Please Help With my Hull And fitting trim tabs

LJ's right, I think.

With that hull configuration and weight, 80 hp is probably not enough to plane. A prop expert will help you get the most out of the rig, but I suspect there is just not enough power.

Consider that she had 200 hp before; now only 40% of original power.

 

Strap a turbo to it and get the prop right? Mind you unloading it and starting again is probably the most practical advice.

 

I can't argue with anything the other guys have said.

Did you say that your engine is revving to the 4500rpm max while trying to get over the hump? If it will hit 4500 and isn't planing, you need a little more pitch.

To answer your question about trim tabs...No problem. Cut cardboard templates to match the full width of those two tunnels. (one on each side of the hull) Take them to an aluminum fabricator. (I guess that would be an aluminium fabricator on your side of the ditch) Have him make you some big trim tabs(like 400mm long) curved to match your tunnels and with a degree or so of downward pitch.

If you can get over the hump, the boat should plane. 12 knots is knocking on the door of planing, If you can get 15, then you can get 20.(Probably)

20 kts on an 80hp inboard will probably be pretty econimical, too.

Having the prop pitch adjusted and a custom pair of trim tabs will cost a little, but it might be worth it to you to possibly save a project you have put so much time and money into.

Lance.

 

If you can't get that hull to plane it's underpowered or overloaded.

 

I would be looking at moving the fuel tank further forward.