Surgery required - The Nashers revenge

[Nasher]

Following last weeks dismal weather we've had a good few days mucking about in our spiritual home - Start Bay.

The Nashers Revenge, my 6.5M Ocean, has been going great with it's DT200EFI, and handled some interesting seas outside Dartmouth Harbour on a couple of days.

All was well until this evening.
Had a great run back across the bay, having seen seals off start point and a dolphin in Dartmouth Harbour right up by the lower ferry.
Recovered at the higher ferry slip to a huge smell of petrol, took out the bung from the transom to see what was in the bilge and had petrol absolutely pouring out.
Looks like the built-in stainless steel under deck 130l fuel tank has split.

Managed to siphon out @40l, which will keep the younger Nashers Bombard 380 and Suzi 9.9 going for quite a while, but when we get home I'll have to cut out the Jockey seats, followed by a huge hole in the deck and get the tank out to be repaired or replaced.
Followed of course by putting it all back together neatly.

When I stuck a wooden wind break pole down the fuel gauge hole to see how much was in it I could move a large piece of metal around in the bottom of the tank, so it looks like a baffle has come loose somehow, either tearing a weld and causing a hole or causing the leak another way.

Anyway, she's now laid up for the rest of the holiday, and you guys can expect a thread with pictures sometime over the coming months showing progress on changing it.

Nasher.

[mister p]

Shame.

[lakelandterrier]

Ouch!!!
That's a bugger, although I don't think the seas are to blame.
Well you'll have an interesting winter cutting out the old tank & installing a new one - that's a new and long post - pictures please.
Does this mean you'rre taking over the little Nashers' pride & joy for the rest of the week???

[whisper]

Mare

Can you not drain the fuel and run it on plastic tanks up on the deck for the rest of the season?

[Nick Hearne]

Originally Posted by whisper

Mare

Can you not drain the fuel and run it on plastic tanks up on the deck for the rest of the season?

+1 if you are down for any time I could lend you 2 X 25lt tanks and hose to keep you on the water, I'm in Salcombe till Sunday if it helps?

[Nos4r2]

Ouch!

[bedajim]

If you need some bits of stainless give me a shout

Jim

[Chris Caton]

sounds like a nightmare, good luck with the repairs if I lived closer I'd be happy to give you hand, but think its a bit too far even for me

[Cookee]

Stainless stress fractures - we always insisted on Aluminium for our race boat tanks......

[Trimix]

Wont Aluminium fracture ?

[Cookee]

Originally Posted by Trimix

Wont Aluminium fracture ?

In our experience S/S work hardens and fractures, if you put a soft base under an ally tank it will last much longer. Don't forget racing puts everything under much more stress than a leisure boat so my comments are based on real life experience. Bigger boats (semi displacement upwards) are ok that don't slam at all but smaller boat stress S/S tanks.

[Pete7]

Nasher, I know of a short round Welsh block who helped to take out a Pacific console and you know how that thread turned out

Tek Tanks in Alton could have some intersting solutions if you want to go away from metal tanks.

Pete

[Chris Caton]

Originally Posted by Cookee

Stainless stress fractures - we always insisted on Aluminium for our race boat tanks......

funny thing is I had it in the back of my mind someone had told me same thing, but I wasn't sure if I'd just dreamt it

[biffer]

Ali hardens along the weld , that's why you see fracture along the sides of an Ali weld, it's to do with the heat of welding it, baffles vibrate in both Ali and SS tanks, I can guarantee the you will find the baffle in the tank with little chunks of the tank wall attached to it. If they've only welded the baffle in in a few places that what happens, on a brighter note with only a few welds it won't be that damaged and an easy repair, taking to boat to bits is a different story

[Bigtalljv]

I spoke with an aluminum tank manufacturer the other day and she said they recommend strapping the tank in place instead of using mounting tabs. The tabs, she said, were where the tanks usually split.

[mister p]

For baffling, does anybody use foam blocking designed for the job instead of welded plate?The racing car and bike stuff.
Would work a treat.

[biffer]

To answer the last two posts in one go, tanks usually foamed in a rib, the mesh in racing car tanks is good stuff but if you get dodgy fuel you can't get it out, diesel bug, you might as well throw the tank away

[mister p]

Originally Posted by biffer

To answer the last two posts in one go, tanks usually foamed in a rib, the mesh in racing car tanks is good stuff but if you get dodgy fuel you can't get it out, diesel bug, you might as well throw the tank away

Buffer, the mesh you mention is invariably in foam blocks now. But I agree about contamination. Water being the main issue here as we're on about o/b's in this case.
The access to RIB tanks for removal of foam blocks through filler is easier than fast fill race tanks I believe, should tank need cleansing.

[Nasher]

Thanks guys.

The younger Nashers did let me borrow the Bombard a bit today, so had some fun anyway.

I did think about finding some seperate tanks, thanks for the offers of loans, but we're off home tomorrow anyway so it didn't put too much of a dent in the holiday.
I might however consider running the boat for a couple of months on them until I start the replacement project.

I'm sure it's going to be a great project, but do need to consider what I replace the tank with, or even if it's repairable.
I'm keen to look at my options, including Stainless, Ali, and Plastic, and look at the merits of each.

I'm even thinking of glassing in a long box with a reasonable size hatch and going for a bladder.

It's a shame I'll have to cut the jockeys out first rather than cut a bigger hole in the deck around them, but I know they sit directly over the longitudinal stringers, and the deck is bonded to the stringers.

Basic initial plan is to cut the deck along the inner edge of the stringers, as I know exactly where they are, replace/repair the tank then bond secondary smaller stringers inside the old ones to sit/bond the deck back on.

The deck has a pattern of anti-slip and flowcoat chevrons in it at the moment, so doing it as above I'll be able to reuse the bit of deck I cut out, then fill the join and flow coat some lines to add to the pattern.

Any discusion on the merits of different tank materials will be greatly appreciated, athough I think Cookee obviously knows what he's talking about and might get a call over the coming weeks.

Nasher.

[Chris]

Originally Posted by Nasher

I'm keen to look at my options, including Stainless, Ali, and Plastic, and look at the merits of each.

Don't forget GRP...

Hundreds of Osprey's swear by it