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Old 01-24-2018, 11:50 AM   #9
smitty477
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City: Northport
Join Date: Aug 2015
Posts: 2,046
Quote:
Originally Posted by djmarchand View Post
For the Mainship you probably don't want to pull more than 150 hp out of each engine for best life. So according to boatdiesel's power calculator, 300 hp will push that boat to 17 kts. Gassers make about 12 hp per gph of fuel burned, so it will require 25 gph or about 0.7 NM/gal.

The Bayliner with the Hino diesels will do about 1/3 better, probably near 1 NM/gal at 17 kts. But pushing the Hinos to 150 hp each is too much, so I would keep it down to 14 kts or so.

Some Bayliners have been repowered with Cummins 6BTs, a much better engine IMO, and those could cruise at 17 ok.

David

The EH700 Hino's are higher cubic inch industrial engines that were typically utilized at 140+ hp for 24/7/365 operations in factory usage. I saw 8 of them rack mounted at a larger plating factory in Shimodate Japan when I was in tech service around the early 90's. It was the single reason I looked to find a boat that had these engines in them.
I bought our first Hino powered boat not too long after that - a 1986 38 Bayliner with the EH700's that were natural and rated at the 175 HP.
In our case we usually got right about 1.3 nmpg at 14-15 knots with a top capability at about 18 knots. As long as they are propped p reach the full 3,000+ rpms they can be run just about anywhere you like with a great service record. The same engines with turbos and intercoolers were in my 45 Bayliner rated at 220 hp - EH700TI.
The 38 Bayliner was also available with a 135HP Mitsubishi diesels as well as a pair of V8 gas engines - neither will be popular for longevity and fuel use if you cruise often above low hull speeds.
I moved to the Bayliner from an early (1986 as well) Silverton 34 with twin gas which was similar in may ways to the Mainship of its time. I found the fuel use at mid teens cruising to be just about 2:1 between the larger Bayliner with diesels vs the 34 Silverton with gas engines.
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