Gordon wrote:

How do I ballpark the fuel usage for a modified keel 37' ketch
18000#
at 5 knots with a Westerbeke 4-108 with a fairly clean bottom?

Had a fin keel that weighed around 8,500 and burned about 1.1 L/Hr at
hull speed

(18,000/8500)*(1.1 L/Hr) = 2.3-2.4 L/Hr

Add 10% for funzies.

Use 2.6 L/Hr for calculations till you prove it wrong.

Lew