How fast do you want to go?
The following formula is used to estimate potential top end.
The Square Root of (Total Shaft Horsepower / Weight ) x Hull Rating = Speed

Hulls are rated by their efficiency. The more efficient the higher the rating.
These Ratings have been developed from experience, and are as follows:

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    Hull Ratings Optimum Slip
Non-straked hulls

Direct shaft drive, No Strakes, Sportfish

200 13-15%
V-bottom w/liftfing strakes With strakes, Standard drive height 225 10-13%
Fast V-bottom High Drives, boxes, notched transom 250 8-9%
Ventilated V-bottom High Drives, notched transom 260 7-8%
Catamaran Pre mid 90's cats 275 6-7%
Fast Catamaran New Skaters, etc. 300 4-6%
Boat Speed Calculator ( Top End Speed )
Weight Total Shaft Horsepower Hull Rating Top End Speed
mph
Wet Weight Horsepower at the shaft. 200 - 300
Fill in Weight, Horsepower and Actual Speed to find your Hull's Rating.
Fill in Weight, Hull Rating and Actual Speed to find your Shaft Horsepower.
Fill in Horsepower, Hull Rating and Actual Speed to find your boats Weight.
Knots - MPH
5 Knots = 5.8 MPH
10 Knots = 11.5 MPH
15 Knots = 17.3 MPH
20 Knots = 23.0 MPH
25 Knots = 28.8 MPH
30 Knots = 34.6 MPH
35 Knots = 40.3 MPH
40 Knots = 46.1 MPH
45 Knots = 51.8 MPH
50 Knots = 57.6 MPH
55 Knots = 63.4 MPH
60 Knots = 69.1 MPH
65 Knots = 74.9 MPH
70 Knots = 80.6 MPH
75 Knots = 86.4 MPH
80 Knots = 92.2 MPH
85 Knots = 97.9 MPH
90 Knots = 103.7 MPH
95 Knots = 109.4 MPH
100 Knots = 115.2 MPH
105 Knots = 121.0 MPH
110 Knots = 126.7 MPH
115 Knots = 132.5 MPH
120 Knots = 138.2 MPH