Broken Davit Crane

[sixty]

Was launching my new tender this evening and the stand pipe failed on the davit crane right at the base plate to stand pipe connection weld. Luckily it broke in the one orientation where it would not cause major damage and I had shoring in place because we were in the process of bottom painting, I'm VERY lucky! I am not sure of the model and size of the davit but the shear pin is stamped 1000 and the Caribe CL14 with full fuel weighs in just under 900 so I figured I was safe.

The standpipe was only 1/8" wall aluminum tubing and the 3/16" weld heat affected zone would have weakened the tubing especially since post weld heat-treating would not have been likely. The previous tender was about half the weight and this was probably the 15th lift with the new tender so it was definitely fatigue failure. There we signs of flexing in the paint but no apparent cracks until this happened. I am thinking of replacing the tube with either stainless if I can find it here in Mexico or mild steel with good paint an then machining it to carry the rotation bearing. Any thoughts?

Can anyone ID the davit? There are no markings other than the 1000 stamp on the pin.

pics can be seen here since I cannot get them to upload even at very low res:

https://www.dropbox.com/s/o7pzwegxdvse239/IMG_20180709_182744.jpg?dl=0

https://www.dropbox.com/s/e8kv15ip7ukxl4t/IMG_20180709_182901.jpg?dl=0

 

[hoop1013]

WOW!!! I can't help with identification but I can tell you that I just replaced my davit on my 58' MY and used 1" wall thickness aluminum pipe. Should not be hard to find a good replacement.

 

[sixty]

Thanks Hoop for the reply. Where did you find 1"wall aluminum pipe? All I can find is 3.5" schedule 80 which is .31" wall and about 3x stronger. This is probably the route I will take.

WOW!!! I can't help with identification but I can tell you that I just replaced my davit on my 58' MY and used 1" wall thickness aluminum pipe. Should not be hard to find a good replacement.

 

[Glory]

My stand pipe is 1/4", gets used often.

 

[motoryacht lover]

No expert here but my guess would be Marquipt. Try sending them the picture and see what happens.

 

[oceanjake]

it's definitely a marquipt davit. They made a 1000lb and a 1500lb that look nearly identical.

 

[hoop1013]

Thanks Hoop for the reply. Where did you find 1"wall aluminum pipe? All I can find is 3.5" schedule 80 which is .31" wall and about 3x stronger. This is probably the route I will take.

If I recall correctly, it was sourced from Jarrett bay marine in Beaufort NC. 1" was definitely overkill but I feel confident that the boat won't suffer the same fate as yours. Best bet is to talk to Marquipt.

 

[sixty]

Thanks or every ones replies. I pulled the standpipe today and its actually .25" wall AL, just looked thinner because the material stretched at the weld. I am meeting with a local fabricator in the morning to see what he has and hand and discuss rebuilding the existing with reinforcing or sourcing some 4" .5" wall tubing from the states. Also considering some 304 stainless tubing.

Will keep you guys up to date.