just sailing could make a pressure build up in the gearbox. That being the case I would have thought your yacht would have had one fitted already. /forums/images/graemlins/smile.gif
 
Previous owner had died and no paperwork available from family. On the internal part of the shaft is a pulley which from investigation, was attached via a belt to an alternator which in turn provided a trickle charge to the batteries whilst the yacht was under sail. But the experts on gearboxes state that you can create problems if sailing for long periods, which we intend to do.



/forums/images/graemlins/confused.gif

David
 
Bruntons or Lancing Marine...

There's a clever automatic shaft lock for hydraulic gearboxes, called the Autolock, made by Bruntons (the propellor people). Expensive though!

Alternatively, you should be able to get a cheaper shaft brake from Lancing Marine. There's a US unit called Shaft Lok, but this requires you to slow the boat down considerably before it will lock. To resolve this problem, there's a newer product called Easy Lok, which operates slightly differently. Both of these allow the propellor to be stopped in the best position (whereas the Brunton Autolock just works like a car disc brake and the prop position could be anywhere).
 
Re: Bruntons or Lancing Marine...

Here's the one fitted to Mirabella V, though I don't think it was a DIY job
M50071_s.jpg
 
Hi, not sure if i can help but i have seen some disc brake conversions done on Land Roer gearboxes which usually have a drum brake on them, they brake the propshaft - not the wheels directly. A disc can be made from a flat sheet turned in a lathe and a caliper can be had from the rear of some cars with disc braked rear axles, they may be cable operated or for much more power use any disc brake caliper and a simple master cylinder and lever brake like a rally car handbrake. I believe demon tweaks sell a purely cable operated caliper which is another option. I wouldn't know how to mount the disc to the shaft but i'm sure someone could think of something?

Might be way off but thought i'd offer an opinion.
 
OK her is a cheap and cheerful way do solve the problem...Grip the prop shaft with a mole wrench..BUT ...in such a way that the release lever for the mole rests against a solid part of the hull,or a wooden block etc so that if you forget to release the mole before starting up,it will release itself automatically. This method needs a bit of imagination and ingenuity but it works every time..EXCEPT! ...if you go into reverse first..but would you ever?
 
When you go below to check that the shaft is stopped in the correct position To hide in the turbulence of the shaft log 'tis normally a simple matter to insert a large screwdriver or tommy bar in the coupling so that it jams against a convenient stop. One could always rig a withdrawing line to the deck so that the engine could be re-started in an emergency alternatively leave the engineer on watch in the engine space with a large pair of molegrips.
 
I own a 13 ton Hillyard. She also has a shaft brake but the previous owner removed it as it destroyed itself by being left on when the engine was started and put in gear. He did not get around to replacing it and it seems to have gone missing. However I spoke to Spencer Carter who were the original manufacturers and they were extremely helpful. Basically the shaft brake consisted of a brake disk attached to the shaft and a brake caliper mounted on a bracket appropriately. The brake was actuated by hydraulic cable. The best bit about this was that the caliper came from the front of a Triumph Herald, and they are still available to day. They are not expensive which is rare in boating nowadays.
 
Here is an idea that comes to mind. If you have a pulley fitted already then a piece of rope pulled tightly up into the pulley goove may stop it turning. I suggest that you anchor one end of the rope and attach a small tackle to the other end to get some pressure. Now it might not stop the prop although it might do the job if the boat is going slowly when applied. The rope of course may wear out quickly but then I am sure you have lots of spare rope. I think it wouuld be worth a try. If it is inadvertently left applied it probably would do little harmm. Maybe wear out the pulley you don't use anyway. good luck olewill
 
Thanks to everyone who has posted a reply. Some interesting DIY options /forums/images/graemlins/shocked.gifand some expensive ones available to buy. /forums/images/graemlins/crazy.gif

I'm going to have to wait until I'm next onboard to see what the best option will be.

Thanks again

David
 
To Rex

A friend of mine, who is a retired marina engineer, said that a constant rotation, without the engine running, of the shaft can cause numerous problems, let alone extra wear. I'm sure there are plenty of "experts" on this forum and I'm just trying to find out what is going to be the best for the shaft. Having sailed for over 30 years, our yacht is the first I have sailed on where the shaft continually turns.

Thanks for your post, and hope this answers your question.

David
 
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