Okay, I haven't had time to digest al lthis buit would I be right in thinking the following summary:
- You want a low RPM quiet engine for your daily commute with one aboard.
- You want it to do decent performance outside these times wth much extra weight aboard
- You have been doing a lot of maths to try & achieve this.
OK. I have a 1984 45m hull, transom only rated to 110Kg / 60Hp. Reason for this - it's made from 1/2" ply. The modern version of my hull is rated for something like 75 Hp / 150 Kg. - Why? - it;s 50% thicker, and the hull has a lot more reinforcing round the transom = much heavier. I have a Clamshell for a reason - it weighs 83Kg. My entire boat incl engine & full tanks clocks in about the same weight as the modern hull, and guess what - I can do 30 knots and drink 0.8l/NM just like the higher powered modern one.
if you want a quet 4 knot commute and a performance rib I think your best bet would be to buy a second boat with no transom (i.e a sweeping counter) and power it with either a small 4- stroke or an electric. Then re- tune your 60 to be the engine it was designed to be and put up with the noise when at full power, coz you are ging to need that power to plane.
Lift the hull out - you need buckets of power for that (do the lift - wing calcs or just have a quick look at hydrofoil boats & the size of the foils. Ignoring that, even if you do have this magic wing, a) will your vent plate be able to support the lift? and b) if you are lifting the hull out wil lthe engine's tilt bearing be able to support it?
I reckon lightening the boat and arranging the weight would be better use of your time, and If you can make this happen my suggestion would be to patent your findings before posting back with the results!