John - Thanks for this detailed information. Regards, Rob On Wed, May 20, 2020 at 3:33 PM John Schinnerer via montgomery_boats < montgomery_boats@mailman.xmission.com> wrote:
Last year I did some practical real-world tests of my Honda 2.3 hp long shaft on my 1974 M17. This was at Fern Ridge reservoir near Eugene, OR, where conditions ranged from completely glassy to whitecaps and gusts 20+.
My conclusion was that as an auxiliary, the 2.3 is enough motor for an M17. Including with a furling jib (which I have) - a bit more windage forward than hank-on.
In light air to glassy conditions, my results were:
At the minimum throttle to fully engage the clutch, I was cruising at ~3 knots.
At about 1/3 throttle - roughly where the 'start' position (little rabbit symbol) is on the throttle - I was cruising at ~4 knots.
Next morning in completely glassy conditions I repeated the tests - same results as above.
Then I went up to half throttle, which got me up to 4.7-4.8 knots. NOTE we are getting up to 3/4 or maybe 4/5 of hull speed here...
More throttle had, as expected when getting close to hull speed, rapidly diminishing returns, adding at most .2 knots as I put it up to ~3/4 throttle.
The motor being new and not even close to broken in per Honda's recommendations, I didn't want to run it any higher at that point.
Third day was quite windy all day until late afternoon. 15-20+ with gusts probably to 25.
I motored out and tried the same throttle settings direct into the heavy wind and chop, and also at quartering angles.
On average I lost only .5-.6 knot of speed from the strong headwinds. So for example the 1/3 throttle that gave 4 knots in calm/glassy gave ~3.5 knots into the wind. Half throttle would give ~4.1-4.2 knots instead of 4.7-4.8. The strongest gusts would briefly take that down another .1 knot.
I then sailed for a while, with reefed main and as much jib rolled out as I felt comfortable with. Did consistently 4-5 knots, maxed out at 5.6 knots at some point.
I had expected more of a hit on speed into the wind actually, with the "small" motor. So I'm pretty happy, at 31 lbs and high simplicity and what seems like great fuel economy, with a Honda 2.3 on my M17.
cheers, John
-- John Schinnerer - M.A., Whole Systems Design -------------------------------------------- - Eco-Living - Whole Systems Design Services People - Place - Learning - Integration john@eco-living.net - 510.982.1334 http://eco-living.net http://sociocracyconsulting.com