Iron Oxide Blasting Grit. Engineers Enemy.

Macphail
16th May 2009, 23:00
Dry dock in Sembawang,

Due to all the surrounding grit blasting the atmosphere had a gritty feel to it.
We had exposed two intermediate shaft bearings for survey. All correct and in good condition. Boxed up and sailed. Cleared the Singapore pilot and went on our way. Over a gradual period the bearings started to run hot. Water hose, moly slurry. no good, in the end, stoppage at sea, jacked the shaft up, removed the bottom half’s, found to have fine particles of blasting grit impregnated in the surface, scraped and bedded in the bearings, boxed up and got under way.

I do feel that the effect of blasting grit on machinery is not taking into account during a dry docking period.

Anybody else had a bad experience with blasting grit.


All the best,

John.

surfaceblow
17th May 2009, 01:45
During a dry docking the sea valves were open while the hull was being blasted. On my walk thru the lower engine room one of the plywood pieces covering a sea valve overboard opening flew by when a blaster hit the wood. The resultant mess had sand blast in the purifier sump, and bilges.

Later when the blasters did the cranes the oil sight glass broke causing the 40 ton crane hydraulic sump to fill with sand blast grit. The cab glass was also damaged has well as the seat. The Chief Mate was told by the Port Engineer in my presence not to move the crane until either the First Assistant, Chief Engineer or Port Engineer said it was alright. Instead of just cleaning the sump and flushing the system all of the hydraulic motors had to be overhauled and the control valves opened to replace the o rings and check if any valve spools were scored.

eldersuk
18th May 2009, 00:23
Not so much blasting grit but calcine. This is coked bauxite which we carried on the Sunjarv. It is also the material used to make grinding wheels!
We used to load this in Mackenzie, Guyana and had to seal off all engine room doors and skylights with sticky tape. The accommodation was similarly sealed off and with no air con the ship was a hot'un.
Even with all these precautions when it came to a run up the road weeks later you found all the pockets of your go-ashores were full of the stuff.

Derek

JoK
18th May 2009, 00:39
Sitting down in the mess, one morning with a coffee,waiting for my replacement to show up. Ship was on the dock, everything buttoned up and the hull is being blasted. Next thing the engine room alarm is screaming, then the fire alarm goes off. I go scooting to the open engineroom door and look down. It is like looking at a dust storm. The fellow blasting was shooting in the seachest with all of the sea suction valves apart.
Too bad #4 engine was also apart.
I have always strongly discouraged engine work on the dock after that occasion.