suzukidave
Petty Officer 1st Class
- Joined
- Jul 1, 2000
- Messages
- 387
need help picking where to jump next.
I have purchased a new boat and I seem to be underpropped and I'm looking for some suggestions as to where to go as it is looking like I'll have to make a leap of faith as I can't find a dealer nearby with a prop I can demo. I am going aluminum to s/s, and the prop chart shows I will dropping one inch in diameter and there are just too many variables for me to figure it out.
19' grady white tournament dual console, modified v. hull, 8' beam. 1985 120hp johnson. v6 gearcase. 15.5x15 oem prop. dry weight 2100 lbs empty without motor.
WOT range for motor 5000-6000
performance
-driver only 6000 max rpm, 35mph @ 5800 rpm, (gps measured), (34 mph at 5400)
-3 adults + 2 kids 6000 rpm max 34mph @ 5800 rpm (33 mph at 5400)
-2 adults + 5 kids -5900 rpm max 34mph @ 5800 rpm (33 mph at 5400)
comments
-i'm thinking my tach might be off a little and the motor is governed at just over 6000? power seems to drop off over 5900 rpm and it is no faster after 5800
-motor is in lowest hole on transom
-boat planes right away in all scenarios unless you put all 5 kids behind the helm and even then the bow goes up but it's quick to plane
the next propeller size recommended is 14.25 x 17 then 14.25 x19.
I want to go with a stainless steel prop. main use will be cruising in semi-sheltered salt water so chop but no rollers.
a local prop shop has recommended a 19p but it's a special order so no test drives. An online prop place has recommended a 21p but no return either. online is a much better price.
Ideally I'd like to try a 17 first, but if I think 400 rpm for a 1 inch diameter reduction and 200 rpm for stainless steel, then I am at 3 inches of pitch. the performance makes me think i am overpropped at least 200 rpm, so I get to 19 inches of pitch fast.
what do people think? suggestions for what prop to use also welcome.
I have purchased a new boat and I seem to be underpropped and I'm looking for some suggestions as to where to go as it is looking like I'll have to make a leap of faith as I can't find a dealer nearby with a prop I can demo. I am going aluminum to s/s, and the prop chart shows I will dropping one inch in diameter and there are just too many variables for me to figure it out.
19' grady white tournament dual console, modified v. hull, 8' beam. 1985 120hp johnson. v6 gearcase. 15.5x15 oem prop. dry weight 2100 lbs empty without motor.
WOT range for motor 5000-6000
performance
-driver only 6000 max rpm, 35mph @ 5800 rpm, (gps measured), (34 mph at 5400)
-3 adults + 2 kids 6000 rpm max 34mph @ 5800 rpm (33 mph at 5400)
-2 adults + 5 kids -5900 rpm max 34mph @ 5800 rpm (33 mph at 5400)
comments
-i'm thinking my tach might be off a little and the motor is governed at just over 6000? power seems to drop off over 5900 rpm and it is no faster after 5800
-motor is in lowest hole on transom
-boat planes right away in all scenarios unless you put all 5 kids behind the helm and even then the bow goes up but it's quick to plane
the next propeller size recommended is 14.25 x 17 then 14.25 x19.
I want to go with a stainless steel prop. main use will be cruising in semi-sheltered salt water so chop but no rollers.
a local prop shop has recommended a 19p but it's a special order so no test drives. An online prop place has recommended a 21p but no return either. online is a much better price.
Ideally I'd like to try a 17 first, but if I think 400 rpm for a 1 inch diameter reduction and 200 rpm for stainless steel, then I am at 3 inches of pitch. the performance makes me think i am overpropped at least 200 rpm, so I get to 19 inches of pitch fast.
what do people think? suggestions for what prop to use also welcome.