Shaft Strut

[rappareems]

I put a new three blade flex-o-fold prop on my boat last year and this season have noticed some cracking in the hull where the shaft strut goes in to the bottom of the boat.  There was water in there (obviously) when I pulled the boat the other day.  It seems to be a crescent shaped crack on both sides of the strut a few inches above where the strut enters the hull aft and arcing down to the bottom of the hull.  I was wondering if the torque of the folding prop put enough strain on the strut to cause the cracking?  I did some rudder repair last year and noticed that someone (previous owner) had drilled in that area from the bottom up and filled in with a type of caulk.  Any ideas?

Mark Cassidy

Mark Cassidy
#232 1986
"Rapparee"

[Ran139]

Mark,

  I am watching your post with interest because I am planning to pick up a Flex-o-Fold this winter at the AC boat show.
  I read previous posts on the prop and saw something that might be worth checking. The distance from the prop to the strut should not be excessive. The post considered 3.5 inches to be excessive. I would suspect that kind of distance creates whip and side load on the strut attachment points.
  Happy routing and filling!

[Bruce Fowler Registered M]

I hauled Sheer Bliss,#1055, last year to install my Flex-O-Fold and also had bad cracks.  It was not the prop.  The yard recommended that I install a stainless steel shaft which I did.

[rappareems]

I have a stainless shaft. The prop hub is maybe a little more than an inch from the strut, can I cut say 1/2" off the strut?

Mark Cassidy
#232 1986
"Rapparee"

[rappareems]

Further, I drilled a hole in the bottom about seven inches forward of the rudder and drained a good quart of clean water out, can't find the source.

Mark Cassidy
#232 1986
"Rapparee"

[rappareems]

Thanks Ron, I meant the shaft, would be a bit of a trick messing with the strut!

Mark Cassidy
#232 1986
"Rapparee"

[Denny #142 86 Turning Poi]

I have had the same problem of a crack around the strut with water inside also.  I suspect that over time cracks due to vibration can just happen.  I have the orginial equipment prop, 15 10 1, but a stainless shaft.  Still happened.  I had a local yard grind the crack out and refill it.  Well worth it since I seem to be a hack at critical fiberglass work.