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Marine Heads

“I know this isn't a popular subject, but I have questions about the head…” stated the East Coaster closing the head door. “


“Is there a problem with it? It was just working perfectly!” I replied


“No problem, it’s fine. My questions are about the different types of marine toilets and what types of boats they are on. It’s not a great topic, but I’ll make your favorite drink if you can answer my question,” she bribed – and jingled my empty Pusser’s Rum mug in my direction.


“Ok, well, the head is a necessary evil on a yacht so it’s a valid question for me to answer:

In the days of the great sailing ships, the crew relieved themselves overboard – up forward, at the head of the ship. That’s why it’s called the ‘head’. It was a practical solution, except in heavy weather. I don't think it would be acceptable nowadays - especially here at the end of ‘D’ dock. The most fool-proof head is the cedar bucket – but it is far too gruesome for the modern yachtsmen. Thus the invention of the mechanic, manual head became popular in the early 20th century. After WWII the increased interest in yachting brought about the production of many different models of marine toilets. Unfortunately, some of the best heads ever built are no longer in production.” I explained taking a sip of my drink.


“Interesting, but there are modern heads now that are electric, what about that technology?” she asked.


“Yes, there are modern heads that have electric vacuum pumps similar to those used on RVs and aircraft. They work well on larger yachts that have an adequate supply of electricity and room for the pumps. The issue is that when the power goes down, it’s back to the cedar bucket.” I replied.


“I see. Maybe if I understood how these different types worked, then I could understand their different applications,” she stated.


“Well, if you really want to know - for the most part, marine toilets have one pump that discharges the waste out and one pump that brings water in to flush. Manual toilets incorporate the action of both pumps into one handle and one action. These types of toilets range from light-duty models that are good for day-boats and overnighters to heavy-duty models for offshore yachts. The heavy-duty types have bronze-cast pump bodies that can handle a daily duty cycle and are easy to use because they have a long lever for greater mechanical advantage. The lighter duty toilets are exactly as you would expect: lighter in weight, with plastic pump housings. They are fine for occasional use, but take greater effort to use because of the short pump stroke, but they do not stand up well with daily use and are susceptible to failure under extreme conditions.” I explained.


“I get it. You need a big heavy-duty toilet for cruising boats, a little light-weight head for day sailors that only use it occasionally. Is that why the light-weight toilet on my dad’s boat is leaking around the handle?” she asked, recalling our recent cruise.


“Exactly. Unfortunately, it is not an offshore type head and it has seen many years of hard use.


Another common problem: the smell from the holding tank treatment and that it is flushed with salt water. When salt water sits stagnant, the bacteria in the water multiply, causing a distinct smell, one that most of us could identify, even while blindfolded – like rotten eggs. This occurs all of the time, but especially when the weather is warm. Once it is there, the odor it is difficult to get rid of – flushing with fresh water is the best solution. If you are cruising and don't have the storage capacity for fresh water flushing, you can switch to salt water flushing and – when you are far enough from shore – discharge overboard, and switch back to the holding tank once you are back close to shore. I usually plumb the head sink to discharge into a pipe tee at the toilet intake through-hull valve. When you close the intake valve the toilet draws flushing water from the sink.” I further explained.


“So, you are recycling the grey water from the sink? Why not just plumb it directly to the tank or the sea cock so you can draw from either source depending on the circumstances?” She inquired.


“The recycling method works well because it conserves the fresh water supply and it provides an air gap between the domestic water system and the sanitary system. You never want a direct connection to seawater or sanitary plumbing. If a valve is mistakenly selected, seawater or waste could contaminate the domestic water and cause a very unhealthy situation. You wouldn't want to start your own black plague on the boat,” I cautioned.


“Right, I get it. I guess the sink thing works. Do you think that if we get one of these heavy-duty toilets for my dad’s boat and set it up to flush with the sink water, it will work better?” She asked


“Yes - and we should try some of the holding tank treatments that use enzymes to naturally break down the waste rather than the formaldehyde-type treatments. That would be a huge improvement.” I concluded.


“I know it’s not your trusted cedar bucket or your practical outdoor head up forward but I don't think either of those would be a hit in the crowded anchorage of the salt pond on Block Island,” she said, “Let me refresh your drink. Thanks for humoring me on an unpleasant subject.”


“Cheers!” I said, raising my glass, “I’m glad to have a conversation about the head rather than to have to fix it!”

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