Originally Posted by Rokraider
Does the different hull shape at the stern where the Hamilton was, make much difference to handling now it has an outboard?
The boat is only missing less than 1 meter of Vee at the stern (about 10 cm), but yes,
the pivot point is more forward than the 7.4X I had as comparison.
Since the overall performance improved so much by the outboard (more than 30 percent on ALL performance) i feel that I am a bit comparing apples and eggs with regards to the shape of the hull vs performance.
Negotiating waves at all speeds is not really different than the 7.4x, nor do i notice any difference in 'landing' after being airborne in the conditions we use the boat in (mainly on the IJsselmeer, which is a bit like the solent but fresh and a bit shorter waves). In large waves + windspeed in excess of 25 knots the bow seems to be a bit lighter when going against wind/waves but this is also going 10 knots faster than in the old situation.
A friend of mine is a naval architect and after some 'quality pubtime' on the issues of changing the inboard to an outboard.
The boat is now about 250 kg lighter now and yes she sits a bit higher in the water but that is 2,5 cm tops at the bow and only a littlebit at the stern so definately the center of gravity moved backwards from the situation with the inboard/hamilton (actually more than we expected , a hamilton apparently is much heavier due the water in it which we didnt consider at first) .
The missing vee is about 7 dm3 additional volume, i.e. 7 liters additional buoyancy in static/sub planing conditions and this effect - we reckon - is much smaller than the movement of the center of gravity . Unfortunately my nautical architect friend hasn't had the time to make any CFD calculations ;-)
We decided (the cheap Dutch solution yes) to play it by ear for how it goes with a planing boat and experiment with the ballasting of the bow instead. If not satisfied by ballasting the bow in the middle of the season i think I will get out the rubber gloves, resin, glass etcetera again and start working on a box at the stern to continue the vee all the way back to the stern.