gregga

I'm going to try to get a hold of a good bracket with maybe 6" of setback and move the engine! Still having a merc guy check it out Saturday but we will start by engine positioning, also may take Johnny's advice and bolt it to the transom lol it is just a race boat!

rchevelle71

iTrader: (1)

What length shaft, 20" or 25"

JUPITER PULSARE

Gregg, the perfect amount of setback for your 21' V would be 12". You'll be far enough away from the transom to get clean water flow and have enough leverage to lift the hull free from the drag of the water. Spend the $$$ and get a good hyd. jackplate. I have a brand new manual 14" rapid jack andodized in purple available at my house if you need it. You should be able to spin a 24/26 pitch prop with a 200HP Merc.

TeamSaris

12 inches is WAY too much for this application, especially considering he will be racing it.

Too Stroked

x2!

Twin O/B Sonic

pm'ing greg, trying to help w/o having to debate the issues.

Do we know what the boat looks like? I do not. I didn't realize greg is going to race it. In the new single O/B class???

I built a hot rod JohnRude for a customer yrs back that had a very heavy splash of a 21' Superboat.
As I recall, we ended up w/16" on that boat and it ran really well w/it. Balanced very well. I set it up and tested props on it for the customer.
W/about 300 HP's I was GPSing 78 in that state of tune.
I ran that boat in chop but nothing close to "offshore".

Greg, I'm down in your area all the time and be glad to pop in and put eye balls on it for you if you like.

TeamSaris

Im pretty familiar with the hull, and spent a LOT of time with my boat (same bottom) with the same motor. I also know what it will take to make the boat run level in the ocean. Right now the big issue is the lack of a splashwell, which is why it has as much setback as it does. I think what hes going to do is a 6in hydraulic, that way he can go "up" instead of "out" for trailering. It will also help with the bungees, which it will need. Boat has a notch as well. 8 inches on my boat was great for the lake, 10 was flighty in anything more than a chop...couldnt tuck it in enough.
6 will be good for offshore.
Gregg, Gary knows his stuff, dont be afraid to take him up on that offer

Kurt Hamilton

I had a look on the hustler website and now have a visual on your boat. Still not sure what the weight is like. The 6 inch plate will be perfect for offshore. Don't let everyone tell you you HAVE to run prop shaft level with plank (it may well work out that is where it's quickest and handles best), I find running slightly deeper better for handling in the big stuff. There's no point having a 80mph boat in the glass water if you can't drive it fast in the rough. I would have said 1" under may have been a good start for overall handling and speed. Also there is no point having little gear case drag by running high if you can't trim the length of the boat out of the water (21' of boat will cause way more drag than the gear case).
I have a 21' revolution (ski race hull built in Australia) with a 300xs. I run a lot of big water and believe it or not I run 4" below plank! The higher I go it doesn't pick up that much speed but the steering gets heavier. I was running a 6" CMC hydraulic jack plate but It wasn't handling the pounding I gave it, and kept bending transom bolts. I recently made a static 10" setback (I only went 10" cause it was the only aluminium c section you can buy 1/2" thick) and used 3/4" bolts through transom and 8x 14mm bolts at engine bracket (2 in each corner). She doesn't budge now, my hull is on the heavy side so I didn't notice a huge difference going from 6-10".

Too Stroked

Didn't mean to imply that's where everyone needs to run. Mine's actually 3/4" below the pad and that happens to work out best for my hull / motor and average conditions on Lake Ontario. I had some fellow Progression owners from Long Island tell me the boat won't run for crap without at least 12" of set back. (I have 6" and it works just fine.) And as you've apparently already seen, lots of set back is tough on the plate and the transom. That's not a good combination in a race boat.

BTW, your whole post - as well as Johnny's - are spot on.

Twin O/B Sonic

Good points by FF and Kurt both.

FF, 10-4. Didn't catch that you had a similar hull. As Kurt says, going fast in glass means nothing in the rough. Also, based on the math Greg was giving me I was guessing it was a notched transom but wasn't sure.
There is a Checkmate dealer down here that is getting 90 out of some of his 22' and up single O/B's w/stock power and he is doing it with 18" + set back. I do understand thought that the farther you move that motor out on a stick, the sooner it (the transom) comes down off the next wave though.

As to motor height, testing is the only thing that will tell you that. On my old Sonic we tested that. We raised the motors 1/2" at a time until the speedo stop climbing and the tach continued, meaning past the optimum and into increases propeller slip.
Doing the same thing w/the current boat. Interestingly, both boats accomplished this w/o nose cones that many are trying to sell.
I got to about 8% on the old boat based on my readings. Greg is claiming 6% as is which is exceptional if accurate.

Carry on.....