[PCW] re Domino was camera boat

[Georgs Kolesnikovs]

Bill wrote:

>My current project, 19m x 56,000#, yet to be launched,
>also has a pair of ~300hp engines.  I'm expecting 2
>mpg @ 10kn, 1 mpg @ 20kn.

I'm old fashioned and tend to think in GPH (gallons per hour) for 
fuel burn. Thus,

   2 miles per gallon at 10 knots = 5.00 gallons per hour
   1 miles per gallon at 20 knots = 20.0 gallons per hour

For ocean-crossing purposes, except in calm seas, I suspect you'll 
find the 10 knots much more appropriate.

I believe Wild Wind IV, a Tennant-Raedeke-Pachoud 60-footer, crossed 
the Pacific burning 5.17 GPH while averaging 9.3 knots. That works 
out to 1.8 MPG.

I don't have numbers at hand for a 60-to-70-foot monohull, but I do 
know a Nordhavn 47 just arrived in Gibraltar having burned 5.3 GPH, 
including genset and stabilzers, running at close to 7 knots across 
the Atlantic. An efficient displacement monohull in the 60-foot range 
running 9 knots like Wild Wind would probably burn closer to 10 GPH.

So, the passagemaking power cat may have a slight advantage in 
fuel/speed efficiency.

>To me the question is more than miles per gallon;
>there's a whole raft of reasons to go with multihulls
>and performance is an important one.

I'm familiar with the reasons and I applaud and love them. In fact, I 
own a power cat.

My point was that before ocean-crossing multihulls can attract buyers 
away from displacement trawler yachts, they will need to offer 
substantial improvement in speed and fuel burn. Which to me means 
boats like Globetrotter, not fat catamarans that perform only 
marginally better.

I hate to appear to be wearing a black hat but I'm getting weary of 
hearing how wonderfully efficient as passagemakers power catamarans 
are. On paper, sure, but they still have to prove it in the real 
world while crossing oceans. Which only a handful have done.

I wish you well, Bill, and look forward to hearing of your actual 
experience out there.

--Georgs
-- 
Georgs Kolesnikovs
   Power Catamaran World
   http://www.powercatamaranworld.com