Split Pulley ?

[W.olly]

Anybody know of any suppliers in the UK.

It is for clamping around a boats inboard prop shaft. Not for me but a mate. he doesnt want to split the shaft.

cheers

Wolly

 

[wookie]

I'll ask at work tomorrow if no one else beats me to it.

 

[Rig Pig]

Can I ask what For?

 

[W.olly]

Can I ask what For?

certainly can.

He wants to run an alternator of the prop.

 

[500e]

Have made split pulleys years ago out of Alloy with a plastic liner to isolate alloy from steel shaft. think i used 6061 ally

 

[CompoSimmonite]

You can get split sprockets for go karts so what about chain, rather than belt, drive ? Problem with a split pulley is he'd still have to remove prop shaft to attach a standard type drive belt. At least with chain you could have split link

 

[CompoSimmonite]

Another idea is attach a small rubber tyred wheel to the alternator and have friction drive on the prop with a spring that kept the tension.

 

[normspanners]

You can get split sprockets for go karts so what about chain, rather than belt, drive ? Problem with a split pulley is he'd still have to remove prop shaft to attach a standard type drive belt. At least with chain you could have split link

not if he uses nutlink

 

[normspanners]

http://www.scag.com/splitsteelpulleys.html use 4bolt type, then cut in half through dia make two bearing shell type flanges to go round the propshaft, drill and tap the flanges longitudinally to suit the pulley hold the flanges around the prop with the bolts, but with the four separate pieces opposite to each other to line it all up ' run two equal jubilee clips together and round the flanges to clamp the flange onto the shaft tighten the bolts fully use nut link belting then no tensioning needed and bingo an alt drive !

 

[Gwil]

Another idea is attach a small rubber tyred wheel to the alternator and have friction drive on the prop with a spring that kept the tension.

I think you'd need a lot more tension than with a belt. Depending on the type of stern gear this could side load the stuffing box/shaft seal unacceptably.

When I made mine I turned up a pulley and added it between the gearbox flange and the prop shaft flange- only needs to be thinnish in the flange area so it doesn't significantly push the prop back.

If you use one of those specially wound Lucas 15amp ACRs they produce power at very low revs, ideal. Otherwise you need quite a big pulley on the shaft. Also worth putting the field through a rheostat to control charge and not stall the shaft.

 

[normspanners]

I think you'd need a lot more tension than with a belt. Depending on the type of stern gear this could side load the stuffing box/shaft seal unacceptably.

I understand your concern re stuffing gland but it would surely go closer to the Gearbox to keep it all out of the bilges

 

[Rig Pig]

certainly can.

He wants to run an alternator of the prop.

Ahh, I see a ships shaft generator! Just wondering why he wants to use the shaft instead of the engines belt drive?

 

[rikrobson]

Ahh, I see a ships shaft generator! Just wondering why he wants to use the shaft instead of the engines belt drive?

Surely you'd want power of the engine?You'll be making power in idle and have more revs available.
If you use the stern tube you'll only have power when the propeller is turning. I'm assuming in all this there is a reduction gearbox too.that mea s there will be relatively low revs compared to using the auxiliary belt on the motor

 

[hunter27]

[QUOTE=" Just wondering why he wants to use the shaft instead of the engines belt drive?[/QUOTE]

So it will power the alt when he is sailing but the engine isn't running, hope he has a big prop

 

[octo0072000]

other point what happens to the alternator when the props in reverse anyone does it upset the coils diodes etc

 

[rikrobson]

other point what happens to the alternator when the props in reverse anyone does it upset the coils diodes etc

The diodes will cope. Alternators are usually 3ph that is then rectified.

 

[knighty]

do props spin fast enough when sailing with the engine off to generate any real power ?


you can get little water turbine generator thingies that drop over the side of a boat?

 

[rikrobson]

Or a wee wind turbine.

 

[Rig Pig]

Or a generator!

 

[normspanners]

other point what happens to the alternator when the props in reverse anyone does it upset the coils diodes etc

The diodes will cope. Alternators are usually 3ph that is then rectified.

DIODES ?? it makes no difference still charges either way coz its ac and recified to dc so they have no coping to do al you need is a none directional fan!