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Re: Top speed performance issues etc

Posted: Wed Mar 14, 2012 7:48 am
by gavman
Fuel is fresh in the tank and its only a 24 Lt tank - will try the stop to stop test - thanks.

Re: Top speed performance issues etc

Posted: Wed Mar 14, 2012 10:05 am
by raycarlson
as far as your water line, all M's sit 3-4" low at the bow with full ballast.reason being that 70% of your ballast is forward of your dagger board.definately drop down an inch in pitch.I second the running on an empty ballast,have no fears on decent water.i only flood tank when under sail power.

Re: Top speed performance issues etc

Posted: Wed Mar 14, 2012 10:33 am
by Divecoz
Ahhhhhhhh do ya think? I have too much stuff on board my boat behind the DB hahahaha YEP! been fighting it for years hahahaha
My error .. Yes your bow should be a little down when ballast is full. SORRY.. when you think about how much more hull I have dragging in the water with the aft being low? Hummm Heck wid it.. she still moves under sail :D
raycarlson wrote:as far as your water line, all M's sit 3-4" low at the bow with full ballast.reason being that 70% of your ballast is forward of your dagger board.definitely drop down an inch in pitch.I second the running on an empty ballast,have no fears on decent water.i only flood tank when under sail power.

Re: Top speed performance issues etc

Posted: Wed Mar 14, 2012 11:02 am
by dlandersson
Tossing the MIL over the side is usually good for an extra knot or two. :P
raycarlson wrote:as far as your water line, all M's sit 3-4" low at the bow with full ballast.reason being that 70% of your ballast is forward of your dagger board.definately drop down an inch in pitch.I second the running on an empty ballast,have no fears on decent water.i only flood tank when under sail power.

Re: Top speed performance issues etc

Posted: Wed Mar 14, 2012 1:45 pm
by aya16
You did your test run with full ballast? Than it sounds about right, speed that is. bow down an inch or so? normal with full ballast.
I take it you never had the boat in the water before. So you have nothing to compare by. 10 knots with water ballast, that's about it.

if you prop your motor to get 5500rpm with full ballast, than you will over rev, with empty ballast. These boats were made to run without ballast while motoring. Sailing, you put it back in. Come on you guys you know this.....
Mike

Re: Top speed performance issues etc

Posted: Wed Mar 14, 2012 1:50 pm
by gavman
Many thanks for the reply, all the info i have gathered from the other forum topics and also the service manual suggest the ft50 get yamaha should have a 14 x 11 prop not the 13 5/8 x 13 which it currently has, several people have reported that with the 13 pitch they get 4500rpm max and 10 kn max (same as me) but when they changed to the 14 x 11 they get enough power to get up on the plane and thus the speed increased to 15 kn +/- and reduced fuel consumption. yamaha also say that you shouldnt run the engine with a prop that cant achieve design WOT so i think i am going to change the prop and see what happens, relative to the cost of the boat it isnt much to spend ....

Re: Top speed performance issues etc

Posted: Wed Mar 14, 2012 5:51 pm
by Mac26Mpaul
As to ballast under power. These boats are perfectly safe under power with no ballast. They are not going to go over unless they get to about 60 degrees or so (just like all the fishing type half cabin etc trailer boats out there) If you put say 6 x 200 pound guys up on deck and got them to hang out the side, then did some real sharp turns, perhaps you might get it to go over, but honestly I wouldnt be worried...
We hardly ever motor with ballast in ( would be just a waste of fuel if you ask me) and my wife and kids are often sitting up on the foredeck.
If you're planning on going out in 3 or 4 metres of swell, then I'd probably put the ballast in first (just as an extra safety measure), but in normal conditions this boat was designed for, you just dont need ballast in under power.
Perhaps the manual has changed. I remember mine saying something about not having too many people on deck when you were motoring with ballast out.

Some guys have been known to sail these boats with no ballast in, but that is a bit silly if you ask me....

Re: Top speed performance issues etc

Posted: Wed Mar 14, 2012 6:30 pm
by mastreb
The manual for the 26M says no more than four people/600 lbs. for motoring without ballast.

I would not motor with the main up without ballast either, as many of us do for stability.