Installing propellor shaft into steel boat

You cut the hole with a "laser"........ Yeah

There's not much to go wrong with a string though, it doesn't need aiming, mostly you stick a bit of wood out of the rudder tube or a bit of angle tacked to the transom & tie off to that & often there's a bulkhead stiffener or post to tie to fwd. String, water levels, 3/4/5 square... good to go. Jeff.

 

I was wondering what you guys think of welding a stainless steel tube into a steel hull, for the cutlass bearing and prop shaft to be installed into.
According to reading, theres nothing wrong with welding steel to stainless steel, but I wanted to make sure there isn't a major argument against this that I don't know about.

It would be nice to use stainless for the prop shaft tube and maybe even rudder system, cause theres moving servicable parts.

 

Do some googling and find the Professional Boatbuilder series on Engine alignment, shaft installations. Good series.

 

I just used Sched 80 steel pipe. I could have used 316 but it didn't seem worth the hassle.

No problems welding it, really, except that 316 distorts like you wouldn't believe when welded unless you're very careful. I had to line-bore my Sched 80 stern tube due to weld-induced distortion which I considered excessive. Hate to think how bad it would have been if I'd used stainless (and what a ******* of a job line-boring it would have been).

Lots of people use stainless for their rudder stock. On the advice of the designer I used plain 1018 cold rolled steel. Based on past experience, as long as I keep the paint & grease up to it, I can expect in excess of 50 years life. This, incidentally, based on *actual* real life experience as boats Tom built 50 years ago are still in service.

I've welded quite a lot of stainless in the course of this project but I can't say I like doing it. My preferred options are TIG, MIG and then stick simply to minimise the heat I pump in - sometimes (fillet welds come to mind) MIG is faster and less heat input than TIG, so it all depends.....

Also keep in mind that stainless and oxygen depleted salt water (say sitting in a stern tube for a while) can be a bad combination. Frankly I'd just use the Sched 80 pipe and pull a few coats of a good epoxy paint through it after the welding was all done. Probably last longer than you will.....

PDW