Repower 21

[Bushwacker]

Originally Posted by elpez

I repowered my 21 with the 200 etec in 2005, had some corrosion issues and BRP sent me a new lower unit, quiet, fast very nice, does not spin over 5,300 but that is the prop, gets up real fast. Would do it again.

You obviously have a 3.3L 90 degree big block version of the 200, since the small block 60 degree motor didn't come out til 2006, as a 2007 model. Sounds like it's a good match for the boat! Not sure about your 2005 model, but the OPTIMUM WOT rpm for the 2008 models was 5500-5600, so you're definitely overpropped if it only turns 5300. What prop are you currently running? Assuming your motor height is right and AV plate is dry when you're fully trimmed out on plane, I suspect you'd like the motor even more with a prop that has a little less pitch! You might check out the E-Tec Owners web site, http://www.etecownersgroup.com/post/...-Chart-2671224, and post current prop dimensions and performance info to see what they recommend for the best prop. The Rebel seems to be the favorite of the guys running heavy deep-V's for best fuel economy, good stern lift and ability hang on plane at low speed. Sort of like a 4-blade but without the drag of the extra blade.

Pair of Jacks, I notice the 200 HP small block OPTIMUM rpm is 5600- 5850, which confirms my suspicion that it's optimized for max HP rather than mid-range torque. If you're only turning a 14.5 X 15P to 5400 rpm with a light load, going up in diameter is probably the wrong direction unless that's a really lousy aluminum prop. Your 175 should be turning about 5600 with a light load. I would think the 15.75 x 15p Rebel would be even harder to turn. I can turn a 4B 15x15 PowerTech ELE series prop about 5400-5500 on my 20. but not sure that larger diameter Rebel would be any easier to turn, even with one less blade. Here's a link to the BRP props http://www.etecownersgroup.com/post/...-Chart-2671224. You might also contact PowerTech http://www.ptpropeller.com/content-c..._90_300hp.html to see what they recommend. They make some very nice USA-made props at very competitive prices. My prop is compatible with the Michigan 2-piece hub system which appears to be significantly more robust than the Merc Flo-Torq hubs I've looked at.

[Briguy]

I would buy the 200 hpdi. Bulletproof!

[McGillicuddy]

Originally Posted by pair of jacks

Ah, the dreaded prop- are you saying that going to the larger diameter prop will reduce rpms? The reason I was considering re-propping is that I've been told by a marina service mgr. and some others that the no-name prop is inferior to the BRP REbel and because of the design of the blades on the BRP that prop will "grip" better thus reducing slip and increasing power- they did not seem to believe that by going from 14 1/2 inch diameter to 15 3/4 would reduce rpm since I'm keeping the same 15 pitch. Now if you guys are telling my otherwise, then reducing rpms is something I'm not wanting to do obviously. Opinions??

All things being equal, a prop of greater diameter would be harder to turn because it has to displace more water. In turn you get lower rpms.

Being that you are talking about 2 different props of different shapes and maybe materials, it is possible that with less cupping and moderate rake a wider wheel could give you more rpm than what you currently get. There are SO many prop designs.

Svc mgr sounds like a salesman. In theory "better grip, reduces slip" if you have enough power. So it doesn't really increase power, but rather, requires more power as the prop is "holding" more water. "Power" is what you're about 400 rpms short on. If I'm not mistaken, your etec would be be happier if able to get 5800 rpms with your tyipical full load.

Pitch is in theory how far a prop moves in 1 rotation. The prop's cup, rake, & shape and the hull and its power work together to screw up the theory. The result is slip. So pitch is not necessarily interchangeable as svc. mgr suggested.

An 1-1/4" of diameter is significant. I would not drop 500 clams on the marina managers suggestion. Said Rebel might be the perfect prop but if he's so sure, ask him to loan you one.

In general, you need a stern lifting prop that is easy to turn. I don't know specifically the BRP products that offer that attribute, but Bushwacker or someone on the etec board might. PowerTech is making some fine props at very good prices. I would look at the MQS 3 blade ,the SCE and the ELE series. The MQS and SCE are proven stern-lifters. Maybe Bushwacker can offer more insight on the ELE series. Mercury's Mirage plus and Old OMC SSTs also have a strong following among SeaCraft owners on this board.

Looking at the Vipers performance on the Dusky, that might be worth learning more about. Keep in mind that such a performance does not necessarily translate to the SeaCraft hull.