The Desiccating Head

rev. 7-24-2024

Three years later I'm still thrilled with this for a daysailor and even for weekend cruising on a small boat. Basically, anytime the alternative is a port-a-john.  

• Less odor. Practically none if properly managed.
• Lighter by 2-3 times.
• Easier to service. No lugging the whole thing off the boat. Just bag it and toss.
• No winterizing.

 I built mine largely from fiberglass, because I had the tanks handy for free, but plywood could be very good if well caulked and then well-painted. It really does not get messy in there.

 

 My Stiletto 27 had a portable toilet that stunk. Use the right chemical and it stinks less. Every time it is used a laborious haul/dump/clean process is triggered.

My PDQ 32/34 had a nice holding tank system that I had engineered to perfection. No odor, nearly like home. But it required space and weighed a good bit. Perfect for the PDQ, but totally unsuitable for the F-24.

We really only day sail the F-24 trimaran, and the head is only for emergencies. It didn't get used for years at a time, so we switched to WAG bags. Never used them.

 I'd been poo-hooing composting toilets for years. I'd experienced some nasty ones in cabins and some friends had a bad experience with a Natures Head. In fact, both failures probably included elements of design and operator error.

I was asked to investigate the topic, and so I did. There was a long-winded article in Practical Sailor last month, covering both toilet design, absorbents, and anti-odor additives for the urine tank.

 There are two keys to function:

• Separate the urine from the solids. First, the smell is greatly reduced, and second, the solids side it much drier, preventing it from getting wet and aerobic.
• Dry the solids. Like any animal dropping, once it is dry on the outside, there is little odor. That is the function of the absorbent; to speed drying, filter the air, and cover. It is NOT to cause composting. This is a desiccating toilet. 

There simply is not room on a boat for true composting toilet. The process tanks months, requires temperature and moisture control, and continuous mixing and ventilation.  Since you cannot effectively compost, then stop pretending and dry the waste instead. You can then take it home and compost it if you like, or double bag it and dispose of it like litter box scoopings. Your choice. The urine is odor-free once treated (see below) and can be disposed of easily.

I built a test version from a storage tub, a bucket and scraps to test the absorbents and additives. It was a crude thing, but in fact I used it in the basement bathroom for two months, during which it proved to be amazingly odor-free and easily to deal with. I was stunned. It was time to eat a large helping of crow. But I was happy to eat the crow, because the result was a truly user friendly head solution for my F-24.

 

 

The final version was based on molded parts from Separatte, a fiberglass tank I modified to fit the available space, an under seat baffle I cut from fiberglass, and yes, a bucket and jug. The top hinges up for service, which is a simple matter of lifting out a bag and replacing it; a clean, contact-free process. The absorbent of choice, at any price (I tested many), is millwork sawdust and shavings I get for free (aspen bet bedding is also very good). The urine treatment is citric acid, though vinegar and Nilodor are also very good.

I no longer see any point in conventional portable toilets, at all. A desiccating toilet is better in every way. Regrettably, you must either pay a king's ransom or build your own.

Human Powered--What Does COLREGS Say?

 Nothing too specific. But in Coast Guard Nav Rules FAQ post the following is offered:

13. Where do Kayaks and Canoes fit into the Navigation Rules? Kayaks and Canoes are a vessel under oars and are addressed specifically in Rule 25 (lights)
 
Although a vessel under oars may be lit as a sailing vessel, one should not infer that they are considered to be a sailing vessel for other Rules (i.e. Rule 9, 10, 12, 18 or 35). Ultimately, the issue of whether a vessel under oars is the give way or stand-on vessel would fall to what would be required by the ordinary practice of seamen, or by the special circumstances of the case (Rule 2), and, the notion that they are less able than most other vessels.
 
Per Rule 25(d) they must be lit with 1 of 3 options between sunset and sunrise:

1. display the lights of a sailing vessel (per Rule 25 and Annex I); or
2. display an all-round white light (visible for at least 2 miles [per Rule 22] and meet the technical characteristics [i.e. color, intensity] per Annex I); or
3. have at hand either an electric torch (flashlight) or lighted lantern (oil or gas) which need not comply with Rule 22 or Annex I.
   • Preferably, option #3 provides similar lighting, intensity and characteristics of an all-around white light (versus a single beam of light);
   • may be mounted, worn, stowed, etc so long as it is ready at hand to warn other mariners; and,
   • should be used in ample time so as to warn others of danger and in manner consistent with Rule 36, so that it not embarrass any vessel (i.e. so as not to blind or otherwise negatively impact their navigation).  See FAQ#14 (below) for a discussion regarding high intensity and flashing lights.

I'm rather puzzled at why the original means of power did not rate definition and specific discussion. Yes, some of this is obvious, but still. Why not spell it out? Sure it varies a lot. Perhaps it is because the maneuverability of a kayak compared to a cruising boat with a sculling oar are very different, bu the same could be said of a Sunfish vs. a tall ship.