will it fit??????

[mercdrag]

will a 16" diameter prop fit on an outboard?? if not what is the biggest? thanks

[msm]

I just measured my 2.5 litre torquemaster and it's 8.125 from the center of the propshaft to the bottom of the antiventilation plate. I don't know about all the other gear cases though.

[mercdrag]

thanks my sporty is the same....I just dident know if there is a min on clearance you need from the tip of the prop to the cav plate.
has anyonne ran a big prop like that on a full tunnel?

[Hottrucks]

NO and why would you??? to hard to turn

[mercdrag]

let me give you alittle more info on my setup. 21' cat with a drag motor witch is not the best motor for a big tunnel. the prop it has liked the most to date has been a 15/24 pitch cleaver. it has great topend but slow in the midmange and with the rpm range the drag has I was thinking of a 16/22 the big blade to carry the boat and a small pitch to spin eazy and run the motor higher aswell @ high speeds. any 1 ever try that??

[jphii]

I tried a 15 1/2" prop once. Only once, didn't work too well.

[mercdrag]

I tried a 15 1/2" prop once. Only once, didn't work too well.

what kind of boat did you try it on and what dident you like?? thanks

[jphii]

An OMC on my old Seebold. Even with the grunt of an OMC it had a hard time getting out of the hole. The only thing it did to well was top end, but it took a while to get there. I actually tried it once on my Mirage too, but it was pretty much the same. And the Mirage comes in under 1350 with me in it running.

[150aintenuff]

outboards dont like that much diameter generally.. a 16 will fit but only in big houseboat applications are they used on outboards... and in like 11-13 pitch... for a 21 footer look to a 14.5X 24 or 26..

[Hottrucks]

If it was me I would think about regearing it
what do you have 1:87???

[mercdrag]

outboards dont like that much diameter generally.. a 16 will fit but only in big houseboat applications are they used on outboards... and in like 11-13 pitch... for a 21 footer look to a 14.5X 24 or 26..

thanks for the replys. the boat didnot like the smaller sizes. I tryed a 14.5/24 chopper, a 14.25/26 4blade cleaver and they didnot work aswell as the 15/24 cleaver in carrying the boat and not even close on topend.
and yes it has a 1.87. what are you thinking 2/1 ???

[Hottrucks]

2:1 will allow you to get more torque to the prop making it pull harder on the bottom and mid and like you said let it spin to get good top mph#'s... I think you would fingd that the boat would bew better in the common areas with only small loses in the top........

also you may try cutting down to a 14.5 X 24 this will allow more slip until the motor can spool up to the power ......
More info on
make of boat
setback
weight
then we can really help ya out

[pyro]

It's a Jones Tunnel.
Deep, heavy, roundy-nosed true cat with a big fixed tunnel tab.

Here it is, parked next to my boat.

[Wolverine]

Lots of blade area (oughta carry the boat real well) and a little less pitch.........sounds like a winning combo to me. You already tried about everything you could get your hands on with 14 1/2" or less in diameter and 26p on down with the best prop still being your 15" diameter cleaver........hands down. Big Daddy thinks ya should try that big rascal.

[pyro]

Have you guys ran it with anything else, other than the big cleaver and a round-ear? You need to really start a new thread called "21' Jones Tunnel cat setup" and see if you can draw out some experience from the few who have run one, or anything remotely similar. I have seen how the boat rides with four aboard, but I'm not sure I understand what you're looking to gain. More stern lift? More response to trim? a bit of both?

Have you ever run an ET or ET cut on it?