This post continues/concludes the story of manufacturing a new crank for Befur from the last post.
Here we can see the re-assembled engine with new crank. We are still to install all the ancillaries (reversing gear, lubrication, condenser and feed/air pump & alternator drive.)
It took 6-man days from receiving the crank back from the grinders to reach this stage.
Once we have tested it on air, we will reinstall it on the boat and undertake this year’s boiler test and check all is as it should be.
Machining Crank Pins
Those of you who have been following Befur’s progress will know that our first year in the water was marred by the failure of the crankshaft in the Leak Compound engine I built.
This post deals with the manufacture of a replacement, and the results of my research/experience into the approaches to building cranks for “small” (<20HP) marine steam plants.
Methods of Manufacture
Well, I have been very quiet over the last few months, but some work has progressed. As I noted in October, we had a quite extensive list of snagging to address, not least the crankshaft re-manufacture…. well, while quiet on line, I have made some progress in the background, so I figured an update is in order: Continue reading
Well we got Befur’s engine back into the workshop, and stripped it down to see if we could locate the source of the knocking we have been suffering all season.
Befur’s Engine ready to be stripped.
On lifting the crank out it looked perfect, and did not have any obvious loose or moving joints My heart sank, as this was really my only theory on what was wrong. Continue reading
Just a note to say that Befur is out on the hard now, so we can commence the over-winter work.
We made about 5 or 6 trips on the lake in the season, and spend quite a few days on the mooring spannering the various issues we had into submission.
However, just before we fetched her out the first named Storm of the year “Ali” produced some impressive weather, with gusts of over 70mph on Ullswater. We stopped by to see how she was doing on her mooring – here is a video…
The main task is to find the source of all the knocking and rumbling (which I still think is most likely a fractured crank) and then tackle some other outstanding issues. This list is to remind me what is to be done:
- Inspect/fix/remake the Crank
- Cure the leaks between HP cylinder and Valve Chest
- Make some Gauge Cocks (to damp the pressure surges in the gauges)
- Tidy up the fittings for the stern-tube cooling feed
- Re-paint antifouling (as quite a lot fell off!)
- Inspect/test all the vacuum side for leaks as it’s still quite low (~10-15 inches hg)
- Make a new ball-cock valve for hotwell (plug-cock type)
- Maybe make some drawers for the galley
- Fit a stern light
- Think about remaking the cockpit sole to improve access to stern-gland etc.
- Fit a seacock to the blow-down line (to allow the flexible hose to be removed when afloat)
- Install a skin-fitting for the bilge ejector…
- Make a whistle that whistles!
- Attend a VHF course, to get my license 🙂
Yesterday I stripped down the plant ready to have the engine lifted out next week. I also took some pictures to remind us how it all goes back together!
Well, as we approach the end of the 2018 season, we have decided to fetch Befur back onto dry land a little earlier than planned. This is principally because I can’t tolerate the racket the machinery is making underway, and it seems cruel to run it further pending the noise turning into a real “issue”.
…and it floats level!
We did have a nice steam this week about 2 1/2 hrs round the northern reach of the lake in a “fresh” breeze. We were towing the inflatable (still nervous about our reliability) and this very nearly became airborne as we opened Befur up into the headwind – she goes quite well. Continue reading
As Lou explained (as I sat in the land-rover feeling quite defeated) “It’s like when you built the racing bikes/cars – you can’t expect to show up at the circuit and have it all work perfectly the first time you race it. There is always going to be development work.”
…and I guess she is right!
This post firstly relates the trips we have made so far, and secondly attempts to provide a balanced view of the successes and failures to date – to help other builders.
Trials (and tribulations)