Last summer, we heard knocking from under the stern port locker whilst under power, and discovered that three of the four metal/plastic brackets had sheared causing the cold exhaust to vibrate against the hull. Temporary brackets of shock cord was used, but we are having difficulty sourcing replacement mounting brackets – a flexible mecanno type material, sometimes known as a P bracket. Peters are unable to help. Has anybody found a suitable source for these brackets; 17 cms circumference, 5cm diameter. Aquafax sell packets of 25 -we want three ! We have only used our engine for 780 hours in the four years we have sailed 8,300 miles.