Prop hub question?

I'm looking for a spare prop for my boat and most everywhere I look they suggest a soft rubber hub instead of a FloTrque hub since I'm running a pontoon boat. Can anyone tell me why? I would think that it would spin easier under the heavier load of a pontoon.

Thanks

Re: Prop hub question?

The last prop I bought was a Turning Point Hustler for my 90 hp engine. It is my first prop with the Flo Torque (I guess) hub. The hub is plastic and is molded around a brass hub that has several radial spires coming from the hub that the plastic is molded around.

If you hit something, I don't see how the hub can take the blow, nor do I see the ability of the hub to soften the impact of gear shifting.

Rubber on the other hand gives when you shift gears and slips when you need it to slip and recover afterwards....to keep you off the rocks.

It's kind of like having a shear pin of yesteryear. Once you whack it you just lost your props ability to move water. Just my 2 cents but I bet I'm right.

Soooooooooo what's behind the industry's big push for plastic hubs? I don't think I like them and don't plan on buying another prop with one.....if I can find it.

Now what this has uniquely to do with toons beats me so sorry but I can't help you there.

My 2c,

Mark

Re: Prop hub question?

The square bore props came about for (first) the manufacturers benifit. In the old days a prop manufacturer had to make and stock a given prop with a hub for each manufacturer. The end result was a lot of props in inventory which takes up a lot of resources and space. Going to a square bore allowed them to make 1 prop (that same given prop) and stock several kits so it worked on different brand motors. Less inventory, less space, less resources invested.

The other benifit was that some of the larger hp motors have very high exhaust temps and can in some cases actually burn the rubber hub. The square bore kit sleeves won't burn.

There was concern about the sleeves not slipping and causing issues. We really haven't seen any such issues. About the worst issue is what's commonly (and incorrectly) refered to as "prop knock". The 4 stroke motors can make a clunking noise at idle at a low idle. Has a lot to do with power every other stroke and the gears loading and unloading the engagement lugs. A little irrating sometimes but doesn't hurt anything.

Re: Prop hub question?

Dhadley said:

The 4 stroke motors can make a clunking noise at idle at a low idle. Has a lot to do with power every other stroke and the gears loading and unloading the engagement lugs. A little irrating sometimes but doesn't hurt anything.

Click to expand...

My 2 stroke 3 cyl Merc does the same sort of thing at idle in F with my Ballistic 24P XP SS prop (rubber hub). If I use a lighter prop with less pitch I hear nothing...but like the 4 stroke and number of hits per rpm, my triple is a rough idler and the extra load of this prop aggrivates the condition...........Buttttttt I wouldn't trade the performance for all the knocking in the world and I can bump the throttle up to around 1k-1.2k and it smooths out just makes hitting the trailer just right a little tricky; but that's ok too.

Mark

Re: Prop hub question?

Dhadley said:

The square bore props came about for (first) the manufacturers benifit. In the old days a prop manufacturer had to make and stock a given prop with a hub for each manufacturer. The end result was a lot of props in inventory which takes up a lot of resources and space. Going to a square bore allowed them to make 1 prop (that same given prop) and stock several kits so it worked on different brand motors. Less inventory, less space, less resources invested.

The other benifit was that some of the larger hp motors have very high exhaust temps and can in some cases actually burn the rubber hub. The square bore kit sleeves won't burn.

Click to expand...

Sir, since you have joined this thread, would you care to comment on this type of prop hub's ability to stand a good whack. Does it strip out rather than slip as I surmised?

Thanks,

Mark

Re: Prop hub question?

We deal with a lot of flats boats (mine included) which hit quite a lot. We have not seen the square bore sleeves burn or spin. I have one customer who has rounded a sleeve twice but we can't figure out how he does it. The prop is worn but not full of whacks like we suspected. We believe the inside of the prop may not be in tolerance, may not have been from new. We don't really know.

Now, believe it or not the guys in the shop just brought me a prop with the sleeve shreaded! All that's left is dust. The prop is new and perfect. Stand by, we'll try to figure it out.....

Re: Prop hub question?

I wonder how many people don't get the hubs tightened properly. They have to be torqued down properly to get the square part of the hub up inside the prop.

Re: Prop hub question?

Looks like that's exactly what happened. After talking to the customer it looks like they dindn't tighten the nut enough. The drive sleeve wasn't seated all the way, probably cracked first and then shreaded.

Re: Prop hub question?

Dhadley said:

Looks like that's exactly what happened. After talking to the customer it looks like they dindn't tighten the nut enough. The drive sleeve wasn't seated all the way, probably cracked first and then shreaded.

Click to expand...

Moving right along, my service manual for my '02 90 hp Merc says 55 ft-lbs for a standard prop....rubber insert I suppose. Don't remember if my Turning Point had a notice in the box telling me otherwise. So is the torque the same or different?

But still, the rubber can take a whack and recover. The other type it seems has nothing with in it to give to it so it just transmits the shock to the gear train???????

Thanks,

Mark

Re: Prop hub question?

Bump