Prop Slip ? and Advice

[tahoejag]

Can anyone tell me the prop slip w given info? 411 - Am running 4800 (wot) at 43 mph (gps). Cruising speed is 2800 - 3000 rpm and falls off plane easily. Have sx smart tabs (#60) set at hole #4. Fuel economy could seem to be better. overall performance seems to be lacking....JMO. Not looking for hole shot rather stronger mid range and better top end. Considering 4 blade alum (solas amita) heard and read good stuff about prop. Want to stick w alum due to water conditions.

20.5 ft tahoe ski/fish (average load, 2-3 peop, 15 gal fuel, aprx #2800)
4.3l carb 190 hp
1.81 ratio
mich alum 3 blade 14 1/4 x 21p

 

[steelespike]

Re: Prop Slip ? and Advice

My figures say 18% slip, pretty high, all most into good pontoon numbers.
My first suspect Is the tabs too much pressure will make the boat lay down too flat.Too much hull in the water
plus the tabs them selves dragging in the water.Release the tabs completely make some test runs carefully checking the effects of up trim,.get us the results, wot rpm and speed lightly loaded.Then if tabs seem necessary carefully add with just barely enough pressure to be effective.
How old is the boat? You could be dragging around a load of water in the foam under the floor.Would make it slow to plane and fall off plane easily.
If you were at 10% slip your speed would be about 47.