optimum prop 270 f.v

[alex]

Hi everybody,

Any ideas for the optimum dimension of propeller for my 270 fiesta vee (2002) 350 mag bravo 3, in order to get on plane the easiest/soonest possible?

I am facing difficulties to get on plane. If I do not use the flaps, someone  should go inside the fore cabin and stay there until the boat is on plane and of course I have to use all power of the engine (At this point the rpm goes only to abt 4300rpm.Is this normal?).
This situation is only with  ONLY 2 persons onboard!!!


 In case I have full water tank and full fuel tank, I am afraid that the boat will not get on plane without the flaps, and of course I do not want to be depended from  any flaps malfunction.

In view to the above I am considering to use a smaller propeller, so that to overcome this issue.

Is this a good idea? Any disadvantage for doing that? What i have discribed is normal and has to do with the prop dimensions or i have to check engine's malfuction.

Please note that the boat is equipped with a 5kw gen(additional weight)

Any reply will be highly appreciated.

Thanks

Alex.

[DaleM]

Alex I originally had a 24" propset on my 2000 FV 270 350 mag mpi B3, genny and a/c.  That wasn't too bad for me with a light load, 2 people 1 dog, 1/2 tank of fuel, 1/2 tank of water.  However when I loaded her up, 5 adults, 2 kids and same dog, we had to move around a little bit to get on plane.  I found a decent used 22"propset and it's a whole new boat.  Planes very quickly with 2 aboard and a full fuel tank.  Very happy with the change.  Will keep the 22" props on her and use the 24" as spares.  With the 22" I'm running 42 mph speedo at 5000 rpm, 32 mph at 4000, and 24 mph at 3200 rpm.  With the 24" I was 44 mph at 4800 rpm, 28mph at 3200 rpm.  Going from memory on some of these numbers but I know I am pretty close.  I think the fuel usage will be a trade off as it doesn't take as much to get on plane or to stay there at lower speeds.

[alex]

Thanks for yr reply Dale M.

Checking the propeller while trailered the boat this weekend, i noticed that the figure 22p, stamped on it.I assume that actually my propeller is 22'', but unfortunatelly i cannot reach your performance.

Please note performance in absolutelly flat sea with optimum trimming of boat:
1 person onboard, 1/4 fuel, 1/5 water, gen5kw: max speed 36-37mph @ 4800.
getting on plane @ min 3700 with a speed of 26.If i go less than 3700 i get off plane.

It looks impossible to reach 5000rpm and of course the speed of 42mph.

Any ideas why i have such pure performance? maybe the 22p does note mean 22'' propeller?
Maybe something is wrong with the engine?

The bottom of the boat is acceptably clean.

Apreciating any replies

Alex.

[DaleM]

Are your props installed right?  Bravo 3 props must be installed correctly.  It may be something as simple as that.  It's called indexing.  Be sure to put the inner prop on one blade straight up and the outter prop on with one blade straight down.  Properly indexed props will move a boat more efficiently.  Try this first.  Then look into the engine, change the plugs, cap, rotor, wires.  Put some injector cleaner in the fuel tank. 

[alex]

Thanks for your guidance Dale M.

I will check all your recomendations and revert.

alex