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Old 07-24-2011, 09:04 AM   #19
Nomad Willy
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City: Concrete Washington State
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 18,738
RE: Fuel Economy Question

DavidM,

Good interesting post. But as to efficiency a long stroke engine has a heat sink advantage. The area of the cylinder and combustion chamber per cubic displacement is noticeably less so less heat is lost in this way. Heat loss in a heat engine is lost efficiency but there are other elements of the efficiency issue that may or probably swing toward the short stroke engine. So I think your implication is probably correct. Air cooling could conceivably swing it the other way. But variation in engine efficiency is small potatoes compared to variations in hull design. Good economy will not be achieved without a full disp hull in any boat that could be called a trawler. By the way how can a supercharged DD be referred to as a "naturally aspirated" engine. Won't even run without scavenging assistance.
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