Skip to main content

Gravity Theory

Smell. Pong. Effluvium. Whichever way you describe it, the airborne essence emanating from Ostara’s aged sanitation system was highly unpleasant. More than just an odor but thankfully short of a full-blown stench, it permeated the forepeak and almost caused a spousal mutiny during our first weekend aboard. No doubt about it – something had to be done.The sanitation system comprised a

Smell. Pong. Effluvium. Whichever way you describe it, the airborne essence emanating from Ostara’s aged sanitation system was highly unpleasant. More than just an odor but thankfully short of a full-blown stench, it permeated the forepeak and almost caused a spousal mutiny during our first weekend aboard. No doubt about it – something had to be done.

The sanitation system comprised a Wilcox-Crittenden toilet connected to a Vetus bladder-style holding tank under the V-berth. The toilet pumped out via a 3-way diverter valve, which directed waste either into the holding tank or out to sea. A dedicated pump to empty the holding tank was connected to the diverter valve via a T-piece. The diverter valve and the pump were under the bunk in the forecabin along with the flexible bladder holding tank.

The holding tank did not have a vent. It had a long outlet hose going through the bulkhead into the anchor locker and up to a waste pump-out fitting on the foredeck. The outlet hose leading to the outlet seacock had a vented loop well above the waterline. There was no anti-siphon provision in the inlet hose; its entire run was below the waterline, risking water flooding the boat via the toilet bowl if the lever was left in the wrong position and the inlet seacock was open.

All in all, this was a most unsatisfactory system. Not only was it needlessly complicated and awkward to use, there were too many connections with the potential to leak and cause odor, and waste tended to sit in the long runs of pipe (as I discovered when I was removing the old hoses from the boat). The bladder tank under the V-berth was poorly secured, unvented, and smelly. With no breather, it would have been all too easy to overfill the tank to bursting point. Enough said.

So, after consultation with a couple of friends who’d done the same thing, I decided to replace the holding tank with a gravity drain system. This is simplicity itself. All you have to do is mount the holding tank so that its bottom is above the waterline when the boat is at rest, and its top is above the waterline at the maximum angle of heel. The toilet pumps directly into the tank, and the tank drain directly to the outlet seacock. To empty the tank, you just open the seacock, and gravity takes care of the rest. As an added benefit, the motion of the boat through the water will force seawater up through the outlet hose and into the tank, thereby rinsing it out. With the seacock closed, you’ve got a legal Type III MSD if you have also plumbed a deck pump-out fitting into the outlet hose.

There is no need for a vented loop on the outlet hose, because the vented tank acts as a siphon break. The inlet hose should be looped above the waterline and, depending on the toilet you use, fitted with a vented loop. A breather hose also must be plumbed into the top of the tank.

I’ve had to unclog blocked heads a couple of times too many; going over the side with a wire coat hanger to ream out the outlet pipe or stripping the pump to remove a wad of toilet paper gets old pretty quickly. That’s why I decided to junk the veteran Wilcox-Crittenden with its faithless joker valve and treat the boat to a Lavac. This British-made toilet has no moving parts. It operates on a vacuum principle that, not to put too fine a point on it, macerates the contents of the bowl to the point where there’s nothing big enough to get stuck anywhere. I’ve never heard of one clogging up, plus the Lavac is extremely frugal with flushing water – a mere 3 pints per flush – which make your holding tank go further. This is vital when you’re cruising with the family. It’s pricier than the Par/Jabsco budget toilet but cheaper than the upscale thrones from Raritan and Groco. Anyway, what price peace of mind?

Related

Ulysse Nardin promo photo

The Ocean Race Names Official Timekeeper

With just under one year before the start of The 2022-23 Ocean Race, Swiss watch manufacturer Ulysse Nardin has been named the official timekeeper of the race. The Ocean Race, formerly known as the Volvo Ocean Race and before that the Whitbread Round the World Race, announced ...read more

Arthur Daniel_RORC Maserati - RORC Transatlantic 2022 - Jan 15th -Social Media-4

Fast Finishes for the RORC Leaders

Over the weekend, the first finishers of the 2022 RORC Transat made landfall in Grenada, led by Giovanni Soldini’s Multi70 Maserati, which was awarded line honors with a corrected time of six days, 18 hours and 51 minutes. Maserati finished ahead of Peter Cunningham’s MOD70 ...read more

Background-02

Notice to Mariners: A Blog from the SAIL Editors

As a teenager, I stumbled across a copy of Derek Lundy’s Godforsaken Sea in the back room of a used bookshop. I had never heard of the Vendée Globe and frankly found all the boat-speak in the first 50 pages a little difficult to get through. But Lundy’s storytelling and the draw ...read more

Screen-Shot-2022-01-13-at-9.26.59-AM2048x

VIDEO: Celestial Navigation Episode 2

Celestial navigation is an invaluable tool for all kinds of sailors. In episode two of the celestial navigation series, learn the basic elements of navigation and the sight reduction process using declination and GHA to determine the Geographic Position and navigate using a ...read more

Film-poster

Cruising: Year of the Sea Shanty

Along with other timeless pursuits, like baking sourdough and gardening, singing sea shanties surged back into popularity during the recent lockdown, thanks, in part, to the app TikTok and its “duet” feature, which allows singers from around the world create music together. By ...read more

Book-Cover-9780712353700

Book Review: Sailor Song

Sailor Song is the ultimate guide to the music of working sailors during the 18th and 19th centuries. The book includes lyrics and sheet music for 50 of the most beloved sea songs with fascinating historical background on the adjoining page. Chapter introductions provide ...read more

Screen Shot 2022-01-12 at 10.42.33 AM

Race Update: RORC Transat

With the fleet leaders about halfway to Grenada, the 2022 RORC Transatlantic is shaking out to be a tactically interesting one. The race, now in its 8th edition, began on Saturday with 30 teams ranging from 70-foot catamarans to a 28-foot JPK 1010. Early in the race, light winds ...read more

01-LEAD-IMG_1585

Experience: Fire Down Below

Due to the Covid-19 pandemic, local racing had resumed with household crews only. My wife, though, while always up for a pleasure sail, was not up for this kind of thing, so, for the fifth time in what was any measure an unusual sailing season, I found myself singlehanding my ...read more