Collecting rain water on deck
Atom's Deck Rain Water Collection System
When cruising you don't always have easy access to unlimited fresh water. Collecting rain water is a cheap and low maintenance alternative to a watermaker. Even if you don't want or need to use it for drinking, you can certainly use it for washing and showers.
Aboard Atom I use option 1 in the sketch above. The starboard side plumbing is led forward through the cockpit locker bulkhead so the ball valve handles and 6' length of outlet hose is accessed through the galley dish locker. The port side is accessed through the locker that used to be the icebox. Option 2 in the sketch might be better if you found the right size Y-valve. An outlet hose that easily slipped or snapped on the ball valve or Y-valve outlet and didn't leak might be an improvement so you don't need to store the hose coiled up in the dish locker. In practice, after the rain clears the deck of salt and dirt, I close the drain valve, uncoil the outlet hose from the locker and put the end in a bucket or jug on the salon sole and open the other valve. I taste the water for salt and if good, pour the bucket into a funnel with strainer into the forward water tank or fill extra jugs. Meanwhile the hose is filling another bucket. If rain is scarce and water supplies low, I save the first slightly salty or dirty water for washing clothes or fill the solar shower. Normally you can't fill directly from the hose to the water tank because it requires a long hose that doesn't flow well and at sea you never know when a wave will come aboard and instantly turn your water salty. As long as you fill one container at a time you can easily dump the contaminated water and start over once the deck clears again. Don't forget to return the valves to deck drain position when finished unless you want the decks to drain into your lockers! Before this I tried putting a cork in the original scupper and opening a single ball valve connected to a thru-deck drain installed forward of the scupper in the galley dish locker area. This is much simpler and leaves the original scupper plumbing undisturbed, but I found the thru-deck fitting and hose were always plugged with debris and I didn't like having to go out in the rain to cork and uncork the scuppers. Boats other than the Triton can adapt the plumbing to suit their scupper layout. Ideally, the scupper would be located in an area accessible from the cabin so that you can simplify the plumbing by adding a Y-valve or Tee fitting directly in line with the drain hose. Of course, the scupper is located in the lowest part of the deck for effective drainage and can't be moved. Usually, the constant draining of water through the system keeps the hoses clear, but once every year or two you may need to disassemble some of the fittings to clean out the debris that collects inside. I also tried collecting from the mainsail and bimini with less success because of the limited collection area and need to go on deck. When running downwind, if you don't mind standing in the rain and carrying buckets along the deck, you can ease the mainsheet, pull up the boom topping lift, and hang a bucket under the gooseneck. In port you can rig an awning to collect the rainwater, but it seems it is never set up at the right moment and you need a system to stop wind from spilling the water away from the drain area. An awning has the advantage of normally being cleaner than the deck, but it can't be used at sea. The deck system is always ready to go without setting anything up or taking it down. You would think rain water is pure, but either from microbes or something in the atmosphere or on the deck, after a few days the stored rainwater usually starts to grow moldy so I immediately put in a teaspoon of bleach for each ten gallons and that keeps it clean.
Please contact me if you have questions or want to share ideas for an improved system.