Yard to do Strut replacement for Aluminum Hull

Yank Marine, Tuckahoe, NJ
Derecktor, Mamaroneck, NY
Ocean Marine, Portsmouth, VA

Sorry, no experience with that in Baltimore.

Struts

How old is the boat

How many shafts have you gone through.

Stick with what you have

Deckelman's in Rock Hall can probably do it. I'd also call Anchor Bay in Baltimore. They seem to be able to do most everything.

This. Or, I worked on a 75' Jim Smith SF and it only had 2.5" shafts for 2000hp engines. This was because they were splined and didn't have the traditional keyway making them much stronger.

Here is an easy way for you to check the shafts yourself: Take a magnet in the engine room. Hold it against the shaft. If it is Aquamet 17 the magnet will stick. It will not stick to Aquamet 22. If you're going to repower in the future with higher horsepower, increase the shaft size and strength.

Call Mike's Mobile Marine Service 7629 Water Oak Point Rd
Pasadena, MD 21122 Phone: 443-463-2820
He can't do this job, but I had him do an emergency repair on the Hat recently and I'd trust his local recommendation.

Pulling the shafts every 2 years, if you've had no damage to the props is quite eccessive. 5 years is a good number. I wouldn't change anything right now. Have the shafts/struts aligned and leave everything else alone. Have the shafts dial indicated on the boat. If it lasted 25 years, it's fine. If you add more horsepower, keep the same shaft size and go to stronger splined shafts.

After doing several refits on aluminum hulls I've had my eye's opened on how the "metal half" lives and goes about handling pesky issues like shaft alignment and such.

In Fiberglass or wood construction, you have to nail the shaft line down when you install it and struts are bedded in to be within normal tolerance (.003" at the coupling end and no appreciable rotational resistance aft), all with cutlasses tight in the shaft log and strut. Of course some boats experience sagging or hogging when blocked vs. in the water but a short period ITW and a second check/alignment usually takes care of it.

Aluminum (and maybe steel?) boats seem to have a different approach. Their struts are usually overbored and a quad of setscrews on either end of the strut bore is used to align the cutlass bearing and a potting compound of epoxy is used to make up for whatever difference in alignment is present. Once the compound is cured, the set screws are removed and the project is finished.

If you have a reddish orange compound surounding your cutlass bearings you most likely have the same situation and need to completely remove it, drill and tap for set screws, align and pot the bearings in. The better companies doing this use laser targeting. Your shaft size sounds fine for the horsepower.

A very tight string and some disks can be used to check coarse strut alignment but are not so precise when looking for slight off axis errors in a bearing. We have found a laser setup to be much more accurate and you can shoot from both ends of the drivetrain to check how things are aligned.

I misspoke earlier when I said your shafts are adequate. I ran a quick calculation using Western Branch Diesels "The Shaft" size calculator. You always use WOT rpms, and with it you only have a safety factor of 2.591 with Aquamet 19 shafting and 3.182 with Aquamet 17/22. A safety factor of at least 4 is very desirable for your situation.

Here's a pic of our kit for shaft laser alignment, a set of inserts machined for different size bearings with a hole bored for a calibrated laser pencil to shoot the beam. It does require removing the shafts but it sounds like you need to do that anyway.

Philadelphia Resins Chockfast in there.

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