Positioning of Bilge Bulkheads

[sveolo]

I am looking to replace the fuel tanks on my Union 37 (Full keel, 44 LOA 37 LOD, Heavy displacement sailing yacht). Unfortunately the current tanks are 2 terrible bladder tanks (probably installed on the cheap by previous owner). However to get proper stainless or plastic tanks in I am going to have to cut out and replace several of the dividing bulkheads in the bilge. Does anyone know how critical the exact spacing of these is likely to be? I would prefer to move one bulkhead forward by approximately 20 or 30 cm to allow for a single larger diesel tank? The current spacing of these bulkheads is quite uniform at about 100cm apart, by moving one forward a little, I will be able to have one larger tank. Any thoughts? Many thanks...

 

[oldharry]

You really need to get in touch with the designer for this sort of info. Most yacht designers are happy to advise on this sort of question.

 

[FullCircle]

sveolo
the reason it has bladder tanks probably was because of lack of access to get the tankage you need in that location.
What is your objection to well fitted bladder tanks? they should give years of good service and be easy to remove for servicing and cleaning.
If you do cut the boat about to get your tanks in, presumably you will have to seal them into place, making them difficult to get at for servicing or eventual replacement.

Like oldharry, I think you should contact the designer, or at least get a design house to survey the boat for potential design changes, as bulkheads usually are very structural in one way or another.

 

[pappaecho]

I replaced this year a flexible tank put into my Evasion 32 in 1978, and which only required replacement because one seam was starting to split on the top of the "tank"
When I put the new tank in, I did put some old carpet to provide a buffer netween the GRP and the flexible. I think you may add much cost for little advantage by going for either stainless or plastic rigid tanks

 

[sveolo]

Thanks for your thoughts...

After approx 20,000 miles with the bladders I am 110% committed to getting rid of them - reasons for replacing the bladders are:

1) Difficulty in knowing amount of fuel remaining in tank - despite trying all logical approaches...
2) Weaping fittings- despite numerouse attempts to fix
3) Difficult & slow filling due to need to carefully vent to ensure no air pockets
4) No balancing across tanks

Agree with all the comments above and just trying to work out best tank solution that doesn't involve bladders!

Many thanks.