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First trip out since fitting the doel fins on Saturday (to a Mariner 60hp 2 str bigfoot). Conditions rough chop
Here are what I remember of the claims on the box:
15 minutes to fit - yes this is true
Better top speed - Not yesterday, if anything about 1 knot down but I will be interested to try in calm conditions
Better fuel consumption between 20 and 50% better, average 30%. - Difficlut to tell but subjectively I don't think there was any difference mainly because I was having to run the same revs to get the same speed and I would assume that the only way it's going to save fuel is if I could get the same speed at lower revs
Smoother ride (less porpoising) - I think this is true but not dramatically so
'Power steering effect' - didn't notice one
Planing earlier - no noticeable effect but my boat and engine with just me on board and no doel fins, comes on to the plane about 10-12mph and about 3000rpm which is pretty good anyway I guess.
...... and here are a couple of other observations. It certainly feels nice when it's in the sweet spot but it is much more sensitive to trim changes - obvious when you think about the design. When you have got the trim wrong there seems to be a noticeable slowing of the boat and an increase in noise - perhaps the plastic doel fins are vibrating if their angle of attack is too large. I also felt a slightly alarming tendency to roll more when barreling along at 45 degrees to the waves.
I'll post another report when I've been out a couple more times.
By the way it was indeed possible to fit them while the boat was on the water - and I never dropped a nut or washer !
PS the other point to bear in mind is that they might foul your auxiliary - see other post
Here are what I remember of the claims on the box:
15 minutes to fit - yes this is true
Better top speed - Not yesterday, if anything about 1 knot down but I will be interested to try in calm conditions
Better fuel consumption between 20 and 50% better, average 30%. - Difficlut to tell but subjectively I don't think there was any difference mainly because I was having to run the same revs to get the same speed and I would assume that the only way it's going to save fuel is if I could get the same speed at lower revs
Smoother ride (less porpoising) - I think this is true but not dramatically so
'Power steering effect' - didn't notice one
Planing earlier - no noticeable effect but my boat and engine with just me on board and no doel fins, comes on to the plane about 10-12mph and about 3000rpm which is pretty good anyway I guess.
...... and here are a couple of other observations. It certainly feels nice when it's in the sweet spot but it is much more sensitive to trim changes - obvious when you think about the design. When you have got the trim wrong there seems to be a noticeable slowing of the boat and an increase in noise - perhaps the plastic doel fins are vibrating if their angle of attack is too large. I also felt a slightly alarming tendency to roll more when barreling along at 45 degrees to the waves.
I'll post another report when I've been out a couple more times.
By the way it was indeed possible to fit them while the boat was on the water - and I never dropped a nut or washer !
PS the other point to bear in mind is that they might foul your auxiliary - see other post