Steven Cyr's Stella Blue Site

Stella Blue a Mainship 400 Trawler

Yanmar Test Data

The following data was published on the Mainship Website as data collected by the "major engine suppliers during real world boat tests of mainship yachts." This information is not any guarantee of any performance but is interesting to look at.

Keep in mind, these tests were done on a lightly loaded boat with brand new (read-very clean hull).

40 Trawler with Single Yanmar 6LYA-STP/370 HP

RPM	MPH	KNOTS	GPH Total	MPG/Statute	Range/Statute
1000	4.8	4.2	Not Measured	Not Measured	Not Measured
1500	7.7	6.7	3.1	2.5	670.6
2000	9.5	8.3	5.0	1.9	513.0
2500	10.9	9.5	8.5	1.3	346.2
3000	14.9	13.0	13.7	1.1	293.6
3500	19.2	16.7	19.5	1.0	265.8

Test date 4/26/05. Range based on 90% fuel capacity. Boat load included 150 gal gas, 130 gal water, 2 people with gear.

My personal experience and information supplied by several other owners indicates that the table above is fairly close but not completely accurate. Maybe some rounding or maybe there are other factors that they don't mention like wind and current.

In every report that I have received from owners of this engine in the same service, with a properly calibrated tach, is maximum RPM is 3425-3450. When you do the math, the above table would indicate propeller slip of 25%. That really is not probable with a heavy semi displacement hull like the 400. In my tests of Stella Blue, I find propeller slip to be about 39%, which is a more realistic number for this type of hull and load.

So take it all with a grain of salt, as you will probably never see the numbers in the lower sections of this table in practical usage.

Email - srcyr@sbcglobal.net