Technical bow thruster Q

Elessar

Elessar

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I have a sidepower SE80. Twin prop.

The barnacles between the props had significantly impacted performance and on my last lift and hold i didn't have time to remove a prop.

So dived down yesterday to remove a prop and clean it all up.

Each prop has an anode which covers the nyloc nut, and the anode it held on by an stainless bolt which screws down the centre of the shaft.

All cleaned up and on re assembly i couldn't get the allen bolt in. Took a while to realise the problem but in removing the anode i snapped the end of my leatherman pliers off in the thread, ie in the middle of the shaft.

So 2 questions:

Are the shafts electrically connected i.e. do i have to worry immediately about corrosion or will the other anode protect it?

How do I get the bit of pliers out?

Good news is the bowthruster now pulls the boat and pontoon sideways.
 
i would expect they are connected so the other anode may provide limited protection. I wouldn't expect they are attached to your bonding circuit.

How much do these anodes wear. If not much then I wouldn't worry too much.

Now about the tip of your pliers ...

Out of the water job. Possibly try to rotate the piece anti clockwise to unscrew it. If there is space either side grind a slot in a decent screwdriver blade = avoid heating the tip as you grind the slot as you need to preserve the strength without making it brittle. Or perhaps have a word with Roy and see if he can spot weld a thin rod to the end to see if it can then be yanked out - this would need a very accurate touch with the rod. Otherwise a spark eroder, but these are not a commonly found machine.
 
superheat6k said:
i would expect they are connected so the other anode may provide limited protection. I wouldn't expect they are attached to your bonding circuit.

How much do these anodes wear. If not much then I wouldn't worry too much.

Now about the tip of your pliers ...

Out of the water job. Possibly try to rotate the piece anti clockwise to unscrew it. If there is space either side grind a slot in a decent screwdriver blade = avoid heating the tip as you grind the slot as you need to preserve the strength without making it brittle. Or perhaps have a word with Roy and see if he can spot weld a thin rod to the end to see if it can then be yanked out - this would need a very accurate touch with the rod. Otherwise a spark eroder, but these are not a commonly found machine.
Click to expand...

Anodes are 10-20% spent after 18 months. No not connected to the general bonding, im sure of that as I installed the thruster.

The bolt is quite thin, m5 i guess. And the bit of pliers is recessed into the hole. The shaft itself is in a 185mm diameter tunnel, and when my hand is on it my arm disappears to the elbow. Getting machines in not easy therefore.

And the boat doesnt come out! An expensive mistake this i fear.
 
I wouldn't panic. Underwater the boats moving and you are moving too. Once ashore the broken tip will probably come out quite easily as very little is keeping it in. Re anodes the drive shaft will often be connected (although not well) through the gearbox to the other side. So not all protection is lost.
 
Elessar said:
Anodes are 10-20% spent after 18 months. No not connected to the general bonding, im sure of that as I installed the thruster.
Click to expand...

Mark, wont the anodes bond via the gbox and then the body of the motor all the way through the negative cable to the battery (ies) which are typically bonded to the engine blocks etc etc?
Or have you installed bow thruster batteries in the bow?

cheers

V.
 
vas said:
Mark, wont the anodes bond via the gbox and then the body of the motor all the way through the negative cable to the battery (ies) which are typically bonded to the engine blocks etc etc?
Or have you installed bow thruster batteries in the bow?

cheers

V.
Click to expand...

bow thruster battery in the bow. Windlass cables charge the battery, via a VSR.
 
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