Drago Fiesta and Yamaha O/B, the finale

[clb1970]

Me again,
I thought I'd leave an update on the situation with the Drago and the Yamaha outboard. As you may remember, I was concerned as the engine wouldn't get past 42 to 4400 RPM with WOT and did about 12 knots consitently. After advice here, many discussions with friends, SWMBO and a marine engineer, I decided I couldn't afford a bigger engine just yet so tried a few other options.
A doel fin was fitted, this seemed to lift the back a little, but really didn't do much at all (it's for sale if anyone wants one!)
Then we looked at prop options. Running through various calculators suggested an 11x11 prop was suitable, unfortunately that's what I had, so had to fiddle some more. We tried a 10x10 which reved to 6k RPM at about 1/4 throttle and at 7 knots, we deemed this unsuitable.
A 12x8 was bought from Yamaha, which is giving us around 57-5800 RPM at WOT and a consistent 15 knots. I think this is the best we're going to get out of the little engine, so for now, I'm happy!

I wanted to thank everyone for their advice previously and I'm sure I'll have some more questions along the way.

Chris

 

[Kawasaki]

Yes I reckon thats about it.
I have been driving (Lawsey's of this Parish) a 560 Drago bit lately.
'Blue Moon' has a 90 4 stroke Yam at the blunt end

Which goes very nicely thank you.
But She needs it when fully loaded with peeps and dogs and stuff.

I reckon a 50 even on the 560 would struggle to make much more than 16 unless lightly loaded!

 

[Philiz]

Yes I reckon thats about it.
I have been driving (Lawsey's of this Parish) a 560 Drago bit lately.
'Blue Moon' has a 90 4 stroke Yam at the blunt end

Which goes very nicely thank you.
But She needs it when fully loaded with peeps and dogs and stuff.

I reckon a 50 even on the 560 would struggle to make much more than 16 unless lightly loaded!

Eh, you'll 'ave ter find summat else to do the pleasure trips with, he's back off hols next week