Abstract
In order to cope with recent development in making lighter the hull of high speed boat special efforts are generally being given to reduce the weight of engine outfits.
In line with this tendency the shipyard is also endeavoring to reduce the weight of exhaust pipe & muffler on torpedo-boat and hydrofoil vessel, coupled with such the parts as tank, pipe & strainer etc. & has decided to go ahead on this direction.
This is based on the result of test effected previously (aluminium alloy exhaust pipe did not show any deterioration after several ten hours testing in 12 WZ type engine) as well as of the intermediate observation of trial test of the boat "Arakaze, " ensuring the possibility of adopting light alloy for such purposes.
This report comprises therefore the test result of exhaust pipe in the light alloy boat "Arakaze" which serves as marine guard, the property of the Marine Safety Agency.
After using for 6 months at about 370°C of exhausting temperature the inside of jacket has been examined. Neither was abnormality observed under macro-inspection nor under microscope.
Also, although the region directly contacted to high temperature was found mostly sooty, no deterioration at all. But a slight unusual condition was observed around the inlet part of exhaust pipe that appeared even so slight as to make no difference to the case of iron exhaust pipe.
Consequently, should aluminium alloy pipe be solidly anodized, careful in welding & fixing, attentive to electrolytic corrosion, aluminium alloy can be used adequately as the material for exhaust pipe & mufler on practical application.
