Astarte Exhaust System

The cooling water comes from the heat exchanger (not visible here), up through a siphon break on the cockpit wall and down (through a flow sensor) to the exhaust riser.
The siphon break has a little drain tube to the cockpit, to ensure that any leakage will not come down on the starter or solenoid.

The exhaust riser comes up several inches and turns outward to port.  It is covered in a gray fiberglass insulation.

Where the cooling water is injected into the exhaust gases, there is a temperature sensor (like one in an cylinder head) to warn of overheating.

All fittings and hose barbs are bronze, except those into the exhaust riser, which are stainless steel to match the material of the riser.

All parts (riser, hoses, siphon break) just fit behind the nav book case and chart table.

The pot itself (Centek 2") is nestled between the engine cooling pipes and the bottom of the original piston bilge pump. 

The cockpit drain hose with two hose clamps is barely visible behind the engine exhaust hose.  It is difficult to service the seacock behind the hose.  The circular object in the foreground is a strainer for the electric bilge pump.

This photo shows the exhaust pot located to the side of the engine bell housing, in front of the aft engine mount, on a shelf at the same level as the original shelf that supports the newly replaced fresh water pump.

I had to trim the bottom flange of the pot so it would fit in this location; you can see the slanted hull coming just to the pot.

Note that the exhaust pot has a surface mounted heat sensor, to provide redundancy in the exhaust over-heat alarm system.

The exhaust hose goes up to deck level and through the bulkhead into the sail trap. It is connected to a fiberglass pipe, which nestles in next to the cockpit wall, inside the grating.  Near the end of the sail trap area, it attaches to a Centek check valve, and then goes into a hole in the lazzaret bulkhead to the through hull (with a seacock).  (The hole in the lazzaret bulkhead was made quite large years ago to accommodate stowage of oars and dinghy spars.)  (The valve and wooden cover at the bottom of the photo are part of the autopilot installation.)
With the the exhaust hose no longer going in the outside area of the sail trap, and with no muffler near the mizzen shroud bolster, there is space for a nice stowage shelf.  The big pipe in the background is the emergency tiller.