Well, as we reach March 2024, I should jot down some notes on the work being undertaken this winter.

Work done

We made a list of jobs to be done back when we fetched Befur out last autumn. The completed work is shown below in Green, still to be done in Red:

1. Cleaning the inside of the boiler, removing oil t0 improve efficiency (reduce fuel consumption) – Done – notes and video here
2. Cleaning the inside of the condenser, for same reasons and improve vacuum – Done – notes with Boiler Work above.
3. Remachining the LP crosshead and glands as it is now clear that this is the principal source of the hateful knocking the engine makes. – LP Done – see below
4. Replacing the pump drive worm box, as this is at the point of failure, and adding “assistance springs” to reduce the torque requirements on this box, to extend its probable life! (probably another post here too). – See below
5. Replumbing the condenser to be “contraflow” as this should improve it’s efficiency too.
6. Attempting to design and fit a clutch to the prop drive to allow it to freewheel when sailing.
7. Attention to paint and varnish
8. Possibly fitting a reinforcing  inner fore-deck and removing the anchor chocks and resealing to improve weatherproofing.

Pump Drive Work

At the end of last season I noticed a lot of slop/looseness/lost motion in the pump drive ( the engine could turn about 15-degrees without the pumps moving). I thought this was the worm box failing. The drive to the pumps was also a considerable source of noise when running.

So we undertook a major overhaul/redesign of the drives. In the end we concluded that the worm box was OK, but I fitted replacement (as I had ordered one to be ready), the slop was mostly caused by worn keys in the drive to, and output from, the worm box.

So, the work completed was:

1. Narrowing the whole assembly by about 5mm to get the outer bearing fully located over the crank stub.
2. Fitting better spaces and shims to hold shafts in axial alignment
3. Replacing the drive support bearings on the crank (I had fitted “shielded” instead of “sealed” bearings and one of these was in severe distress (noisy and worn).
4. Making and fitting better (tighter) fitting keys
5. Improving duplex chain alignment.
6. Encasing the chain drive to help with cleanliness (of the chain and boat!!) and reduce noise. (attaching this with M3 screws into the edges of 5mm gearbox plated, required a jig and some care to drill and tap!!!)
7. Fitting “assistance springs” to the pump rods. These are compressed on the pump return stroke and then reduce the force required on the pump stroke, to make the worm-box’s loadings more even and lighter. (this required a lot of computing and thinking, with help from Roger Calvert and Chris Davies).
   

   Pump drive after narrowing, but before enclosure and assistance springs

   

   Calculating Pump Torque

   It seemed quieter when testing on the lathe…. as this video below suggests. The net effect was to reduce the peak torque from about 11.5Nm to about 6.2Nm (on the return stroke) and about 5Nm on the pump stroke – about a 50% reduction in loading. An interesting bit of work based on a paper from an Australian University (thank god for Google!!).

Silencing the Engine

We then turned to improving the fits on the engine. We knew the LP crosshead clearances were too big (~8-10-thou), and the reason for much of the knocking when in operation.

So a lot of measuring (calipers, dial gauges, micrometer etc.) showed that the slideway keeps were the problem. These were adjusted on the shaper (good for angled/tapered cuts) and then a lot of hand scraping, stoning and repeated reassembly! The net effect of that was an engine that was (somewhat) quieter – but not perfect yet…

Video of finished Engine Running On Air

Next Steps

1. We will try to find the remaining slop causing the knock. This appears to be at BDC on the HP cylinder (running the video slowly to see the relationship between knock and pictures). On inspection one of the lubricating pumps had become stuck (the HP crosshead and piston rod bearing one), so I suspect that is where the problem lies.
2. Remove, wash (in a washing machine) all the rigging from the boat – it’s gone green and stiff, and a test wash of the Mast Lift showed this was a good solution – we are going to be very careful, as it took some time to get the rigging right and properly laced, and we don’t want to go through that process again.
3. Make and fit a new fore-deck (under the existing delaminated existing one!!!!).
4. Weld up and replace the trailer mudguard that lost a battle with the gateposts at Ferry Nab (a real test of my TIG ally welding! )
5. Try to design, build and fit a dog-clutch to the drive shaft to allow the prop to freewheel when sailing.
6. Clean out the bilges!
7. Fit new hand pump (having nickel plated it first!
8. Reinstall the boiler, engine etc.
9. See if it’s all any better.

Steamboating surely stops you getting bored and wondering what to do with your time!