Strange Main Engine Problem

[gauravdutta]

Hi I am a naval architect working for a consultant. Recently one of our big clients has come up with a a strange problem. The bolts on his Engine become loose every 2-3 months and he has to go for tightening. This is a big ship, L>125m. The only hint he has given is that the Main Bearings get overheated and there are some excess vibrations in the ER. But I am clueless abt the solution to the problem.

[jdawes]

Gauravdutta
first thing that i would do is make sure that your engine alignment is correct you do this by droping the shaft and measure the clearence of the coupling to your engine. Should have about a 3' tolerence check side ways and up and down if this is all ok i would check that your shaft has not got a bend in it. other things to look at are the engine mounts, props out of balance.

[gauravdutta]

hi jdawes...
thanx so much for the reply. can you please explain the procedure in detail. I am basically a Hull man, Engine issue are quite alien to me

I was thinking that the Engine Girder Web is weak leading to vibrations. There could be some issues about the Thermal Expansion of the support structure.

MAN (engine manufacturer) has come up with a few suggestions. I shall update the same on Monday.

[Landlubber]

For such a vessel, certainly invest in Rotalign and Optalign type laser alignment tools and bed weight gear.

They are capable of identifying alignment of equipment in situ, as well as doing engine bed load calculations and amounts to shim to correct the errors, and there will be!

[Landlubber]

http://www.lazertech1.com/products.htm

these fellas may help