I once made tea using water from my Meaco DD8L (dessicant) and it was undrinkable. A compressor type dehumidifier (as Roger points out) is probably producing pure water.
Spraying gelcoat (or brushing) will leave a texture. It can be sanded out but very labour intensive and probably quiet skilled work. I have seen a boat ( topsides) re gelcoated and it looked almost perfect but very close inspection showed some irregularities. Also, you would want to be sure it...
Sorry just read your title - you are using a 125mm sander - I used a 150mm machine. I would recommend the larger size for such a large boat. The downside is they are heavier. Professional grade sanders of that size are about £260 but cheaper ones must be available.
I recently sanded my old coppercoat in preparation of a few coats of Gelsheild 200 and then reapplying coppercoat. I used Mirka Autonet/Abranet/Abranet Ace (in order of cost) but a finer grit - mostly 180. At that grit using a interface pad would result in minimal sanding so I reserved using it...
I bought a boat with a Thermo Top C water heater - and like yours it made lots of whirring and clicking noises but never fired up. After removing it and several years later I identified the problem as a corroded negative bus bar. Unlikely to go from working to not working in the space of 6-12...
I have two Kalori Silencio 2 5.5kw matrix heaters connected to a Thermo Top C. The heater will run for a short (20minutes) with coolant flow directed to just one matrix, with fan on full but sooner or later the thermo top will turn itself off. I think matrix heaters are rated on the basis of a...
Another way is fitting a diesel water heater - the best known are Webasto Thermo Top C, Eberspacher Hydronic or Autoterm Hydronic range. Melloronline website is a good source for typical installation diagrams.* For hot water I think most often the coolant from the heater is piped to a calorfier...
I’ve tried something similar (force a 38mm hose on to a hosetail a few mm larger) and I found it impossible - even with boiling water and heat guns. If these drains are exiting below the waterline you obviously want something very tough.