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Good afternoon sandbox I’ve installed my shaft logs 2 inch I.D 2 1/2 O.D and my shaft size is 1 1/2. At the time it seemed fine 1/4 inch all the way around but after reading Capt Pats shaft log write up I see he says you want a 1/2 all the way around. Do you guys think 1/4 is enough or should I just cut the logs back out and replace. I already bought dripless seals and installed them. It will definitely suck if I have to cut them out and replace. Any input would be appreciated.

Personally, I like a substantial amount of material where the shaft comes through the hull, especially when I'm doing the glassing.

I was faced with the choice of going lighter or heavy then recommended on the tubes, as there was limited stock during COV0D. My area has lots of debris, flotsam, and jetsom, so went heavier and glassed them in heavy as well.


This brings me to...if you are doubtful of your log size being adequate, add a few layers of fiberglass removing all doubt. Prep n layup has to be quicker, ez-r, cheaper, and I would think just as good as cutting out n replacing.

I think the OP is referring to the clearance in the shaft log for the shaft, not the wall thickness.

It’s not that I’m worried about the thickness of the tube I glassed it in really good I’m more worried about the clearance of the shaft while inside the tube.

Ironworker wrote: ↑Oct 17th, '22, 09:06 I think the OP is referring to the clearance in the shaft log for the shaft, not the wall thickness.

Yes exactly

vince
I am really not sure BUT if you are lined up perfect and you have 1/4" all around that Obviously gives you "1/4"..."play". I think if your alignment went more than 1/4" out of whack to then make contact you would have more problems than just the contact of the log...

Like I said, I honestly dont know

Yes I agree with you and my alignment is pretty dead on. Thanks for the input.

Most of the glass tube logs I glassed in had about 1/4" clearance around, but I made sure not only the boat was blocked properly, but the engines were 003 or less to the shafts and struts before I glassed them in. Rechecked after floating for a day.

Thanks Bruce! I appreciate the help

I'm in the process of installing mine today. I have 2.5" x 1/4" thickness. My shafts are 1 1/2".

As others have said its all about the alignment. What kind of engines do you have?

Ironworker wrote: ↑Oct 17th, '22, 17:29 I'm in the process of installing mine today. I have 2.5" x 1/4" thickness. My shafts are 1 1/2".

As others have said its all about the alignment. What kind of engines do you have?

I have Cummins 330s I used a mock up block and aligned everything before I glassed it all in

My guess is that you'll be OK. I have the QSB 5.9 380s. My hull is extra stiff due to the way I rebuilt the boat so I suspect flex is not going to be an issue for me.

Bruce mentioned a very important part which is to recheck your alignment after the boat has been in the water.

Oh...the running clearance of shaft to log. At 1/4" all around...it should be good, it will depend on your alignment when glassing log in and how good the boat was blocked. A little twist on land that settles in the water can reduce that 1/4"...toss in some engine movement and hull flex under load.

carl trust me 1/4" all around is the tickets ,i did mine 16 years ago and still perfect.

If Bruce said it was good, I was good with that, your input is the icing on the cake!

Me...I was just thinking out loud. I'm not sure what my clearance is, seems like a lifetime ago glassing in those tubes.

Thanks guys I appreciate the feed back I’ll continue onward. I’m also on the hunt for a Cummins 330 long block. One of my motors was shot. Pistons were torn up and crank had scoring on it along with a cracked head. If anyone has a lead on a long block or fully built motor send them my way.

We built a model for the QSB 5.9 engines. Its done its job so if you or anyone wants it can be yours for free. Pick it up or pay for shipping.