I have just joined a "new ship", to me anyway. I thought that this picture might raise a smile. It is a 25/30 bar discharge line from the main starting air compressor. There is a slight leak of air and condensate, and some one thought silicon sealant was just the product to fix it!!!
(Personally I call it silly Cxxx sealant)
It reminds me of the time I joined a ship and found all the engine room pumps were leaking heavily from the stuffing boxes. Investigation showed they had all been packed using wire reinforced valve packing intended for superheated steam!!! The pump shafts were all totally destroyed, by friction with the wire.
Someone told me about a ship he joined where the engineers had used wire reinforced superheated steam jointing on a low pressure saturated steam system. Of course superheated steam is totally dry and saturated steam is wet. The jointing turned into a soggy pulp and the wire reinforcing rusted through, and there were leaks everywhere.
Someone else told me about a Saudi Aramco jack up rig he worked on. Someone decided it would be a good idea to lubricate the jack up legs with Copaslip, and ordered several tons of it. Apparently it came in 200 litre drums. Most experienced Engineers know that Copaslip is an high temperature anti sieze compound and has absolutely no lubricating properties. (if you don't believe me , google "Copaslip" and see what the makers say!!!)
Another mistake is to use copaslip on fuel injection equipment (apart from the outside of the injector nozzle and nut to stop it siezing in the pocke). Copaslip contains large chunks of copper compound which are large enough to cause fuel injectors and fuel pumps to sieze if they get into the fuel system.
The only assembly compound permitted on fuel pipe work, fuel injectors, pumps etc is the aerosol Molybdenum Di Sulphide spray.
Molybdenum DiSulphide compounds such as MolyKote and Molyslip, unlike Copaslip, have extremely good lubricating properties. In fact they are so good that Salesmen used to demonstarte by getting Engineers to tighten a nut bolt as hard as they could, dry, and then lubricate the threads with MoS2 when the bolt was tightened again, because the friction on the threads was so greatly reduced, the tensile force created in the bolt was sufficient to shear the head off the bolt!!!
This illustrates how important it is to check tightening procedures and toques. Some things are specified to be tightened dry, some with ordinary oil and some with Noybdenum Di Sulphide. The tension in the bolt and the compression on whatever is being tightened will vary enormously for the same torque, depending on the lubrication used.
It is always better to ask a stupid question than to do a stupid thing.