Deep in the bilge - what is it?

[Tintin]

Rooting around in the bilge, checking out where various wires ended up before I start stripping then out, I found this ...

View attachment 40333

I think it is a fuse to an earth bond to the keel bolts. It is in pretty bad shape.

I am loath to disturb its rest until I know what it is (because currently the electrics all work after a fashion), but I have sooo many questions.....


What type of fuse is it?

Any idea where I may get a replacement fuse and holder?

Is it necessary?

Should I leave well alone and hide it away again?

the boat is a Beneteau First 325

 

[macnorton]

It could be a galvanic isolator? have you got a 240v system on board?

 

[Tintin]

It could be a galvanic isolator? have you got a 240v system on board?

Hi MacN - there is 240v but it is too small to be a GI - it certainly looks like a fuse but not a type I am familiar with.

 

[Bilgediver]

Maybe a previous owner had SSB on board and this is the ground connection. Webbing like that is better than a normal wire for RF grounds.

 

[nigelmercier]

Does one end go to the mast? If so, lighting protection.

 

[Tintin]

Does one end go to the mast? If so, lighting protection.

Good point - will check - I have assumed it goes to a keel bolt

 

[sailorman]

Does one end go to the mast? If so, lighting protection.

Why fuse a lightning protection cable

 

[Bodach na mara]

Hi MacN - there is 240v but it is too small to be a GI - it certainly looks like a fuse but not a type I am familiar with.

Home-made galvanic isolator with undersized diode?

 

[nathanglasgow]

We have one of those too on our Dufour Arpege.The flat braided cable is connected to the forward keel bolt and then onwards to the fusible link and then to the mast.Always wondered what is was for.

 

[nathanglasgow]

Meant to say its connected to nothing else.So would appear to play no part in the rest of the boats electrics.Surveyour reckoned its for lighting protection

 

[nigelmercier]

Why fuse a lightning protection cable

So you have a known point of failure. It will be a BIG fuse, just under the rating for the wire braid.

 

[William_H]

I would not think you would fuse a lightning protection cable. Unless you thought that if the cable itself fused it would start a fire. In any case I think the voltage rating of the fuse would be exceeded and the fuse would continue to conduct with ionisation untill the cable evaporated.
I wonder if OP is sure it is a fuse and if so what sort of rating?
I would say just bolt the 2 cables together and delete the fuse. That is if it is for lightning protection. it might be a good idea to add more cable to connect more of the keel bolts.
OTOH if one bolt is vaporised you might not lose a keel or get too much water in. More bolts connected might mean more bolts vaporised. Who knows with lightning.
it did occur to me that if it was connected to the earth of aHF SSB aerial tuner then it may have been an isolation capacitor. But I gather it is connected mast to keel.
good luck olewill

 

[TradewindSailor]

How would a fuse work here? There is heavy strap joining both ends!

 

[VicS]

How would a fuse work here? There is heavy strap joining both ends!

????? heavy strap joining both ends?

A better photo of the item might help to identify it but perhaps lack of access prevents that.

 

[Tintin]

????? heavy strap joining both ends?

A better photo of the item might help to identify it but perhaps lack of access prevents that.

Yes, this was taken "blind" with my phone. Let me try a close up from the high res version.....

View attachment 40348

 

[TradewindSailor]

Sorry ... it looked to me like a short strap .... I didn't see the far side disappearing into the bottom moulding.

.... I'd be interested to know what it's for.