The new engine uses a 2" exhaust outlet as opposed to the old 1 3/4" exhaust. After deliberating about over pressure issues I decided to replace the whole exhaust system from the engine to the transom.
The new 45 degree exhaust elbow.
This gate valve is the last one on the boat.
An end on view of the exhaust port.
The exhaust hole is actually an ellipse. Mounting the flange presents a bit of a problem.
I don't think the new flange will cover the entire hole. Also there isn't adequate steel for securing it.
I cut the gooseneck off. Note the structural beam near the back that goes over the tail pipe. Because of this I think it is best to leave the exterior alone and work things from the inside.
I got down in the lazarette with a monkey wrench to remove the valve body. The pipe appears to be in fine condition.
The gooseneck is to keep seawater from following seas from backing up in the exhaust to the engine. It's going to fit on in the position shown here. I could just fit a short length of exhaust hose on with clamps but the pipe is a bit smaller than the goose neck fitting. The hose is wire reinforced so I'm not sure the hose clamp will hold it down sufficiently. I could build up the outside of the pipe slightly with high temperature epoxy. I have queries out on varous forums and product support to find out.
The Metal Boat Society www.metalboatsociety.org provided a solution that I think will work. Thanks Terry. I started by cleaning the threads and first 1 1/2" of the tail pipe. It is indeed stainless.
Next I wrapped self curing tape on the cleaned pipe.
I set o rings in place to make hose barbs.
I taped over the o rings to complete the hose barbs.
It made a nice snug fit. I used torque bolt clamps to secure it in place. As you can see I really had to torque it down to fit on the gooseneck even though the hose and the gooseneck were both nominally 2 inches.
Here is the two stage muffler I decided on. It is a Vetus NLP50S. It is supposed to hold a lot of water that runs back from the hose when the engine stops.
It is to sit on this little platform that I made of marine grade plywood and epoxy sealed.
Here it is all hooked up.
The hose to the engine hooked up. During the first run I had to tighten several parts of the muffler and hose connections.