Keel Cooling again ;)

Hi all, a long time lurker and Steel 40 ft yacht owner here - ( She is a Ketch and weighs 12 Tonnes.) I would like some guidance from the forum if I may?

At the moment she is on the hard for an extensive refit over the next year or so. One of the jobs will be to repower her and I am looking to fit a Marinised 50 hp based on the Kubota V2203-B either a Nanni or Witchards. I want to run keel cooling as the boat is fitted with it but has never been used for coolant, it was used for Hydraulic oil, long story.
I have read all the threads on this and many other forums about keel cooling and I would like to run cooling for the new engine and also for the exhaust manifold cooling. According to Beta Marine for a V2203 requires the engine coolant to run over 12.5 sqr ft of steel hull presently the C channel fitted to the hull totals 9 sq ft. so the option is to add an extra 4 sq ft in the form of internal cooling tanks welded to the hull skin. However this still leaves the cooling required for the Exhaust manifold, as I will be running a dry exhaust I want to cool down the manifold and exhaust gasses to an acceptable level. The Boat will be sailed in the topics, Asia and the pacific mostly hence the water temp will be in the 25-30 deg range.

The plan (atm) is to run 2 x 9 ft runs of 1 inch Gal water pipe along the hull above the existing KC on both sides of the keel giving 13.5 sq ft of cooling surface area for the exhaust manifold? will this be sufficient for the manifold? the plan is to run a separate pump for this cooling?

Any advice would be appreciated

Cheers

Cal

 

Check this out: http://www.thebigsailboatproject.com/pro40.htm

This seemed to work for them, at least they had to use the bleeder valve