Hello! Newbie here. My husband is building a one-of-a-kind houseboat, plans designed and fully drawn-up somewhere in his backbrain. He's currently building 8'lx4'h trapezoidal pontoon sections (and bolting them together in tandem in the water; eight down, six to go) for what will be a 56' plywood-hulled catamaran, with house on top and outboard motor aft. It has fallen to me to design the interior, and the question of sanitation has arisen. So, what do y'all think of composting toilets? Any favorite brands or warnings? Our cruising, at least at first, will be along the East Coast, ICW, rivers and bays. I gather, from reading another thread here, that gray water discharge in these waters is ok. Also I'm wonder about hot water, solar or otherwise.

Thanks much for any advice!

Amelia

(here's the progress report http://reiheld.home.mchsi.com/boat.htm/

HI Amelia...welcome aboard! I moved your post to start a new thread (see the posting guidelines).



You're planning to take 56' boat that has only one outboard engine into the ICW and tidal coastal bays???



What's the beam to be (how wide)? The _link_ to your progress report doesn't work...maybe as a result of my moving your post



To try to answer your questions... Composting and incinerating toilets





Composting is a terrific concept, but IMHO, it's not quite there for
onboard use yet (if it ever will be). A true composter is quite large
and requires a considerable amount of maintenance. The only
self-contained composter that actually works as advertised is the
Sun-Mar unit...and it needs a space 29" high x 20" deep x 25" wide
(includes enough room for the handle on the side thatrotates the drum
and enough space to pull out the drawer), which is too big to fit in
99% of heads. The specs are the Sun-Mar website at:



http://www.sun-mar.com



Composting is a wonderful solution in on-land situations where there's
no sewer and septic is impossible, but in addition to the size problem,
there are also other issues onboard that don't exist in land situation:




1. what to do with excess liquids. 90% of human waste IS
liquid...mostly urine, but even solids are mostly liquid. Excess
liquids have to be drained off, or you have wet soggy organic
material...and wet soggy material doesn't compost. Adding
dry material--peat moss is the recommended material 'cuz it breaks down
quickly--to each flush helps some, but not enough, and there's usually
more liquids than the evaporator--which, btw, requires power--in the
self-contained units can handle either. You can't legally drain 'em
overboard (unless you're at sea), so they have to go into a holding
tank...and there goes any advantage to installing a composter even if
you have room in the head for it.



2. Enough peat moss to keep the thing working during an extended cruise can take up more storage space than a holding tank.



3. It needs a 3" vent stack...where are you gonna run THAT to???



4. It needs power to run the evaporator.



The AirHead
Airhead Toilet,
which is not a true composter, but a dessicator, is considerably
smaller, but also has many of the same issues--it also needs power
24/7/365...and urine must be stored in jugs that must carried ashore or
in a tank to be pumped out.



IMO, your best bet is a macerating electric toilet (the Raritan SeaEra
Raritan Engineering | Sea Era Electric Toilet
is an excellent choice), a Lectra/San or PuraSan (CG certified devices
that treat and discharge each flush overboard legally in all waters
except those specifically designated "no discharge"),
Raritan Engineering | Waste Treatment and a small holding tank for use only when you do find yourself in a "no discharge" harbor.



Yes, gray water can legally be discharged directly overboard in all US waters except for a few inland lakes.



As for hot water, the best way to go depends on what kind of power is
available....all electric marine water heaters require either
115v/ac--which means you'd need a generator--or a heat exchanger from
an inboard engine. There are propane water heaters...just be
aware of CG requirements for storage of propane tanks aboard.



Speaking of power requirements...what about stove and refrigerator--how do you plan to power those?



There's quite a bit more to spec'ing out the interior of a boat than
you may realize...it's not like designing a house on land... You need
to become very familiar with all USCG, ABYC, UL and other standards for
fuel and electrical systems, battery and any propane storage, etc...the
correct hoses to use for various systems...in fact, every system on the
boat.



And if I were you, I'd start following the weather and tide patterns
for all the waters you plan to cruise before committing to just a
single outboard...'cuz maneuvering a 56' boat that's essentially a
"house" on a floating dock in close quarters against a current in any
kind of wind is like trying park a billboard...you need all the power
you can get, and maybe even bow and stern thrusters too.

Peggie, thanks so much for the great reply. So much good information to mull over. And thanks for moving the topic...oops.

Here's the _link_ again; I've dropped the /boat.htm-- maybe going through the home page will work better.

http://reiheld.home.mchsi.com

This thing's going to be 56x18-- unless hisself gets tired of building pontoon 'barrels,' and decides that 48' is plenty.

As for power, I fumble-fingered, and dropped the 's'. We're planning to have a pair of 4-stroke outboards, probably 75hp or so each. Resident boatwright thinks (displacement) hull speed should be about 9 knots, with less than a foot of draft. Bow thrusters have been discussed, probably will be necessary, but not sure how that will work-- we'd like to try to avoid through-hulls if we possibly can. Still thinking on that, postulating absurd solutions like a steerable trolling motor-type thing, mounted forward, its shaft going down between the hulls. Discussing these ideas with local experts elicits predictable stare, grin, and incredulous shake of head. (OK, if yer gonna build a boat exactly like everybody else's boat, you might as well save time and money and go buy one that's already just like everybody else's, right?)

We have such gorgeous quiet backwaters around here for anchoring out, so I'd love to be as energy-self-sufficient as possible. Solar panels and deep-cycle batteries would be my first choice for powering a refrigerator and electric lights, if that's practical. Washer/dryer will most likely have to wait until we hook up to shore power. I'd figured on propane for stove, and on-demand water heater, storing the propane tanks under vented bench seats on the deck. I loathe the idea, but we'll have to spring for a gasoline powered generator, because we'll probably have install some sort of marine heat pump to moderate the southeast coast summers- and winters- from time to time. I don't guess we'll want to buy enough photovoltaics to run the a/c.

My rapidly fading hope for quiet energy independence is why the dessicator heads concerned me- seemed like they'd need a lot of power. Although the vent stack running up over the bimini, topside would probably not be much of a problem, I did wonder about odors from the pee-jug under the Envirolet, and other composters. And the good old close 'n' pump traditional head-- as a happy sailor in a former life, I have memories. pheeeeeeuuuu. I need to read your book, and learn the secrets. But I'll check out the Raritan, for starters. Thanks!

Again, thank you for the great advice. I'll look forward to learning much more-- I hope BEFORE we screw things up, rather than after.

Amelia

It's gonna be a pretty boat...but the fact that your RC model didn't
have any problems in a crosswind is not a good indication that the full
sized boat will. And I have serious doubts that even a pair of 75 hp
engines are enough to keep you out of trouble...that's a LOT of windage
to try to move with very little differential power! I think that
either Duke or UNC has a test tank in which they can create conditions
using models that replicate full size boats in real conditions. You
might want to talk their engineering school about the minimum power
needed for your boat in worst case conditions. That said, the
Honda 4-strokes are SWEET engines! Just make sure you put a big enough
pair of 'em on your boat.



Spring for a diesel genator...the CO emissions from gas generator
exhaust make it WAY too dangerous to run 'em overnight while you're
sleeping, which is when you'd prob'ly want it most. For more
information on the dangers of CO from gas engines and gensets
Google "CO deaths boats." A properly installed and exhausted
diesel, otoh, is safe enough to run overnight. Some 8"
oscillating 12v fans can often be enough, even on a hot night, to make
sleeping comfortable.



A properly installed and maintained marine toilet doesn't have to
stink...they've come a long way since you were a sailor. Do a
little homework on what's available now, and then I'll be glad to
answer your questions and even help you spec out the system.

Thanks a million, Peg. I'll get to doing the homework. I do appreciate and plan to take you up on your kind offer of help with the specs for the head system.



Now, following up on your thoughts re: outboard power, and other off-sanitation-topics, should I continue the discussion here, or switch to a different forum or send a private email? Such a resource- what a find!

Thanks

Amelia

This forum is "reserved" for sanitation and plumbing issues. I
suggest you post most of your questions about every other system in the
"building and restoration" forum. Start new threads for each
subject, and also each time you change the subject.