The Difference between Crouchs calc. and Castle Marine is 4in of Pitch.(20 vrs 16) Both have 19 in Dia. Engine manf' typically rate their...
Forgot to mention; Make sure your motors are in tune and the Boat Bottom is clean (not fouled). Also the 16 in.Prop Dia is important - don't go...
Assuming your Engines are 350 cu in and 270 HP. Figuring 9500 lbs w. 270HP @ 4400 rpm Motors, 1.52 gear, Prop calculates to 16 x 15, 3 blade -...
You need to provide gearbox ratio , Also is 8000# with fuel, gear and normal passenger load? ----- Jango
I would consider changing rotation of one of the Engines. i.e. Camshaft, starter and alternator etc
No problem at all using the 72C,s. Probably the Best Transmissions out there! You just need to align the oil pump for the correct rotation - a 10...
71C,s have a 4" dia coupling and the 72C, a 5" dia.
If you're fairly confident in having 300HP, go to the 15 Pitch otherwize use the 13 Pitch. Bronze or S.S. props can be repitched to 14 P., but I...
I agree with jonr. With 8500# gross @ 4000 rpm Prop needs to be 16 x 14 Speed increases to 28 mph. Adding 1000# should Drop rpm,s to abt 3750...
16 x 13 Props @ 26 MPH Max. Cruise about 18 MPH @ 3000 rpm
Since many Builders look at this Design, as a "copy of the 40,s - 50,s Chris Crafts, where the Interior colors are a Dark Red.The natural thing to...
Mark, If 53HP is available at 2100 - 2200 RPM, The 14x13 should work fine, otherwise use the 14x11 with slightly less speed. Slip is the...
Mark, 2000# w. 53Hp @ 2400 RPM would require a 13x13, 3 bladed prop, 24mph w.17% slip 2000# w. 53Hp @ 4000 RPM, a 10x8, 3 bladed prop, also...
Just wanted to add: In addition to reducing Pitch to 11 or 12, you need to go to a 16 Dia to limit Slip and get max performance. I believe the...
4100 - 4200 RPM with 17 pitch is what I would expect, especially with 135 HP. Reduce the pitch by 6 in. ( to 11P.) and you should see a...
Using PropClac, "semi displacement hull" shows a 16 x 11, (15.75 x 11.15p ) @ 5000 engine rpm, providing 17.2 kts with 25% slip. This calculation...
Get Reel, Props are normally sized at MIN. load. If Max Load were used, motor could Over rev if full throttle were used during a Light load. I...
According to PropCalc, ideal Prop is a 19 X 14, 3 blade (55% DAR), which should provide a top speed of 24 Knts @ 4500 rpm @ 15% slip with a total...
I assume this unit is an 1/O not a pure inboard? Need to know Drive Ratio? Max speed with 340HP and 10000 lb (fuel and min passenger load) is abt...
With the 1.5 gear your prop will be turning about 500 RPM more, 3000 vrs 2486 @ 4500 motor speed. Assuming your present prop is correct, you will...