How to glass in a shaft log?

Kevin3447 · Nov 22, 2011

Check these out: http://www.westsystem.com/ss/use-guides/
Also, they're really helpful if you call them.

Ross · Nov 22, 2011

Does the cutlass bear fit into the shaft log? . You cannot fit an 1 3/4 inch tube into an 1 3/4 inch hole. You must have a little clearance. What size is your propeller shaft? When I have had the need to make fiberglass bubes I wrapped waxed paper around a mandril and wet some very light weight glass cloth and made a first layer. When that got as hard as wet leather I added more layers. I think that if you set up on supports and have someone to turn the mandril while you apply fibergalss tape and resin it will go more smoothly than trying to work alone.

Allan12210 · Nov 22, 2011

You are not trying to fabricate a stern tube out of poly and bond it onto that thin section of hull are you? You will never get it strong enough to not snap off. Do you have any pictures of what you are trying to mount in the hole? Is it a standard stern tube that bolts from the underside of the hull, but is a smaller diameter than that hole? Are the holes in the "new" stern tube in a different location than the four we can see? I'm thinking you can locate and drill the holes for your new stern tube, then fill everything else with thickened epoxy. Like Ross says, wrap the entire stern tube with waxed paper or saran wrap so you won't glue it to the hull. Once it is cured you can remove it and use a sealant. I wouldn't use poly as a bushing to reduce the existing hole size because the epoxy won't stick to it. If you want, put a 1/4" thick plate of FRP over the holes and sandwich it between a new shaft log and the hull. The flange surface of the stern tube and bolts extending through the plate and hull will snug it tight. You can use Sikaflex to glue that on. Just make sure your primary hole is centered. This all assumes I am picturing what you are trying to accomplish correctly.

tommays · Nov 22, 2011

Having been there and done that IMHP making your own tube is a BAD idea as i had to change mine due to blisters from a bad original layup

i fooled around with a few homemade tools to cut the old one out

And cutting it out perfect was BAD because they did such a BAD job with the original hole it did NOT line up with anything EVER

The job is difficult enough starting with a perfect tube and i favor G10 epoxy tube as it is perfect in every way and will allow you to use bushings to line it up it for the glass work as there not much point glassing it in wrong

I used 1-3/4 OD X 1-1/4 ID to clear my 1" shaft

It has to be straight with the motor which is the hard part as it will require a true piece of shaft material to hold things still while you do the glass work and you cant move the motor all that much if you get it wrong

sailaway78 · Nov 22, 2011

Previous post

tommay is correct. get yourself a piece of fiberglass tubing the correct size. You can then line it up and glass it in. Much better than trying to make your own tube. A glass tube is readily available in almost any needed size, and pretty inexpensive.

Ross · Nov 22, 2011

A short section you can make.

tommays · Nov 22, 2011

You have to search as i found 2' from AIN plastic.

What is wrong with your log ?

Fred Villiard · Nov 22, 2011

You can try mcmaster.com they have fiber glass tubing.

Fred

Ross · Nov 22, 2011

Was this an old packing gland? Was it just a piece of 1 1/2 inch bronze pipe?

Stu Jackson · Nov 22, 2011

Stephen Trapani said:
The old bronze one corroded into bits.

Ross may be getting close.

If what you took out is the cutlass bearing, you don't want to replace it with "straight" fiberglass.

Some boats have struts with the cutlass bearing in the strut, other boats have the CBs in the stern tube.

You need to find out what your boat has before you do any of this proposed work.

Unless you KNOW already.

Allan12210 · Nov 22, 2011

Stephen Trapani said:
The old shaft log was a simple tube attached to a small plate bolted onto the outside of the hull. The cutlass bearing is in the strut. I want a shaft log out of fiberglass to attach my PSS shaft seal to. Maine Sail recommended it. It makes the most sense. I need a tube sticking about three inches into the boat.

McMasters has a 1 1/2" OD tube I could get and build up. Would that make sense?

I think this is going to be a difficult task. You saw the amount of effort that Tommay's put into achieving a precise alignment with his set up. Trying to build up a FRP tube is not going to make it easy to align. That and the fact that it could be aligned for the boat being out of the water. As soon as the boat changes shape after it is back in the water, then it could interfer with the fiberglass tube. In order to rigidly mount it, you need to pot it into enough material to fill around it like Tommay's but the hole is a lot higher from the bottom of your hull. That couldn't be done in a single pour as it will get really hot possibly even to thermal runaway. The flat surface of the hull where the old shaft log plate was mounted is still your best bet for a proper alignment. That flat surface is a reference plane that was designed into the hull to be perpendicular to the axis of the shaft. It would be best to continue to use it. The last bronze log lasted 32 years. A new one should be good until 2043. You can still mount the dripless packing to a conventional shaft log. A mechanical solution, even if you have to cut a flat plate of material to fit over the old holes will be so much easier. Good luck with whatever you decide.

tommays · Nov 23, 2011

http://www.buckalgonquin.com/pages/ProductPages/drivetrain/oval_rect_shaftlog.html

Seems like it would be a standard part ?

Maine Sail · Nov 23, 2011

tommays said:
http://www.buckalgonquin.com/pages/ProductPages/drivetrain/oval_rect_shaftlog.html

Seems like it would be a standard part ?

You can also try a company called "Marine Hardware" they make shaft logs and bronze parts as well. Another company called "Southeastern Foundries" they did/do a lot of the work for Hunter...

As for a glass tube you can make a square plate out of G-10 matching your existing bolt hole pattern with a perfectly sized center hole for the glass tube. Then epoxy the tube to the hole with cabosil thickened epoxy and next "tab" and glass the tube to the G-10 plate making the tubing a little longer than needed for the tabbing support area. You now have a square glass plate non-corroding glass shaft log.

As Tommay's mentioned this MUST be 100% aligned correctly with the strut and engine. This is a tedious and time consuming project to do correctly.

redhead78 · Nov 23, 2011

Steve can u buy a stern log with a stern tube that threads into it, say from algonquin... Red

Old Skool Neil · Nov 23, 2011

I won't carry on about it but having done many of these installations, my opinion is this is not an area to learn new skills.

Ed Schenck · Nov 23, 2011

I would do what Hunter did on my H37C. Use a new bronze shaft log as the mandrel for making a heavy fiberglass tube. Install the log with the bolts. Slip the f/g tube over the log from the inside and glass it to the hull. Naturally you will have made the OD of the f/g tube to match the ID of your PSS shaft seal.

How to glass in a shaft log?

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