All ready for her big day.

After two test sailings, Mercer Queen in scrubbed down ready to go. The first test was to check out the new water pump and engine seals. That trip revealed two things; one that the pump worked and put water in the boiler, and two, the new seals worked so well that they revealed all of the other places that the engine leaked. These new found leaks necessitated the a complete rebuild.

So the engine went on the bench and was re-plumbed, re-sealed, etc... I also took the time to correct some curious geometry that seemed to bind it up at high pressures.

Then the last trip was on Tuesday. The engine worked like a champ. Stoking the boiler on the other hand was quite a challenge. We just couldn't seem to build and hold pressure. It was then that the Earl noticed the valve for the stack venturi was open, and when he went to close it he broke the valve. It was a pretty heavy duty gate valve and the cover for the gate housing sheered off as he tightened it down. That left us dead in the water 300 yds downwind of the launch. I had to hand crank the paddles all the way back.

But now the valve is replaced and everything is set to go. Most of you will know about the christening this Saturday, but for those of you who don't and might like to show up, here's the invite. It should be quite the do, with rides to follow. See you all there and then!

Engine Update

As I said in my last post, the engine is up on the bench for some much needed repairs and upgrades. The first order of business was to fix the pulled out cylinder post. No big deal there, just some drilling and tapping for the bolt and backing plate (essentially a big washer). With that done, it was on to the water pump.

The pump you can see in the bottom left of the picture to the left. It's that long brass thing. Its a positive displacement gear pump, which should mean that no matter the speed, it will still pump water, and put some pressure on it as well. That's the theory anyway. In actual practice it needs to be going around a bit faster than once a second, which is the engine's approximate speed. But how fast?

To figure it out, I took it off and hooked it up to an electric drill, then put a gauge on the outlet end and had it pump water. To get a consistent 30 lbs took about 600 rpm, or ten times around in a second. That was the limit to the gauge I had on hand. Needing 40+ lbs I figured 900 rpm would be more than enough to overcome the pressure and pump water into the boiler. So I built a gearbox out of some sprockets and chain I had around. The result is what you see in the pics.

For those of a mechanical bent, The ratios are 2.4:1, 2.5:1, and 2.5:1 for each linkage giving a total ratio of 15:1. So for each time the main shaft turns, the pump shaft turns 15 times.

The pic on the right is the back side of the gearing and you can see the three linkages. The sprockets on opposite sides of the mounting block are connected to a joining shaft and turn on center together.

There's quite a bit of mechanical loss in doing it this way, but it was quick and relatively easy. I would have preferred to use spur gears, but that would have been a lot more machining than I have time for at present. Perhaps for the new engine.