It still is a crude set-up, but I have the first prototype of a working feedwater preheater/condenser.


The feedwater, instead of at ambient temperature, now enters the boiler pretty hot (how hot I can't tell on account of the calibration certificate of my fingertips having expired, but I can't touch the feedline, near instant retraction reflex, meaning probably around 80 deg C (176F) or better, and it seems I am getting a fair bit of condensate in return.

I still have to do something about the steam outlet, because as it is right now, al that vapour in the boat sooner or later will cause problems with the wooden parts getting wet and distorting.
I also hope to be able to improve on the amount of condensate return.


EDIT: first (fairly crude) measurements appear to confirm a reduction in fuel consumption of about 10% (which has zero economical purpose, but the extension of operating time is always welcome) and the feedwater supply tank now suffices for 35+ minutes, while it used to be 25 tops.

But every upside has a downside, and I need to revise the piping a bit, because now there also is a lot of unwanted condensation in the boat. Mainly because where previously all steam was vented off at fairly high velocity, blowing all droplets present in the exhaust steam well clear of the boat, but now less steam is vented at a lower velocity, causing large droplets to fall back into the boat.