- Joined
- Mar 5, 2012
- Location
- floral city florida
I posted this here because I feel it's a Prop/Jackplate issue, and am hoping Jay or someone can tell me where to get started.
My problem: I have an 86 Shadow 20.8 ft tunnel V running an 86 200 HP looper. Jackplate is an 8 inch Bobs manual, and prop is a worked cupped 27 pitch X 13 & 1/4 inch 4 blade shooter.
Boat is porposing kind of slowly like crossing big waves but constant at midrange planing speeds around 30 through 40-45 mph. I can power through it on up to 50-60 mph at about 3/4 throttle, and further on to WOT as the rear of the hull lifts out of the water accellerating. I do not know top speed as this is a fresh rebuild during break in and only kept it at WOT for 5 seconds before backing off to 3/4 or 80 % throttle.
Boat is very trim sensitive to keep prop from catching air however water pressure is good at over 17 psi even at WOT. To me, though accurate measurements have not been taken yet (see photos) motor seems awful high when looking at it propshaft center to pad. This is my first tunnel V boat though so am not sure where is a good place to start. Holeshot is excellent (3 sec to plane bow down) as long as motor is trimmed all the way in. If trimmed out, planing is very difficult. to achieve as prop catches air and bow is so high you lose forward vision. Best speed is with motor slightly trimmed in just a little. Porposing occurs though no matter where trim is, especially in a turn right or left.
I'll gladly sacrifice a little speed to end this porposing at the midrange speeds if necessary. I know I could probably use a better prop. Should I lower the motor? Will that help with the porposing? Change prop to a higher diameter maybe with slightly less pitch? 5, or 4 blade, or over the hub design? Any recomendations would be helpful.
Thanks in advance for any help you can give. :wallbash:
My problem: I have an 86 Shadow 20.8 ft tunnel V running an 86 200 HP looper. Jackplate is an 8 inch Bobs manual, and prop is a worked cupped 27 pitch X 13 & 1/4 inch 4 blade shooter.
Boat is porposing kind of slowly like crossing big waves but constant at midrange planing speeds around 30 through 40-45 mph. I can power through it on up to 50-60 mph at about 3/4 throttle, and further on to WOT as the rear of the hull lifts out of the water accellerating. I do not know top speed as this is a fresh rebuild during break in and only kept it at WOT for 5 seconds before backing off to 3/4 or 80 % throttle.
Boat is very trim sensitive to keep prop from catching air however water pressure is good at over 17 psi even at WOT. To me, though accurate measurements have not been taken yet (see photos) motor seems awful high when looking at it propshaft center to pad. This is my first tunnel V boat though so am not sure where is a good place to start. Holeshot is excellent (3 sec to plane bow down) as long as motor is trimmed all the way in. If trimmed out, planing is very difficult. to achieve as prop catches air and bow is so high you lose forward vision. Best speed is with motor slightly trimmed in just a little. Porposing occurs though no matter where trim is, especially in a turn right or left.
I'll gladly sacrifice a little speed to end this porposing at the midrange speeds if necessary. I know I could probably use a better prop. Should I lower the motor? Will that help with the porposing? Change prop to a higher diameter maybe with slightly less pitch? 5, or 4 blade, or over the hub design? Any recomendations would be helpful.
Thanks in advance for any help you can give. :wallbash:
