Prop advice... need more stern lift... Add hydrofoil?

[pjbrownva]

Originally Posted by spareparts

generally speaking, the higher up you can run the engine, the more efficient it will perform, but with everything, there will be trade offs. Easy way to check it, have someone run the boat in a normal fast cruise and trim position, look over the stern and see if you can see the anti-ventilation plate on the engine(the thing you bolted the fin to). It should be just out of the water at a good fast cruise and proper trim position. The fin should be skipping across the top of the water. Be careful, don't fall in. If you have time to play with it, raise the engine up till it blows out in turns then go one hole back down. The higher you raise it, the less leverage you will have

Thank you. I was considering putting a jacking plate on the boat, but was then advised that they aren't recommended on this type of salt water boat.

I don't know if the additional setback from a jacking plate would be a help or a hindrance.

I did note that Suzuki took a victory lap for designing the outboard to move the center of mass of the motor further towards the bow... which definitely had me wondering if a jacking plate is a good idea or a bad one.

Opinions are welcomed, and facts are GREATLY appreciated.

[SkunkBoat]

I ran a zuke DF140 on my v20. Stainless 3x14x20 prop...perfect...no trim tabs

[pjbrownva]

Originally Posted by SkunkBoat

I ran a zuke DF140 on my v20. Stainless 3x14x20 prop...perfect...no trim tabs

Wow! Do you remember how many RPM's you could turn with that prop?

I'm thinking that if I raise the engine height some, I'm likely to get more speed and higher RPMs, which might even allow me to go from my current 17 pitch prop up to a 19 or 20 pitch prop... assuming that I could still reach the recommend max RPMs at full throttle. I've read that these 'zuki 4 stroke engines like to be able to rev, and don't do too well when they are over-propped.

[SkunkBoat]

This is from an old post

"It's a Suzuki 3 blade stainless 14 x 20. It has vent holes at the base of each blade. It's the original prop that the dealer fitted when he installed the motor. I run fairly heavy, with lots of rods, gear, anchors, coolers, and always 30 -55 gallons of gas. The hard top adds some weight too. At WOT, light, with motor trimmed up perfectly, she will get to 6000rpm and ~38mph. But I rarely do that. When I'm in a hurry I'll run at 5600 rmp, just shy of WOT.


Do a search on the Tag "DF140" for more info.

zukes have a 2.5:1 gear ratio. They need a big prop. I suspect you have the 17" prop trimmed in too deep to keep it from overrevving. 17 is too small.

You should be able to run fine with no tabs and definitely without a fin.

And the manufacturers have a range for WOT for a reason. Don't stress about getting to the max of the range. Get the boat to perform well out of the hole and cruising.
Testing should be done without tabs and fins and crap.

[pjbrownva]

Originally Posted by SkunkBoat

This is from an old post

"It's a Suzuki 3 blade stainless 14 x 20. It has vent holes at the base of each blade. It's the original prop that the dealer fitted when he installed the motor. I run fairly heavy, with lots of rods, gear, anchors, coolers, and always 30 -55 gallons of gas. The hard top adds some weight too. At WOT, light, with motor trimmed up perfectly, she will get to 6000rpm and ~38mph. But I rarely do that. When I'm in a hurry I'll run at 5600 rmp, just shy of WOT.


Do a search on the Tag "DF140" for more info.

zukes have a 2.5:1 gear ratio. They need a big prop. I suspect you have the 17" prop trimmed in too deep to keep it from overrevving. 17 is too small.

You should be able to run fine with no tabs and definitely without a fin.

And the manufacturers have a range for WOT for a reason. Don't stress about getting to the max of the range. Get the boat to perform well out of the hole and cruising.
Testing should be done without tabs and fins and crap.

Thanks for all of the info, @SkunkBoat. I've taken a break to hibernate for part of the winter. :-)

I plan to get back on the water in March, and continue this tuning. I think you're right about needing more pitch and raising the motor height. I *think* I have a 19 pitch Solas 3 blade SS that I ordered and tried for a short while.... so it's basically new. I guess I'll go back to that, raise the motor and report back.

'Til then, wish me sweet dreams! (hehe!) Hibernating is fun!