MILD THUNDER

iTrader: (3)

I have no experience with the any of these setups in this discussion. However, I have done quite a bit of prop testing on my boat, and another buddys boat with high propshaft heights.

A buddy has an older 38 Cig, with IVs on boxes. He had huge 5 blade cleavers. Boat took about 5000RPM to plane. Major blowing out and took a while to hook up. Next set of props was some 4 blade cleavers. Wouldn't plane at all. Just burned holes. Finally, a third set of props were tried. also 4 blade. Boat planes at 2900RPM. No slipping, no burnouts, and boat is faster with these than the original 5 blades. Hands down this particular set of 4 blades worked the best. Now, these were all mercury #6 style props. All the same rake. Slight difference in diameter, but most important, the cupping. is what makes them bite. We sunk the drives deeper with spacers, but really that wasn't the problem.

My 38 Fountain. First set of props were 18x27 3 blade cleavers. About 3500RPM to plane, overall not bad. Second set of 17x28 4 blades, no worky, no plane at all. Tried another set of 17x29 four blades, took 4500rpm and a long time to plane. Then, got my hands on a set of 16.75x27 four blades, layed over at 2800RPM, no slipping, planed like it had drives a foot deep in the water.

I guess what I am getting at, from my experiances, theres more to planing issues other than drive depth, and sometimes adding blades may not be the simple answer. As far as these 700/NXT/#6 boats go, I know they run good, but if you boat in rougher water, I'd be looking into making friends with the #6 drive rebuilders. They can eat #6's up.

HyFive578

iTrader: (3)

I don't really have any seat time with her yet. Just on the sea trial and she came right out; pretty fast if you ask me for such a heavy boat. My 38 took longer.. The Fountain "birth certificate" shows the drives never being trimmed up above 2, which surprised me but I guess in the 47 with the ITS transoms, that's all she needs.

mcprodesign

The problem is the 42 or 38 w 6 blades and a high x seems to have the blade fighting to get to the surface and spinning a tons Rpms. For mine it was 5000 - 5500 prms to get on plane. That vibration at high rpm makes the props fall apart from what I have gathered. I went to a 5 blade herring and now it is 4000- 4500-- rpms.. Same pitch and same hering style prop. I only use this prop for all out top end. I have maximus 5 blade of the same pitch 2800- 3000 rpms planing off. ( even with full fuel, 3 guys and 5 chicks and full coolers.) So that is my every day prop. About 3 mph short up on top but less rpms cruising. I think if you hold the Rpms under 3500 planning off the herrings should be better than say a 38 or 42 that has to turn 4500- 5500 rpms to get on plane

MILD THUNDER

iTrader: (3)

Sometimes adding blades doesn't necessarily mean better planing or cruise.

HyFive578

iTrader: (3)

Thanks.. that's helpful. My boat came with the 6-blade herings from the factory and as far as I can tell, the boat still has the original props. From what I recall on the sea trial, she planed off around 3300 - 3500. I will keep an eye out in the spring..