A new hotwell for Rainbow
Posted: Thu Nov 30, 2017 8:23 pm
During this summer's steaming in our newly acquired Rainbow (26' ex-Navy double ender), I decided we needed to add a float valve to her hotwell. Although a nice big boiler means that the water level moves slowly, I find fiddling w/ the pump bypass valve annoying. When I removed the hotwell at the end of our trip, I discovered that the drain was a piece of 1/2" pipe clumsily welded into a stainless hotwell, and that it was leaking around a large rusted area. I'd also seen salt spray drifting towards the hotwell in some wind and wave conditions, which is definitely less that optimal.
Rainbow's hotwell is approximately 7.5" square, and 24" deep - tricky for a float. In addition, there's not a lot of room to fit a more traditionally shaped hotwell w/o impinging on passenger space.
I removed the rusted steel pipe and cleaned up the rusted area, inside and out. I tried putting in a bulkhead fitting, but the wall of the hotwell was too damaged in that area for a proper seal. I tried first ox-acetylene welding the area w/ stainless rod, which didn't work well, and then brazing it a new piece, but ran into an interesting problem - the bronze caused stress cracking to appear in the stainless steel, and thus leaks. Since I don't have TIG gear, I was somewhat annoyed.... A visit to a local scrapyard turned up a slightly larger stainless tank of very similar construction - perhaps some sort of standard commercial tank, and for the princely sum of $13 I took home a new hotwell.
I installed a float valve with the long arm (12" or so) pointing straight down, added a stationary guide and connected a 6" ball float via a piece of heavy ball chain to the end of the arm, matching the recommended dimensions from the valve manufacturer. The ball chain wraps 90 degrees around the guide, and lets the float move up and down while still giving adequate leverage w/ the 12" long arm. I added a proper drain bulkhead fitting in the bottom, bolted on some angle w/ sealing washers to help retain the tank on the bottom, and made a lid from 1/8" polycarbonate. I also added a simple bulkhead fitting for the condensate to drain back into the hotwell.
I tested the hotwell w/ a hose - works like a charm. I'll install it when I'm next up in the San Juan Islands. Here are some pictures; note the shock cord securing the lid.
Rainbow's hotwell is approximately 7.5" square, and 24" deep - tricky for a float. In addition, there's not a lot of room to fit a more traditionally shaped hotwell w/o impinging on passenger space.
I removed the rusted steel pipe and cleaned up the rusted area, inside and out. I tried putting in a bulkhead fitting, but the wall of the hotwell was too damaged in that area for a proper seal. I tried first ox-acetylene welding the area w/ stainless rod, which didn't work well, and then brazing it a new piece, but ran into an interesting problem - the bronze caused stress cracking to appear in the stainless steel, and thus leaks. Since I don't have TIG gear, I was somewhat annoyed.... A visit to a local scrapyard turned up a slightly larger stainless tank of very similar construction - perhaps some sort of standard commercial tank, and for the princely sum of $13 I took home a new hotwell.
I installed a float valve with the long arm (12" or so) pointing straight down, added a stationary guide and connected a 6" ball float via a piece of heavy ball chain to the end of the arm, matching the recommended dimensions from the valve manufacturer. The ball chain wraps 90 degrees around the guide, and lets the float move up and down while still giving adequate leverage w/ the 12" long arm. I added a proper drain bulkhead fitting in the bottom, bolted on some angle w/ sealing washers to help retain the tank on the bottom, and made a lid from 1/8" polycarbonate. I also added a simple bulkhead fitting for the condensate to drain back into the hotwell.
I tested the hotwell w/ a hose - works like a charm. I'll install it when I'm next up in the San Juan Islands. Here are some pictures; note the shock cord securing the lid.