Tinkerer

I get 17 % with my boat at 77 mph. And I am thinking about adding stand off boxes this winter.

puder

well ladies i got my greedy little hands on some 5 blade herrings to try out

i think they might be a little to big though . BUT we'll see if they bite any better than the mirages. I'm thinking they should. FYI the difference in quality between them and a merc prop seeems to be night and day. The blades are super thin and sharp as hell.

Payton

You may want to try a Mirage+ they have more cup and bite a lot better than a Mirage. Or send your props out to have some cup added. One propr shop told me that is why Merc came out with the Mirage+, because all the shops were cupping the Mirage.

A Hydromotive will give you more transome lift. Some boats , like Fountains, like that others don't.
I'm seeing 400 rpm drop from a Mirage 25 to a Mirage+25 and 10% slip on a 34' Super Hawaii. That's a 32' running surface with a nothched transom and 9000lbs running.

puder

wel i tried a lefty 29p 5 blade herring. WAY better.
i picked up 1 mph BUT it was at a MUCH lower rpm. The wheel is too big the slip numbers came down some which is good.

63mph at 4300 rpms isn't too bad. I need to get it up into the 5300-5500rpm range though.

homan

puder what motor do you have, Today was a banner day for me I took off the grate on my thru hull water intake was running a 24p Bravo 1-4 blade at 5200 and for the first time got 70.4 on gps out of the old pig.

puder

ho, very nice!

my engine is basilcally a 525sc. Very similar setup I have a little more cam than the merc setup and my static compresison is a tad higher. She made 551hp at 5400.

homan

what model do you have it sounds like we're comparable in HP mine is a 88 28' excel I put an Imco 2" shortie on and was running slower than the stock unit took off that cover for the south bay strainer and I guess lost some drag, different direction was like a mph slower but who cares it's close enough for me I 'm going to try a 25 mirage plus then send my best one to houston prop, but like a moron I sold a mint 25 last year cause I couldn't spin it on the other scow.

US1 Fountain

iTrader: (1)

I just noted all my rpms/mph readings in 500 rpm increments this past weekend. I only had 7% slip at 5100rpm. Running 25" Hydros. Going to put 26" on for this weekend and see if I can squeeze out another 2-3 mph.

jhnrckr

Any decent motor is going to stop making torque and start building hp at 5252 rpm so I would expect more slippage past 5200 rpm. Does it follow logic to try and prop the boat a little larger to max out rpms at 5200 or would it make sense to go with a smaller prop and spin it up faster?

puder

homan so teh shorty lower made you loose speed?
removing the whack crauiser style through hullpickup gained speed???

my boat is a 1987 26' scarab excel I think its pretty much the same hull as the 28 excel but without a swim platform. FYI i measured it once and i got 27' so i call it a 27' (ya gotta squeeze in that extra foot!!!!)

shes running well with the lefty 29 5 blade. solid 63 at 4300 rpms. On ceth rpms come up to teh powwer band she shdoul crank. Hering is willing to trade me props to getoteh right rpm range.

I refiguerd my slip number and i am down to 20%