Newby with newly built cruiser Pic

So, this a 22' flying bridge cruiser, epoxy glass composite trimed out with magogany, berths for 2 in cuddy, walk in crapper, and powered by 5.7 L V8 and Volvo Duoprop. This my first substantial boat and only its first year of commissioning. I get about 45 MPH (or so says the speedo) and then some slow porposing starts with still an inch of throttle travel to go. So, I'm fooling with wedges on her bottom trailing edge which I hope will buck her up and let me use more throttle. I know I can do this with trim tabs but the boat is already so complicated I'd like to stay away from another system. Comments?

 

Here's another shot. Bow shot however dramatic does not tell you much about the boat.

 

Here's an old commercial fisherman's trick that might help you guess how much of a wedge you need. I haven't seen anyone do this on a boat going over 45mph, but they would tie a line under the boat from stern cleat to stern cleat (very tightly) and it would act like a wedge of about the same thickness of the diameter of the line. Your problem might alleviated somewhat by experimenting with moving some weight forward or back in small increments while doing trial runs; that is if you have any weights you can move around. Another approach you could take is being satisfied with a slightly less than 45 mph cruising speed which is not bad and it might turn out to be more efficient than using the last inch of throttle.
I don't know if you can adjust your lower unit angle in a bit but if you can that might suffice also.
Just some comments. I don't pretend to be an expert on this. But I've seen positive results with these techniques.

Gilbert

 

Hey thats a great idea Gilbert- much easier than glueing/tacking a series of different sized wedges into my epoxy bottom. we shall see.

 

Looks like it needs trim tabs.

 

It could also be a weight distribution problem. Try sequentially trimming the boat with water in portable cannisters and record the results. If successful, look at what you might be able to rearrange internally to shift the centre of gravity, or where to add a bit of ballast.