Saturday, August 1, 2009

What to do with a large empty keel?




Well, actually I have a number of options;

1. Have Bob build a full tank inside the keel using vinylester. He has done this before and it would offer the largest capacity. Downside include complexity (therefore cost) and no means of testing tank integrity before installation.

2. Build fiberglass supports inside the keel and install pre-made tanks of;
a. Rotationally molded, cross-linked polyethylene plastic or
b. Vinylester or
c. Aluminum (not foamed in and kept dry).

While I might loose some capacity with the second option it might prove safer as I can pressure test the tanks prior to installation.

PS. Should have stated that the tank will be for diesel.

4 comments:

rj said...

Wow. That must have been a tough job.

Our 28 foot sloop has a fiberglass fuel tank in the keel, atop the ballast, in a place very similar to this.

No foam, but it is shimmed on the bottom and sides with teak shim strips to keep it from moving around, also, the tank's top has glass tabs on the sides. They are fastened to two stringers that run along the side. 30 years old, never had problems.

Id say if this is an area that cant dry easily and quickly, avoid any metal tank.

Rotomolded HDPE would be nice if you can find a shape that will fit. Otherwise tooling costs would be outrageous. There is an outfit in Vancouver BC that will fabricate tanks by welding HDPE sheet stock.

I imagine you have seen http://www.ronco-plastics.com/

What will you use the tank for?

Nateetong said...

Hi, I am not far off that point now with my whitby 42. The previous owner said he had glassed in the top of the keel tank and fixed the problem. He has done so forward of the engine but not under the engine pan where I found holes in the top of the tank.

I am going to try to get the tank out now but wondered how closely you looked at the option of making the space into a fibreglass tank? I would love to hear any thoughts you had about this option and what would be involved in going that route. Were you only concerned about leaks on the top or somehow fuel migrating into other parts of the keel?

I have skilled fibreglass contractors available with reasonable labour costs and would love to keep bilge water out of that space! Once the tank is out I will ask some opinions from contractors but much point till they can see into the space.

By the way your blog is a great resource for me in the refit I am doing on my Whitby. I would like to do something similar but working each evening on the boat after work by the time I get home I don't have any energy left for this!

Cheers, Leon.

The Incredible Hull said...

Hi Leon

I nearly went the way of the glassed in tank but cost was a factor. The quote was +/- 6K$US. It just didn't make sense. If you can get the price below this then I would think that this would be the best option. Make sure your guy uses Vinylester and puts in the correct number of baffles and inspection plates. Slope the top of the tank back so that the actual bilge will be under the aft cabin and you should not have any problem.

Gerry

Nateetong said...

Thanks for the reply Gerry. Looks like blogger has had some issues as I could not post yesterday and the comments seem to have disappeared now.
I have all the fibreglass cut away from the top of tank now and will attempt to pull it out today. Now that I am this far into it I feel less daunted as there is not turning back now!
I will let you know which way I go but the fibreglass option seems to be the best long term solution if it can be done properly and for a reasonable price.
Cheers, Leon.