corrosion in steel pipe 8

[xyyy]

This is a fish hoist. Please see attached picture.
The top cap of main post is rusted away as shown in attached picture. There are some rust areas at the post bottom. The inside condition cannot be seen. I need to evaluate this hoist if it needs to be replaced, repaired, or still okay. The main concern is that because the top steel cap is all rusted away, water is trapped inside the pipe and made the pipe corroded inside. But I can not see the inside and do not know how to evaluate the inside condition. I used a hammer to knock to listen to the sound. I can feel the sound in the most corroded area is kind of different.

Any suggestion on this hoist's condition?

 

[JedClampett]

You've got two choices:
1) Hire an engineer to evaluate your hoist and recommend repair or replacement.
2) Replace your hoist.
I'll bet the second choice is cheaper. No one here will do engineering remotely.

 

[dhengr]

xyyy:
Boy, you must catch some really big fish. Cut the cap pl. off so you can inspect the inside of the column, it certainly isn’t doing any good any longer. You should then be able to inspect the upper portion of the column. Drill some 1/8" holes in the pipe column, in min. stress areas, to check the wall thickness. Drill a couple drain holes down at the base pl. You should not design something like that without providing drain holes at the base. I do understand that it is not your design. Then make some judgement about it strength, cap’y. w.r.t. the original design and condition. You could load test it to several times the cap’y. you stencil on it. Or, as Jed suggests, get a new one, and take care of it.

 

[Ron]

agree with dhengr....likely you have anaerobic corrosion on the inside at the bottom. Bad place to have it for such a crane. Replace it. As JC noted, cheaper to replace than repair for this.

PS...those are lousy gussets at the base.

 

[kingnero]

why are they lousy? because of their slenderness?

I think it's positive that no sand/salt can get trapped in the spaces between...

 

[SAIL3]

I would replace it with galvanized stl or SS and redo gussets @ base since they impart a conc load on the pipe as shown....

 

[Ron]

IMHO...the gussets are bad because of both points....kingnero's (too slender) and sai3's (concentrated load on pipe wall....punching issue with interior corrosion)

It is ok to cope the gusset at the pipe/baseplate connection to allow for cleaning and lack of trapping debris in corner; however, that only requires a small radius cope, say 2 inches.

 

[JStephen]

They do have ultrasonic thickness testers that will tell you wall thickness from the outside.
One option: Load test it.

 

[dicksewerrat]

Testing,interpreting and reporting may cost as much as the material for a new standpipe.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[xyyy]

Dhengr: Yes, the fish on some photos is probably more than 6' long and more than 500 lbs.

This fish hoist is about 20 yards away from ocean.

All, thank you for your recommendation. I will suggest to replace it.