Over propped?

[rickinnj]

About 10 DPM.

[rickinnj]

no good deed goes unpunished

The last time I left you I had achieved 4.7 kts SOG both directions along the fairway in the marina @ 1250rpm.

I decided to replace the exhaust since the hose was original and soft. I thought maybe there might be some performance to be gained from some long overdue maintenance. And I figured I might as well pull out everything and do some cleanup...bad move...sorta.

The black iron is rusted from the outside.

What I've always thought was a standpipe is actually some sort of heat exchanger. The exhaust is completely isolated from the raw water side.

I'm not sure if I'm gonna be able to separate the black iron from the standpipe without causing damage. I might have to scrap the entire setup and go with a riser and water lift.

[joe_db]

Yikes! What IS that thing

[Surcouf]

Yikes! What IS that thing

something pretty dead... Happy corrosion day!

[ndutton]

What you're calling a standpipe now is more accurately an abbreviated water jacketed exhaust and you may have a bigger problem than the rusty pipe going into it. Why so rusty? That area of the exhaust is designed to be bone dry inside and out so where did the water come from to cause the extensive rust? Its proximity to the water jacket and directly below it suggests the water jacket is the source. If it is, it shouldn't be so something is leaking there.

[rickinnj]

first the cockpit scuppers were leaking when I bought the boat, fixed.

next, there was a shaft packing leak, fixed.

then the raw water nipple on the outlet of the exhaust manifold sprung a leak, fixed.

In each case, I neglected to remove the heat wrap. Yesterday I did, and chunks of pipe peeled off with the wrap.

the "jacketed exhaust" does not leak.

[ndutton]

If it were my boat (it's not), I'd pressure test the water jacket component of the exhaust just to be certain. It's a simple test with no downside.

[rickinnj]

last night, I clamped shut the top water hose and used my bicycle pump to establish approx. 5#. I held it there till I got bored with it with no leak down.

I'm swinging by the local big box store this afternoon after work to check on availability of 1 1/4" black iron piping components to build a new hot section.

I don't have room under the cockpit for Moyer's pre-built hot section. As you see in the first photo, I'll need to swing the hot section over to the lazarette for height clearance.

[joe_db]

I don't get the point of that thing. All it does is cool the exhaust, which happens anyway downstream at the water injection point. A piece of straight pipe well wrapped could be there instead.
You could make a water or cabin heater circuit with it, but other than that I don't understand the purpose.

[rickinnj]

if nothing else it provided a riser for the exhaust. I don't know...maybe they had it sitting around the yard in Niagra on the Lake. they were blazing new trails on hull#1.

[rickinnj]

ordered the first piece of the new exhaust. This should get me out from under the cockpit deck and into the lazarette. From there it's a 6 foot straight shot back to the transom.