No, the Vetus plastic ones don’t melt. Used them for more than 20 years without problems. The installation in a Bavaria has the muffler/trap well away from the exhaust, and Vetus recommend a minimum of 300mm – guess on my 37 it would be at least 3 times that. However, not sure the pot type would fit in the space. An alternative is the GRP units from Halyard Marine. They make tubular ones similar shape to the Volvo unit. Not yet measured up whether they have one to fit as my original one is still sound after 12 years (famous last words!) – but I do inspect it regularly.