Joints and hose clamps
Never rely on a flexible joint to support any exhaust component, unless it is a very short run of lightweight GRP tube. The joint will eventually sag under the strain, possible breaking the seal between the hose and the Component, causing a leak. And the misalignment will increase back-pressure and reduce efficiency.

Every joint between flexible exhaust hose and a rigid component should be secured with two stainless steel clamps to ensure adequate contact area between the hose and the tube. The effort sometimes needed to 'persuade' exhaust hose over solid pipework can lead you to think that it would never come apart again, but given time, movement and vibration can cause hose to just slide off the tube if it isn't properly secured in the first place.

Ordinary worm drive clamps which use a perforated strip and screw adjuster (rack and pinion principle) are not normally man enough to compress extremely tough exhaust hose. Proper exhaust clamps use a nut and bolt system able to provide much higher clamping pressures, but must never be over-tightened.

Silencers
Silencers must be securely mounted and properly supported -the flexible joint should not carry any weight. The best way to mount inline mufflers is with a saddle type bracket that keeps the silencer body clear of the hull or other structure. Stainless worm-drive clips are fine for securing the silencer to the bracket, as the pressure required is only moderate. Your exhaust supplier should be able to supply kits to make up worm-drive clips to any length you require. Don't forget the 7-degree rule.

Vertical lift silencers normally have a square mounting plate at the bottom which should be bolted or very firmly screwed to a suitable base. It is well worth inserting a section of sound proofing between the silencer and the base support, using bolts and nylon locknuts to allow a tiny amount of movement. This can noticeably reduce vibration and prevent noise being transmitted into the structure.

if the position of the silencer makes the drain plug awkward to get at, screw a hose adapter into the silencer body and remotely mount a drain tap in a convenient location. You will be pleased you took the trouble at the end of the season.

Outlets
Hull outlets should ideally be mounted at least half a diameter above the static waterline and protected with a flap. If your outlet is close to, or on the waterline, it is good practice to have a steeply rising section of exhaust pipe as close to the outlet as possible (See the low engine mounting diagram in Chapter 2 for an example.) A gooseneck fitting attached directly to the hull outlet achieves this nicely.

Installation Tips