ST21 'Skinnydip' build, and boating adventures, Noosa, Australia

[Fuzz]

I sure hope the fears over the AO not being an grand slam event never come true no matter how much money other countries might throw at their own events. It would just not be the same. It would be like buying Wimbledon and moving it to the middle east.
I too hope Barty wins this year because of how she acts. It would be nice if your top male would learn from her.

[glossieblack]

Thanks Fuzz. Nicely put.

Yesterday I removed the cast iron wet exhaust mixing elbow from Great Sandy’s Volvo Penta diesel engine, and soaked it overnight in a diluted hydrochloric acid to remove internal carbonisation and internal rusted cast iron.

The acid bath removed enough of the carbonisation to allow me to prod around the internals of the mixture with a narrow screwdriver, and with a little force it pierced through to the outside of the mixer. The conventional wisdom is that in warm ocean waters, the mixers should be replaced after five years, so this no great surprise.

The first pic is of the new mixer, the second shows the exhaust gas and seawater inputs from the engine (the larger exhaust gas one and the smaller cold seawater one), and the third the output to the wet exhaust (the inner tube delivers the seawater). The last pic shows where the side wall of the mixer has failed after probing from the inside with a screwdriver.

The failure is right where the hot exhaust gasses mix with the cold sea water to form a highly corrosive mix.

I doubt it would have survived another cruising season without failing at sea, with consequent threat to human life (carbon monoxide) and engine life (overheating).

[OrangeQuest]

Seems that part could be cast with a high heat plastic that would resist the corrosion better and longer. Then they could charge even more for it!!

[glossieblack]

It's been a beautiful sunny day on the water in Noosa today, so I've mucked around on Great Sandy doing a few odd jobs and installing the new mixing eblow.

I'll touch-up the attachment bolts and hose clamps with Volvo green paint in due course.

[Eric1]

Nice job Glossie.

[Jeff]

Nice work GB!!!! Jeff

[glossieblack]

I hurt my head today, to no avail.

These past four months I've resisted reflecting on why Skinnydip's 20 hp diesel engine destroyed three difference damper plates of a 1:1 ZF Hurth hydraulic trannie rated to 300 hp, but comfortably co-exists with a Twin Disc 1.5:1 mechanical trannie rated to around 50hp.

I've been quietly confident the answer would just pop up from my subconscious sooner or later, given the amount of time I'd spent thinking it through over previous years of frustration. But nothing even vaguely popped.

So today I thought about it long and hard. Still nothing. :roll.

[OrangeQuest]

I will admit, I gave it a lot of thought as it was happening and after. I know everything possible has been tested, checked and measured. But without touching it the only thing it seems can cause such a strong dampener to destroy itself in such a short time with so much under power compared to what it is rated for is alignment between engine block and transmission. Which I understand that was checked many times. Anyway, I gave up on figuring it out over the web a few months ago.

[Jaysen]

Is it possible that there just wasn’t enough pressure between them? Ex the alignment was good but the bell housing needed faced by a couple thousandths?

Not that it matters now. Just the one thing I don’t recall being mentioned.

[Spokaloo]

Has the opportunity presented itself To get some performance data on the boat? All up weight, speeds at each 200rpm increment, estimated draft at each 500rpm increment?

Still hoping for some good data, some good video, and an understanding of what the performance means to you.

E