Correct material for Dry Riser for engine exhaust...

Table 1 in the same Article specifies allowable materials for exhaust systems. The dry exhaust list specifies aluminized steel, carbon steel, nickel-iron chrome and stainless steel. No galvanized steel, no brass, no bronze.

Reference: http://www.ntsb.gov/Dockets/Marine/D...012/234864.pdf

This is the idealised recommendation from the Perkins Sabre installation manual;

"The general arrangement (A) shows that the dry part of the system extends to a safe height above the water line, using an elbow (A1), a stainless steel bellows (A2), a riser pipe to give the required height (A3), and a further elbow (A4), which is supported from the deck head by a flexible hanger, which supports the weight of the system but permits movement side to side and fore and aft."

"The minimum diameter of the dry part of the system should be 40mm (1.6”) for the M65 and the wet part of the system should be not less than 63.5mm (2. 1/2”).

We will see how close we can get. ANY and ALL recommendations and advice graciously accepted.