Leaks at Propshaft Strut Screws

[neilpride]

Previous owner glassed the strut to the hull!! not a good idea, you can reach the boatyard with the strut in this condition?? in my opinion better to grind away the fiberglass in the strut, take off the strut, clean the area well ,check if the shaft is straight with the coupling, check the condition of the cutlas bearing , and if everything looks fine mount the strut in the original builder way, lots of 5200 new screws with bolts etc...and forget put fiberglass in the strut!! is just my opinion mate.... Cheers.

[osirissail]

From the photo on a sister boat, the only reason for the previous owner to glass over the edges/top of the base of the strut was because he had a previous leak and did not want to remove the strut and fix it properly. Possibly the mounting bolts were broken and he thought glassing over the base of the strut would hold things together long enough to sell the boat.
- - The strut has to be mounted so that it aligns the cutlass bearings exactly with the prop shaft hole. You need to observe the prop shaft very carefully when you remove it from the boat. If the strut is not in the exact correct place you will be inducing a rapid wear pattern on the cutlass bearing in the strut and any that might be in the hull. Although there probably isn't any cutlass in the "shaftlog" which is the hole in the bottom of the boat that joins with a fiberglass tube inside the boat. The stuffing box or dripless shaft seal is mounted inside the boat on the shaft log. I would guess that you have only the cutlass in the strut; the stuffing box and the transmission flange to hold the propeller shaft.

[Cheechako]

NeilPryde has it right. Do specifically like he said. Like you say , let the yard do it, but make sure they know how to do it right! You cant always assume that!

[clearsea]

We had this problem in a new to us older boat. Ground out the cracked epoxy over the strut, undid the four nuts inside the boat and easily disconnected the strut from the boat. That revealed why there was a leak: The strut base had only been sealed into the matching hull depression with a bit of silicone. We think water got into the fibreglass at a bolt hole and created a void between two of the bolt holes. We chased out the void, rebuilt the depression with hardened epoxy using a plastic mould, and reinstalled the strut with lots of appropriate sealant and new bolts. Glad I did not let it go longer.

[b-rad]

The boat is out of the water, I took some pictures. Any advice at this point is greatly apreciated, as of now planing on removing all the old epoxy, cleaning the strut and reinstalling with a coupous amount of 5200.

[osirissail]

There definitely appears to be a gap on the port side of the strut between the hull and the strut. Sometimes when a boat is barrier coated they paint over the base of the strut and then paint bottom paint over that. Then when the strut flexes a little as is normal underway, the barrier coat and bottom paint splits away from the area around the strut.
- - Is there a measurable gap between the base of the strut and the hull of the boat? Can you see the through bolts in that gap?
- - If the former owners had the strut removed and re-installed they may have installed a "putty pad" between the base of the strut and the hull to help get the strut into alignment with the propeller shaft. If that "putty pad" was improperly made it may have separated from the hull and worked it way out from between the base of the strut and the hull leaving a void or gap. That would definitely allow considerable "wobble" in the whole strut and propeller unit.
- - Either way, remove the strut and clean and re-work the hull where the strut is attached and have a proper "pad" built and then re-install the strut, etc. It is the "attention to detail" that makes the difference between a "quick and dirty" job and a proper job that will last.
- - This is also a good opportunity to have the propeller examined and re-balanced if necessary. Also check the propeller shaft for straightness and renew, repair or replace all the various cutlass bearings and stuffing boxes, etc. as necessary.

[Cheechako]

I cant see it really well but it looks pretty ugly to me. The strut should seat against the hull and fit "intimately". Based on what I think I see, here is what I would do: take the strut out of the way. Grind under to make sure you have nice clean fiberglass exposed. Estimate the thickness of gap between the strut and the hull with the shaft aligned pretty well. Wax the strut where it contacts the hull with auto paste wax. cut a few layers of fiber glass to rectangles a little larger than the strut. CUt holes in the glass rectangles so that you can get a few bolts through. These can be any bolts... you'll probably throw them away when done. Saturate the fiber glass with epoxy resin and stack them up thicker than the gap you observed. Put the layers on the strut with the bolts in place. Put this whole FIberglass/strut assembly onto the boat and tighten the bolts lightly and evenly. Leave it alone and let it harden. Next day remove everything, Carefully grind the edges of the glass cloth so it fairs into the hull well, redrill the original hole locations, sand or grind the wax off the strut, then assemble it with 5200 sealant and new bolts. Align your engine. You could just use "Kitty Hair" is suppose (Fiberglass resin/ cloth hairs avail at west marine etc) But the above would be the best way. If the strut actually fits well and there is no more than 1/8" max gap just in a couple of little places you could just use a bunch of 5200 I suppose.

[b-rad]

The strut fits in tight, I removed it today. There is just the flaking paint with chuncks of what appear to be resin/epoxy around the prop stut. Kind of looks like someone tryed to cover over the strut. Then again I dont have any idea what most boats would look like. The yard will be giving me a estimate tomorrow. Hope it doesnt kill me. Im really considering just cleaning then 5200 and reinstall.

[Cheechako]

If it fits tight and glass looks good after cleaning up all that loos stuff, then yea, new bolts and a lot of 5200. Snug it up tight and fair in the excess good.

[sailvayu]

The fiberglass and/or putty that has come loose is for fairing purposes only. But the fact it has chipped off like that indicates another problem. Something is causing movement of the strut. Have the shaft and prop checked for trueness. They both have to be removed to do this. If they are checked in the boat you will never be able to get a correct reading. The bolt holes for the strut have to be checked for proper diameter. If they are larger than the blots or elongated then you either have to use bigger bolts and re-drill the holes or fill the holes and re-drill. The strut has to be properly aligned to the engine and shaft. If there are gaps they should use a material call Chockfast to fill the voids not fiberglass. And of course the engine must be re aligned again with the boat in the water. I would also replace the strut bolts with new. And might as well put a new cutlass bearing in as well. Lube the wallet this is going to hurt. But you are better off to leave it to the pros but keep an eye on them not all yard workers know what they are doing. Makes sure they have done this before and do not be afraid to ask questions. Did you check with your insurance company? it might be they will pay part. worth a try at least.
Good luck
Wayne
Projectboatzen.com

[b-rad]

When I pulled the strut bolts the strut fell off, no sealant of any kind in there. I did have a bad vibration I think it rattled the strut loose. Should be fixed as I have a new shaft and a rebuilt propeller (and a new coupler and shaft log) to put in it. The bolts were in poor shape and will be replaced, if I ever find where to buy 4 inch 1/4 bronze machine screws.
So should the fairing putty be redone? Should I just grind down all the putty reseal the strut and then paint the hull ?

[osirissail]

b-rad go back to Post #4 for the link to a supplier of bolts and other fasteners.

[sailvayu]

I would grind out the old filler and refair with something like 3M high strength filler. You don't have to but it would look better and make for a more professional job. Glad you are fixing the original problem, sounds like you will have a good job of it when you are done. With luck you will not have to mess with this part of the boat for years to come.

Good Luck
Wayne Canning, AMS
projectboatzen.com

[Cheechako]

If the "fairing " is just to fair in the edge of the bronze strut... I wouldnt worry about it. You should be able to find the Bronze screws at a good old fashioned marine store, or a boatyard with a good store. I'm surprised they are only 1/4"...? Stainless nuts and fender washers are fine with bronze. Dont overtighten those bronze screws....1'4" will snap pretty easy. just good and snug. You should "dry assemble" your whole new componants (except prop) and make sure the alignment looks good from the packing nut to the strut with strut in place. In fact that will help keep the strut oriented properly when you goop it and bolt it. Make sure the engine end isnt too far off. Sounds like you are doing the right job!

[b-rad]

So what would I use grind out the old filler, Should it beobvious when I have the fairing gorund down, im scared im going to grind into the hull.
I grind down to bare hull. Install strut with lots of 5200 and new bolts
Then I refair with filler. Does the bottom paint just go on over the filler? Do I have to have a barrier coat?