Adding strakes to JC Neptoon 21TT, reprop, motor height

[Bryden24shp]

The Mirage Plus is a stern lifter. You'll notice you won't need as much trim. The boat should run pretty high out of the water and the bow won't fly very high. But you may be surprised with your results. Keep me posted. I still haven't heard from Mercury (imagine that) on this prop I just ran. It compared very closely to a Mirage Plus, with the slight "pimple" on the blades. I do know it sure hooks up! 5% slip with the cav plate that high out of the water is amazing. I wish I could swing a jackplate right now, but all my $ is going into a new home for my boat and EzFender business. Breaking ground tomorrow! Can't wait!!!

[jayw]

Thanks, Ken was adamant about the Mirage Plus for me and he seemed to echo what you are saying about lift. My boat naturally "bows up" a bit anyway - my nose cones ride a bit high - it's not a flat running boat - so hopefully the Mirage Plus' lift will be a great fit. Ken seemed to think it will.

Believe it or not that aluminum Suzuki seems to stern lift more than the PT did. It has really big round ears with flat cupping. Not much bow lift but it does stand up. Of course that DF150 flexes that thing like crazy esp with the 2.5:1 ratio so I lose 2-6 MPH depending where you are in the power curve. With that of course it sucks in the chop. I kept falling off in the swells and clipping the nose cones. Even my wife who is largely oblivious to it all thought the boat rode badly so looking forward to getting back to SS. That said even it seemed the AL was getting better fuel economy than that PT was at the end, that's how bad that PT got.

By pimple you mean the cup? I thought the Mirage Plus had some cup just not so much. One thing for sure when I take out a crowd I am not letting people front load the boat like they do. I stil wonder how a Rev4 would do, but I am afraid to lose any top end. It's too precious a territory to give up.

After all this prop fussing I told my wife I want a Playcraft Daytona. She wants to wait a few years. Now, $2k on strakes doesn't seem so out of line to her. Probably need a new prop AGAIN if I do strakes! We'll see.

I will post results & observations once I run the new prop. Keeping my fingers crosssed. Swapping props is a bit of a pain for me with our storage setup: change prop & wait up to an hour for a launch.

[jayw]

I am finally going to run the boat tomorrow with this Mystery Prop that Mercury sent me last fall to run. Its supposed to be an ECO, but it is not stamped. It looks like a cross between an Enertia and a Mirage Plus. Its a 17 pitch. Has a hell of a cup to it! I have to get hold of the Merc Rep who gave it to me to find out what the hell he sent me, after I run it.

For kicks what 4 blade would you recommend for my setup? I'm gonna try to get 1 from Ken. Not sure if I want to go with Powertech or just do the Rev4. I rad your post about the vensura, crappy results with that one huh?

[jayw]

Tested a Quicksilver Thunderbolt (aka Mirage Plus) 19P. Did OK. Alone hit 6K RPM, about 38 MPH. I expected more impressive results but it does have a ton of lift and nice handling. Have to see how it does under load. May fall off fast. Having it tweaked anyway (out of balance out of the box!) plus I already ragged up an edge (long story) so I may have the P shaved a bit and a little tip cup added for more bow lift. Don't want to go too nuts with it though.

[Bryden24shp]

Tested a Quicksilver Thunderbolt (aka Mirage Plus) 19P. Did OK. Alone hit 6K RPM, about 38 MPH. I expected more impressive results but it does have a ton of lift and nice handling. Have to see how it does under load. May fall off fast. Having it tweaked anyway (out of balance out of the box!) plus I already ragged up an edge (long story) so I may have the P shaved a bit and a little tip cup added for more bow lift. Don't want to go too nuts with it though.

Whoa, thats 34% slip! Could just be a bent blade causing the vibration and excessive slip. A little more cup will cut down on the slip. Sounds like you are getting closer, though. How was your engine height? Did it sound like it was ventilating?

[jayw]

I won't be adding strakes to this boat, least not the factory ones. JC recommends either remove the toons for the weld job or replace with toons that have strakes installed. You can imagine the price tag. I would trade the boat in first.

In any event we're OK with it, for now at least, few yrs down the road we plan to upgrade to something with a much bigger motor.

[jayw]

Tested a Quicksilver Thunderbolt (aka Mirage Plus) 19P. Did OK. Alone hit 6K RPM, about 38 MPH. I expected more impressive results but it does have a ton of lift and nice handling. Have to see how it does under load. May fall off fast. Having it tweaked anyway (out of balance out of the box!) plus I already ragged up an edge (long story) so I may have the P shaved a bit and a little tip cup added for more bow lift. Don't want to go too nuts with it though.

Whoa, thats 34% slip! Could just be a bent blade causing the vibration and excessive slip. A little more cup will cut down on the slip. Sounds like you are getting closer, though. How was your engine height? Did it sound like it was ventilating?

Engine remains 1 hole down. Needs to go 1 more. My summer marina lost a mechanic, they are so far behind. Then they raised their quote for the work to $180 which seemed high. I told them just don't bother, in six weeks the boat goes back to the JC/Suzuki dealer and we'll work it out there.

As for the 34% slip, no, my engine is a 2.5:1 gear so the slip is 12%. Still higher than I'd like, I'd like to be under 10% slip. We'll see what happens after I lift the motor. This engine could easily turn a 21P SS prop and still be well into the MFR WOT range. I might gain up top, I might lose, but I would most certainly suffer a lot more RPM loss with a big crowd. I will stick with the 19P and get it cupped, if the motor lift works out.

Oh yeah, the prop came back. It was WAY out of balance. One of the worse Rich Junker has seen, he told me. Thanks Merc. 3 different prop shops have told me that Merc props are not in balance all the time these days. Seems to me for $400-$600 you would get a little better workmanship that way. Hmmm. Still it is a better prop than the Powertech I had, that seems clear.