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Old 20 April 2006, 12:37   #11
Country: UK - England
Town: Chesterfield
Boat name: Sea Quell
Make: Picton Cobra
Length: 5m +
Engine: Mercury 150 4 Stroke
MMSI: 235038298
Join Date: Sep 2003
Posts: 763
Originally Posted by Jonny Fuller
There's an echo here!
........... and another

I had exactly the same "problem" when I changed up to the opti and have put up with it for nearly a year until raising the engine 2 holes. It has transformed the boat - a much flatter wake and increase in revs.
I should have been braver earlier last year
I still have some rearwards spray (small) but think this is from the echo tranducer

Jeff is online now   Reply With Quote
Old 21 April 2006, 14:15   #12
Country: UK - England
Town: York
Boat name: Hi Flyer
Make: Humber - Ocean Pro
Length: 7m +
Engine: Suzuki 140hp
MMSI: 235033234
Join Date: Jun 2005
Posts: 89
Originally Posted by Jeff
I still have some rearwards spray (small) but think this is from the echo tranducer
Same here - since fitting my trandsucer I get a smaller rooster to one side of the engine. Bigger rooster when I forget the trim.

A different Jeff

Jeff Pike is offline   Reply With Quote
Old 21 April 2006, 15:26   #13
Country: UK - England
Town: Aylesbury/Lymington
Boat name: Farfetched
Make: Solent
Length: 6m +
Engine: 150hp Optimax
MMSI: 235021048
Join Date: Apr 2004
Posts: 858
"Trimming an engine in or down is moving the leg of the engine closer to the transom and will have the effect of lowering the bow of the boat. It will also get the boat on the plane quicker and make it handle better in sharp turns. You should start from standing with the engine trimmed in/down and also use this setting when heading into an oncoming chop as it forces the steepest part of the V of the hull to pierce the waves.

Trimming an engine out or up is moving the leg of the engine away from the transom and will have the effect of raising the bow of the boat. It will make the boat much harder to get on the plane and make the boat much lighter in turns and more likely to skip sideways. It does however when at speed lift a lot of the boat clear of the water resulting in far less drag. If the engine is trimmed out/up too much the prop will start to ventilate and you will have to trim back in or throttle down to get it to bite again. You trim out for maximum speed as the lower drag allows the boat to move faster. Also when in a following sea trimming out helps prevent the bow from stuffing into the back of the next wave.

Typically you will start from a standstill fully trimmed in/down then once the boat is up on the plane trim the engine out/up gradually - you will hear the engine rpm rise as the drag is reduced and therefore load on the engine decreased and the speed will pick up. This will continue as you trim out/up until there will be a change in the way the engine sounds, a rise in revs but a drop in speed - this is ventilation setting in and this point will represent the highest point you can trim out in the current conditions - so you trim back in/down slightly to get the prop biting again and this should be your top speed. Remember this point on the trim gauge and you can easily return to it later."

A masterful concise and clear summary.

And of course it has the benefit of reflecting my opinion 100%. thank you.

brucehawsker is offline   Reply With Quote

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