CaSam et al…..
This isn’t a new problem. I had exactly the same failure about four years ago on my B32 ‘Another Fantasy’, which I reported on the website at the time. (Unfortunately the old posts seem to have disappeared from the ‘new’ site). When the muffler first began leaking (just a slight weep, in fact), I had the seams re-welded by an engineer in Chichester Marina. This was quite effective to begin with but after a while the same problem surfaced again, so winter-before-last the engineer fabricated a new muffler end cap from thicker and supposedly better quality steel. This seems to have cured the problem thus far; no sign of any breakdown and the welds are holding up and was cheaper than buying a complete new silencer!!
The muffler isn’t the only point of failure in the exhaust system. I’ve also had to replace the exhaust elbow (the heavy casting which connects the exhaust pipe to the manifold and which incorporates the cooling water exit from the heat exchanger.) The casting had corroded from inside, to the extent that cooling water and more worryingly exhaust gas was able to escape through a small hole which appeared at the bottom of the casting. At least there was prior warning of this failure: rusty water dribble marks on the side of the cylinder block, adjacent to and below the elbow. I’ve taken the precaution of fitting a carbon monoxide detector in the aft cabin, should the same thing happen again.
Unfortunately we’re at the mercy of the laws of physics and chemistry: some metals and sea water just don’t mix very well…..since these problems occurred I always check the engine for any sign of leaks. It helps if you try to keep everything scrupulously clean.
B32 Another Fantasy