Onboard petrol tank

[apeproductions]

Hi All,

I have bought an osprey 6.5meter rib built in 1998

It has an onboard petrol tank under the consul jockey seat. This tank has been decommissioned and external tanks have been placed in the back just in front of the transom.

Looking into the decommissioned tank, through the sender hole, it looks like the tank goes down through another hole below the floor level. It looks like this was done during manufacture as it is all well glassed.

I spoke to osprey and they suggested it might have been decommissioned due to the resin used when it was built is now dissolved by current additives to petrol.

Basically I am wanting to either reinstate it as a fuel tank or cut it out to make storage space under the seat.

Cutting it out is tricky as the tank is fibreglass and glassed in place, it is under the consul jockey seat which is glassed in place, so working in a very confined space and access to the tank.

Any thoughts on this are welcome.

Many thanks

Ian

[Pete7]

Ian, which model of Osprey are we talking about?

Also are you sure its a GRP tank. For many years Osprey used stainless tanks but wrapped in GRP to glass them into the boat, through the deck and sitting on a plywood base glassed to the bottom of the hull. Quite a good design and whilst GRP won't stick to S/S, it did hold the tank firmly in place.

Pete

[apeproductions]

Hi Pete, thanks for your quick response.
I'm now at the boat.
It does look like it is exactly as you have stated, aluminium tank glassed in, which goes below the deck and into the hull.
Just need to test it now for leaking.

Not sure if you'll be able to make it out from the attached picture through the sender hole, the tank seems to have two internal levels with a rectangular hole going to the bottom level in the hull.

[trevbouy]

I don't think this will work in your case but I've used Por fuel tank sealer before.

[Pete7]

Ian, that's not something I have seen before on an Osprey, what model is it?

I have a 33 year old diesel tank that is cleaner than that

Actually, I think you have a GRP tank.

It might be salvageable but you are going to need better access to the top as a minimum. Having dropped a torch into a stainless steel tank on a Viper 595 rib which then broke and the AA batteries rolled out, I cut a big hole in the top of the tank to remove the bits. Then used one of these to seal the hole back up. Worked well but needed a box of 6mm drills and an angle grinder to cut the hole in a stainless tank.

https://www.vetusdirect.com/fuel-tan...nk25-ftank390/

However, you must make the tank safe before drilling or going anywhere near it with an angle grinder. I can't advise on this, but I put boiling hot water in the tank with washing liquid splashed it around for an hour then put the garden house in the tank for hours to remove fumes etc.

Before you start, pressure test it. Can you beg or borrow a radiator pressure test kit?

Pete

[apeproductions]

Thanks Pete, for your help on this.

The tank hasn't been used for years so there should be no fumes.

I'm going to do some testing of it in the next week or so. Filling with water or old fuel to see if it is leakproof, if it is I'll do my best at cleaning it out, which might require cutting a hole.

In the meantime I've book one of these to have a look into it

https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1

I'll keep you informed as to how I get on.

The manufacturers plate doesn't give a model build date of 1996.

Cheers
Ian

[Pete7]

That's a good idea to see inside

I would suggest water rather than any sort of fuel to fill the tank.

Post a piccy of the rib and we will tell you which model you have.

Pete

[apeproductions]

see a couple of pics.