Bowthruster anode screw stuck

[stuartwineberg]

Sidepower, twin prop with dome anode on the boss of the prop. Prop shaft has female thread into which goes an allen bolt securing the anode. Had divers down during lockdown to replace. Boat now out of water and cant shift the allen bolt to the extent where I have snapped off the(plastic) handle of my allen key. Prop is some sort of composite and access is restricted due to the tunnel. My concerns are risking snapping a blade off the prop as you have to jam the prop against the tunnel as you try to unscrew the bolt to stop the prop turning. Also concerned that if I apply heat to the bolt I might melt the prop. Cant use impact tools as it would certainly damage the thruster leg. Any suggestions?

 

[captainboo]

Had similar with a friends boat in that it wouldn't move at all. Used a Dremel with a 'burr' type bit to grind a slot through the anode remains either side of the bolt head so the anode could be split in two using a screwdriver in the created slot. Once the anode was free the bolt came undone easily.

 

[VicS]

Sidepower, twin prop with dome anode on the boss of the prop. Prop shaft has female thread into which goes an allen bolt securing the anode. Had divers down during lockdown to replace. Boat now out of water and cant shift the allen bolt to the extent where I have snapped off the(plastic) handle of my allen key. Prop is some sort of composite and access is restricted due to the tunnel. My concerns are risking snapping a blade off the prop as you have to jam the prop against the tunnel as you try to unscrew the bolt to stop the prop turning. Also concerned that if I apply heat to the bolt I might melt the prop. Cant use impact tools as it would certainly damage the thruster leg. Any suggestions?

Allen key with a plastic handle ??

Can you not use a standard Allen key, or if access is difficult use a hex bit in a socket set with an appropriate extension ?

 

[stuartwineberg]

Allen key with a plastic handle ??

Can you not use a standard Allen key, or if access is difficult use a hex bit in a socket set with an appropriate extension ?

Yep - on the agenda but just scared of breaking something else especially the prop that has to be braced against the turning force

 

[Ammonite]

Allen key with a plastic handle ??

Can you not use a standard Allen key, or if access is difficult use a hex bit in a socket set with an appropriate extension ?

Loads have plastic handles. Either a T bar type or ones like this
https://i.ebayimg.com/images/i/191028084432-0-1/s-l1000.jpg
Im about to do this job on mine and would be worried about damaging the props if using a lot of leverage. You'll probably be ok with a small ratchet though. If that doesnt work i suspect grinding away / splitting the anode is the way to go. Even if it doesnt budge immediately at least you can then get some plus gas on it

 

[stuartwineberg]

Had similar with a friends boat in that it wouldn't move at all. Used a Dremel with a 'burr' type bit to grind a slot through the anode remains either side of the bolt head so the anode could be split in two using a screwdriver in the created slot. Once the anode was free the bolt came undone easily.

Interesting. The anode wastage on this side of the thruster is very slow so might just let it waste away until it can be removed. I suppose the alternative is to just have one anode on the side that undoes easily but I have concerns then about balance and vibration in the thruster

 

[stu9000]

I've had the same issue and will be attacking it with the dremmel next time she's out of the water.

 

[rotrax]

Following advice on here - very GOOD advice as it turned out, after removing the cap screws on my Sidethruster a vibrating multi tool was the answer to remove the stuck on remains of the anodes. I ran an M8 tap down the middle of the new ones. Next time the cap screws are removed, putting an M8 X 50mm bolt into my tapped holes MIGHT push them off. No doubt I shall find out.

The vibrating tool seemed to shake them loose. As for undoing them I used a 3/8 drive socket allan key on an extension and ratchet.

Plenty of Plus Gas and left for 2 nights was needed!

 

[stuartwineberg]

Following advice on here - very GOOD advice as it turned out, after removing the cap screws on my Sidethruster a vibrating multi tool was the answer to remove the stuck on remains of the anodes. I ran an M8 tap down the middle of the new ones. Next time the cap screws are removed, putting an M8 X 50mm bolt into my tapped holes MIGHT push them off. No doubt I shall find out.

The vibrating tool seemed to shake them loose. As for undoing them I used a 3/8 drive socket allan key on an extension and ratchet.

Plenty of Plus Gas and left for 2 nights was needed!

Bit of a misunderstanding here. I dont have a stuck anode. I have an anode retaining screw that wont come undone.

 

[Pasarell]

I had exactly the same problem with my anodes. Eventually wedged the props with a large screwdriver and put a clamp on the allen key to give about a 10 inch handle. The screws came out very easily once I broke the Loctite seal. No damage to the props or any other part of the thruster

 

[Ammonite]

How about using multiple wedges to lock the props in place so you are not putting all the pressure on one blade? Id be fairly confident this should work

 

[stuartwineberg]

How about using multiple wedges to lock the props in place so you are not putting all the pressure on one blade? Id be fairly confident this should work

Yep - makes sense - thanks

 

[LittleSister]

Having recently acquired a Sidepower thruster, I am wondering how I can avoid this seemingly common problem arising in the first place.

The manual says use Loctite on the anode retaining screw, but doesn't specify which type. Is excessively strong Loctite perhaps an issue? I seem to recall that it's a pink (or maybe it was red?) one (not the strongest) specified for the anode retaining screws on my feathering prop.

Any other ideas/suggestions?

I have been musing about the possibility of replacing the anode screw with a longer set screw, or piece of studding, and have the anode clamped by lock nuts. [Update: My MkII version of the concept is an allen key socket (forgotten correct name) headed screw, with a couple of hexagon nuts to lock/unlock the anode in place.] Locking and unlocking is done with a long allen key (to hold the screw) through a box spanner (to unlock and withdraw the nuts).]

 

[VicS]

Having recently acquired a Sidepower thruster, I am wondering how I can avoid this seemingly common problem arising in the first place.

The manual says use Loctite on the anode retaining screw, but doesn't specify which type. Is excessively strong Loctite perhaps an issue? I seem to recall that it's a pink (or maybe it was red?) one (not the strongest) specified for the anode retaining screws on my feathering prop.

Any other ideas/suggestions?

I have been musing about the possibility of replacing the anode screw with a longer set screw, or piece of studding, and have the anode clamped by lock nuts. [Update: My MkII version of the concept is an allen key socket (forgotten correct name) headed screw, with a couple of hexagon nuts to lock/unlock the anode in place.] Locking and unlocking is done with a long allen key (to hold the screw) through a box spanner (to unlock and withdraw the nuts).]

Dont use any of the red Loctite grades or you will need heat to release it

See:- Which Loctite to Use

 

[LittleSister]

Dont use any of the red Loctite grades or you will need heat to release it

See:- Which Loctite to Use

Ah, yes. My memory was confused - they call the low strength stuff 'purple', but it looks pink to me, and it comes in a red bottle! (Albeit with a purple/pink stripe.)

They say -
Purple - low strength
Blue and Green - medium strength
Red - high strength

The link you gave didn't work for me, but I found this page useful https://www.henkel-adhesives.com/mx...r-Blue-How-to-Choose-a-LOCTITE-Threadlocker-4