what pitch???!

[oxo]

Hi,
Does anyone know what's the best prop and pitch to use on an xr2 with the best top end performance? its gonna be mounted on a marshan19. Xr2 is standard on a long leg if that makes a difference. any input much appreciated!

[Burty]

gearbox ratio?
height?

[Cyco]

Burty 26" chopper wasn't it for 79mph on your Marshan??

Got to be brave for that tho!!

[oxo]

To be honest, all I can see is that its a standard r/h gearbox. sitting on a standard leg, sitting on a standard marshan transom, leg being the twin exhaust port type. Just bought a 14x 27" cleaver about a week ago but after reading up a bit, realise this prop only seems good for a cat or similar!

[oxo]

Thanks cyco, chopper seems the way to go, can get my hands on a 14.5x28 chopper, but don't know if its gonna tear a standard box to bits!

[Burty]

don't run a chopper dude unless you really know what you doing as a marshan hull is too narrow and a chopper will throw you out!!
you want a nice 20 or 22" small hub laser 2 to start with.
i had to run a setback bracket on mine as couldn't gt the bow out of the water when engine was bolted on the back.

make sure you mount the motor in the middle

you can work out the gearbox ratio if you take the prop off and mark the shaft and case then turn the flywheel around twice, if the propshaft does one complete turn its a 2:1 box if it does more that one turn its probably a 1.87:1 box (which is more likely)

[oxo]

thanks Burty,
need as much advice as i can get!

[wiggy808]

Hi OXO I'm running a 26" tempest on my Marshan 19 at the moment. That's on a Mariner 200. It goes quite well with that on and manages 67. Not sure about the rev limiter on yours though, probably revs higher than my Donkey. I'm going to borrow a 28" chopper to see if I can make her a bit more lively

Burty, how far back did you set yours, as I'm having the same trouble. Trim has little effect on the boat. The centre of the bullet is 2" lower than the hull. Any advice welcome.

[Burty]

my fuel tank was in the bow when i bought it so i moved it to the back and fitted a CMC manual lifter which is 5 1/2" setback made it a much better boat and it went really well, shame the floor kept falling out!! i had an old merc 2.4 200 on mine and it ran 73mph @6800rpm with a worked 22" laser 2 no problem with the gearcase about 2" below as i didnt have low water pickups, i ran it once with a 26" chopper on and did 77mph @6400rpm but scared myself because everytime you lited off the throttle it tried to throw you out!!!! so when you wanted to slow down you had to ease off very very slowly so no good when the sea was a little choppy.

I'd have thought with an xr2 though you'll need a lower pitch prop as to make the power you need to be revving to around 7000rpm

[scottyboy]

Marshan 19, XR2 20" mid section, No set back, g.box bullet inline with bottom (2:1 cle), Used to rev mine at about 6800-6900rpm, 25" pitch modded over hub cleaver (was worked so much it wasnt really much of a cleaver in the end)(prob better off with a tempest or summin similar). Fuel tank and trim pump on transom. Bow tank is a definate in one of these. It will transform the boat! Think mine used to run about 73 on a good flat day but the marshan's havent got much beam so they will always be quick in a straight line and more of a handful in rougher sea's! I know coz i turned mine over! Bought a phantom after that!

[little rascal]

Originally Posted by oxo

thanks Burty,
need as much advice as i can get!

I have a Marshan 18 and it liked small blade chopper 14.25 x 28p when i had a Merc 1750 and raced in offshore 3C (2litre) 1: 1.87 62knots@6200 (i think it was..

http://www.youtube.com/watch?v=C4wKk5EisBg

http://www.youtube.com/watch?v=EuGdsbkx_UA