Sight Glass on the Trevithick Boiler
by John
Not real happy about this one, but it is necessary if I am to run the dredger engine in public, at club meetings etc.
The original dredger engine had 3 taps to check on the boiler water levels, like this.

An earlier stage of construction, using taps to reveal the boiler water level.
Unfortunately that setup is unacceptable for boiler certification, so I have installed a sight glass using the same penetrations.

The red colour does not help. But when I run the engine on steam, this is what will be seen. Functional, but nothing like the original. If I use compressed air, or steam from an outside boiler (i.e. my burner not being used), I can reinstall the taps.
The sight glass is a bit short, but it should comply with the regulations.
I have spent another half day experimenting with different spring configurations, so that the safety valve releases at 40-50psi. Eventually I decreased the coil pitch of the spring, and the valve now releases at 45-50psi. That will do.