mthieme
Captain
- Joined
- Oct 6, 2007
- Messages
- 3,270
Well, As long as I'm laid up for at least the weekend and bored already...I pulled my OMC manual out last week for a couple questions. I've been thumbing through it and discovering some unchartered territory. One little interesting section is a propeller chart I thought I'd share. This information should be generic enough to apply to most boats - gear ratio might be a factor though. Personally, I think the speed ratings are on the high side.
All 3 -blade prop recommendations...
4 cylinder with gear ratio of 2:1 and 1.71:1...
19-22' runabout/cruiser 13 3/4 x 15P 24-32 mph
17-20' runabout 13 3/4 x 17P 30-40 mph
16-19' runabout 13 x 19P 34-42 mph
15-18' light runabout 12 3/4 x 21 38-46 mph
15-17' hi perf. 12 3/4 x 23 45-52 mph
4.3 with gear ratio of 1.68:1
non-planing heavy 15 1/2 x 13P
22-28' cruiser 15 1/2 x 14P
22-26' runabout 15 1/2 x 15P 22-32mph
18-24' runabout 15 x 17P 30-39mph
17-20' runabout 14 1/2 x 19P 36-44mph
16-19' runabout 14 1/4 x 21P 40-49mph
15-20' hi performance 14 1/4 x 23P 45-56mph
5.0 with 1.59:1 gear ratio
non-planing heavy 15 1/2 x 13
24-28 heavy cruiser 15 x 14P or 15P
20-27' cruiser/runabout 15 x 17P
17-22' runabout 14 1/2 x 19P 39-50mph
16-20' runabout 14 1/4 x 21P 44-57mph
15-20' hi performance 14 1/4 x 23P 48-62mph
5.7 with gear ratio of 1.41
non-planing heavy 15 1/2 x 13P
22-28' heavy cruiser 15 1/2 x 15P
19-26' cruiser/runabout 15 x 16P or 17P
18-24' runabout 14 1/2 x 19P 40-52mph
17-22' runabout 14 1/4 x 21P 46-60mph
16-19' runabout 14 1/4 x 21P 40-49mph
15-20' hi performance 14 1/4 x 23P 45-56mph
All 3 -blade prop recommendations...
4 cylinder with gear ratio of 2:1 and 1.71:1...
19-22' runabout/cruiser 13 3/4 x 15P 24-32 mph
17-20' runabout 13 3/4 x 17P 30-40 mph
16-19' runabout 13 x 19P 34-42 mph
15-18' light runabout 12 3/4 x 21 38-46 mph
15-17' hi perf. 12 3/4 x 23 45-52 mph
4.3 with gear ratio of 1.68:1
non-planing heavy 15 1/2 x 13P
22-28' cruiser 15 1/2 x 14P
22-26' runabout 15 1/2 x 15P 22-32mph
18-24' runabout 15 x 17P 30-39mph
17-20' runabout 14 1/2 x 19P 36-44mph
16-19' runabout 14 1/4 x 21P 40-49mph
15-20' hi performance 14 1/4 x 23P 45-56mph
5.0 with 1.59:1 gear ratio
non-planing heavy 15 1/2 x 13
24-28 heavy cruiser 15 x 14P or 15P
20-27' cruiser/runabout 15 x 17P
17-22' runabout 14 1/2 x 19P 39-50mph
16-20' runabout 14 1/4 x 21P 44-57mph
15-20' hi performance 14 1/4 x 23P 48-62mph
5.7 with gear ratio of 1.41
non-planing heavy 15 1/2 x 13P
22-28' heavy cruiser 15 1/2 x 15P
19-26' cruiser/runabout 15 x 16P or 17P
18-24' runabout 14 1/2 x 19P 40-52mph
17-22' runabout 14 1/4 x 21P 46-60mph
16-19' runabout 14 1/4 x 21P 40-49mph
15-20' hi performance 14 1/4 x 23P 45-56mph
Remember outboards are usually geared lower then I/O's (normally around the 2:00X1 reduction) because they are high revving, low torque 2cycle motors.