C
catalac08
Guest
Tried this query before with lots of speculation but no actual experience of tackling this problem BUT on saily forum so trying this where some real expertise may be found.
The problem is that my main engine (30HP Tohatsu 2 stroke on a catamaran) has only done about 500 hours/6 seasons and performs well and is totally reliable so I am reluctant to replace this but it is extremely noisy at all power levels except when trickling along at very low speeds.
Maybe I should have researched this better when I bought the engine and maybe it is inherent in this type or design of engine but the noise levels I think are at an ear damaging level. Possibly a 2 stroke outboard for an hours water skiing and half an hour out to a fishing site is ok but not perhaps on a coastal sailing boat where without wind or wind on the nose it may be necessary to motor for eight or ten hours at a stretch.
I have tried lining the outboard cover with sound insulation and lining the outboard housing without any real benefit. My question is whether the sound may be transmitted through the hull rather than directly into the air in which case perhaps a new mounting system may help. What I envisage is using hard rubber (similar to conveyor belting ) at the transom clamps and top hat style rubber bushes on each side of the bolts at the transom clamp bottoms.
These bushes are not cheap and before pursuing this (quite a job to lift the engine to get at the transom) I wonder whether others have been down this road and whether there was any success in reducing noise levels. I appreciate that probably every boat is different and it may be that having a number of large flat panels is about as bad/difficult as it gets. The alternative of about £3.5k for a new 4 stroke outboard is not appealing and if the problem is the engine/hull interface could I still have a problem with excessive noise, albeit at a lower level?
The problem is that my main engine (30HP Tohatsu 2 stroke on a catamaran) has only done about 500 hours/6 seasons and performs well and is totally reliable so I am reluctant to replace this but it is extremely noisy at all power levels except when trickling along at very low speeds.
Maybe I should have researched this better when I bought the engine and maybe it is inherent in this type or design of engine but the noise levels I think are at an ear damaging level. Possibly a 2 stroke outboard for an hours water skiing and half an hour out to a fishing site is ok but not perhaps on a coastal sailing boat where without wind or wind on the nose it may be necessary to motor for eight or ten hours at a stretch.
I have tried lining the outboard cover with sound insulation and lining the outboard housing without any real benefit. My question is whether the sound may be transmitted through the hull rather than directly into the air in which case perhaps a new mounting system may help. What I envisage is using hard rubber (similar to conveyor belting ) at the transom clamps and top hat style rubber bushes on each side of the bolts at the transom clamp bottoms.
These bushes are not cheap and before pursuing this (quite a job to lift the engine to get at the transom) I wonder whether others have been down this road and whether there was any success in reducing noise levels. I appreciate that probably every boat is different and it may be that having a number of large flat panels is about as bad/difficult as it gets. The alternative of about £3.5k for a new 4 stroke outboard is not appealing and if the problem is the engine/hull interface could I still have a problem with excessive noise, albeit at a lower level?
