Leak between 2 1/2” and 2” outer prop tubes

[Coalman]

Hello Friends, need some advice pls. I have a small hairline crack around the joint between the 2 1/2” larger outside prop tube running thru the transom and the smaller 2” outside prop tube with the drip less shaft seal. Daily I pump out about 10 g/d sea water from the midship bilge. always the same amount.

Both tubes I believe are aluminum and are not magnetic. I believe the smaller 2” tube was slid into the 2 1/2” larger outer tube for some distance and then welded. Over time a hairline crack has occurred and began leaking. Any advice how to proceed with repairs, welding, brazing, Lock-tite, don’t worry about it, etc.

1996 Monk 36 Aft cabin trawler
Hull 179

 

[Comodave]

Do you have a photo of it? Is the leak between the 2 pipes? Maybe something like JB Weld. Or thickened epoxy.

 

[mvweebles]

Really need pictures. Both close in and a pic from some distance for context. Engines, size of shafts, etc. Why do you think it's coming from shifts vs rudders, etc.

10g per day is enough to be concerned about - half gallon per hour is a fair amount. Most gray hair owners on forums like this strive for a dry bilge, as in zero water so "don't worry about it" is the wrong answer except maybe in short term.

Unlikely your stern tube are aluminum. Perhaps bronze which also is non-magnetic.

Peter

 

[Nick F]

Most stainless is only very weakly magnetic. Are you sure that the material is totally non-magnetic?

 

[Comodave]

Try scratching the metal. Aluminum should scratch fairly easily S/S won’t.