Thread: Design
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Old 02-03-2008, 04:04 PM   #6
Nomad Willy
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City: Concrete Washington State
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 18,743
RE: Design

Jay N,
I totally agree. I hope my Willard keeps the same record. I usually don't care if we go off subject but this time I do. I want to get to the bottom of this single twin efficency question. The thread is called Design so your'e not guilty at all but I'm having an awful time getting this question answered. At least FF has bellied up to the bar and made a claim. "But in terms of lowest fuel flow the single will be most efficent" Well now it may or may not be fact and it dosen't even need to be as long as you can convince me it is. I'll deal with reality when and if it comes in the near or distant future. Yes. With a given draft twins will have the advantage of larger propeller and I think the twin has it again with less turbulent inflow. I'm going to go out on a limb and say the twin also has advantage of larger disc area with a given draft. I still don't agree with FF or Marin about maintanance being double for a twin. Each engine will be half the size of the single so one would need filters half the size of a single, belts half the size, oil half as much ect but propeller maint will be much higher. I think maint costs for the twin should be about 120% of the single. Vinny, off the top of my head I think the offset propeller would reduce the prop walk going ahead too. How about putting the keel off center too ( a bit ) and ballance the whole thing out. I'm almost positive I hav'nt seen that done.
Eric Henning
30 Willard
Thorne Bay AK
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