View Single Post
Old 11-06-2016, 07:49 PM   #8
Peter Knowles
Member
 
Peter Knowles's Avatar
 
City: Victoria BC
Country: Canada
Vessel Name: Geordie
Vessel Model: 1953 38' Monk Tricabin
Join Date: Nov 2016
Posts: 12
Hi Mike,

Damn I hate vBulletin forum software, always seems to lose my typing.
Just rewrote this entire post!

You have a valid point and I admit I only mentioned the Beta 60 casually, Iím also considering the 90.
But I do believe the boat is overpowered.
At hull speed of 8 and change the engine is only at about 1/3 throttle and at what I like to think of as a wake based efficient speed of about 7 knots the big Perkins is only ticking over. Several sources estimate hull speed load at about 42hp.
Now having lots of experience at sea I understand there are times when reserve power is required, but I consider that emergency situations. And in those situations, roaring past recommended RPM is justified.

I also believe peak engine efficiency is at peak torque, in the case of the Beta 60, thatís 1700 RPM giving 42 HP, my magic number for hull speed. Less a little for mechanical loss takes me to my favorite wake based speed.

This also puts me squarely in the 70% loading that diesels love.

So on paper the 60 is perfect, the 90 only buys me some more oomph against headwinds.
Plus an extra $5K and a rather tight fit.

Welcome your, and everyone elseís thoughts.

I should say that I am resistant to knee jerk overpowering, I recently hauled a 24í Airstream all over North America with a 1962 Land Rover,........OK, it has a Chev V6 but still only about 160hp.
Some of the story here,...Travels With Geordie

Peter
Peter Knowles is offline   Reply With Quote