Installing the new waterlock

I am replacing Wing's wet exhaust system: the old exhaust used 1 3/4" hose while the new Beta 14 requires 2" hose and the old setup would also not allow for the correct vertical clearances for the new engine.  The first step is to install the new waterlock.  I have chosen to use a Vetus Marine NLP50; it is the only waterlock available locally that will fit in the limited space behind the engine and provide the required 12" vertical clearance between it and the wet exhaust manifold water injection point.

The waterlock needs to sit as far back as possible and this is one of the main reasons for choosing the NLP50; it is narrow and the upper chamber can be rotated relative to the lower in order to get it very close to a bulkhead.  The furthest back it can go will be on a platform I will install on top of the two aftmost floor timbers beside the prop shaft shown below.

 

I have made the platform out of an old piece of meranti marine plywood I had lying around from a previous project.  Here it is dry-fitted to the floor timbers.

The forward end of the platform is screwed directly to the top of the forward floor timber while the aft end sits on a supporting block I attached to the forward face of the aft timber as shown below (the supporting block is already painted in this photo).

I gave all of the wooden components two coats of Interlux Pre-Kote Plus followed by two coats of grey Bilgekote.  I then thru-bolted the waterlock to the platform using four stainless steel machine bolts and screwed the platform in place.  Here is the completed installation.

 

The ability to rotate the upper chamber allowed me to get the waterlock very close to the partial bulkhead behind it.  In this position the waterlock is almost exactly 12" behind and 12" below the expected location of the wet exhaust water injection point - the minimums specified by Beta Marine.  None of the other waterlocks I mocked up gave sufficient clearances so the NLP50 was the only option.

I now need to remove the old 1 3/4" thru-hull from Wing's transom and replace it with the new 2" one.  This will require some cutting and will be the subject of another post.