"Larry" wrote in message
...
http://www.lavac.com/

I found the website of the really great marine head installed on a
racing trimaran that's visiting Charleston this week. After struggling
with those cheap plastic crappers from Waste Marine all clogging and
sticking plastic valves and the damned pumps that you have to keep
greased....THAT STINK....

If you've never seen this toilet, or used it, or flushed it, look out
for it....

The model installed on this spartan trimaran is the simplest thing I've
ever seen. The seawater seacock through the hull is right behind it and
there is a water loop with an anti-siphon U in the top of it because in
this boat the toilet is far below the waterline and would flood the hull
otherwise. There's NO PUMP, NO PARTS, NOTHING MOVING in the head,
itself! The head is simply plumbed with plastic bilge pump hose to a
regular Whale diaphram bilge pump surface mounted high on the bulkhead
behind and to the side of it so you don't bump your head while seated.
The outlet of the pump goes into the Y-valve to select sanitary tankage
or overboard discharge. After the pump, it's the same old sewer system
any boat has....way too small to hold much for long.

You have two choices to flush....

Leave the seat OPEN and it merely pumps out whatever's in the bowl until
it sucks air....LOTS OF AIR! That diaphram pump isn't that crappy
little plastic pump on the head you have now...and it works SO EASY WITH
SUCH A SHORT LIFTING HOSE...ABOUT 3' so the pump is ABOVE the waterline
and can't backfill the boat if one of its valves is stuck open. If you
want to use up your fresh water to flush with the shower head, this
allows it just fine.

Leave the seat CLOSED and it's a full-blown, self-flushing vacuum toilet
because the seat seals to the toilet and the lid seals to the seat VERY
TIGHTLY WITH A SOFT PLASTIC SEAL ON BOTH ON THE BOTTOMS. You hear a
sound that sounds like one of those tankless gas station toilets
flushing when you pull the big handle on the 1" water line that feeds
them! This puppy flushes HARD on that much vacuum from the Whale pump!

Running on 1 atmosphere of PRESSURE, 14 PSI, I don't think ANYTHING that
can be sucked down that tube could EVER clog it up!

Now the important part......IT SAYS SUCKED SHUT VERY TIGHTLY AFTER THE
FLUSHING STOPS! The suction comes from an intake valve that won't let
the toilet flow go backwards towards the seacock. As this valve, which
must be a simple flapper, is on the seawater side, nothing in the toilet
will clog it up and with this much pressure I cannot imagine anything
from the sea stopping it from opening.

To flush you need only close the lid and make TWO pumps on the Whale.
Now SEALED, the toilet CANNOT SMELL UP THE BOAT! God, where was this
when I used to have to stand watch downwind from the stinky heads in
cruising boats?!

Yes, Larry, I had one in a previous boat and it is just like you say but a
very big disadvantage is that if there is a queue for the heads the next
person is going to find the lid securely vacuumed shut until it slowly leaks
its vacuum away and that takes some time.
.. Sometimes people get so frustrated that they heave the lid up and then
find that the sealing ring has pulled out of its groove and has to be
pressed back in before it can be used again. Not always a nice job on a head
that many people have used in rough sea conditions!!!

"Larry" wrote:

I found the website of the really great marine head installed on a
racing trimaran that's visiting Charleston this week.

Your basic Lavac from Blakes in the UK.

Available in US from Defenders and Brendens Isle, in Florida, started
by Tom O'mera many years ago.

Uses basic Henerson MKV pump (Waste waater version of Whale 10).

Small pin hole in incoming vacuum line eliminates "stuck seat" problem
after using. (Design per Tom O.)

Next question.

Lew

Lew Hodgett wrote:
"Larry" wrote:

I found the website of the really great marine head installed on a
racing trimaran that's visiting Charleston this week.

Your basic Lavac from Blakes in the UK.

Available in US from Defenders and Brendens Isle, in Florida, started
by Tom O'mera many years ago.

Uses basic Henerson MKV pump (Waste waater version of Whale 10).

Small pin hole in incoming vacuum line eliminates "stuck seat" problem
after using. (Design per Tom O.)

Next question.

The pin hole does not necessarily do the trick - it depends on the
geometry. On my setup it takes several minutes to release by itself. I
can pry it with my fingertips after about 15 seconds, but my daughter
can't do it.

"Jeff" wrote:

The pin hole does not necessarily do the trick - it depends on the
geometry.

Don't remember the specifics, only the pin hole was req'd.

Alternate is to use potable water from shower wand and leave lid up
till pumped dry.

Lew.

On Nov 17, 4:29*pm, Jeff wrote:
....
The pin hole does not necessarily do the trick - it depends on the
geometry. *On my setup it takes several minutes to release by itself. *I
can pry it with my fingertips after about 15 seconds, but my daughter
can't do it.

Right, it is important that the pin hole is at the top of the intake
line and that the intake is set-up so no water can collect between the
pin hole and the head. If you have a sag in the intake line between
the pin hole and the head it will negate the pin hole and you'll have
to wait for the air to leak into the head through the water and seat
seals. That seems to take minutes. With a proper set-up you you
should be able to open the lid in 15 ish seconds.

FWIW, I met a guy who had taken a regular home toilet and converted it
to a Lavac like system by making a top that could be sealed down when
the toilet seat was up. Seemed to work like a charm.

Sorry for the hurried reply. We're in Ensenada, Mexico and I'm paying
for 'net time.

Cheers to the group,

--Tom.

Hey! Glad all is well... trip report?

wrote in message
...
On Nov 17, 4:29 pm, Jeff wrote:
....
The pin hole does not necessarily do the trick - it depends on the
geometry. On my setup it takes several minutes to release by itself. I
can pry it with my fingertips after about 15 seconds, but my daughter
can't do it.

Right, it is important that the pin hole is at the top of the intake
line and that the intake is set-up so no water can collect between the
pin hole and the head. If you have a sag in the intake line between
the pin hole and the head it will negate the pin hole and you'll have
to wait for the air to leak into the head through the water and seat
seals. That seems to take minutes. With a proper set-up you you
should be able to open the lid in 15 ish seconds.

FWIW, I met a guy who had taken a regular home toilet and converted it
to a Lavac like system by making a top that could be sealed down when
the toilet seat was up. Seemed to work like a charm.

Sorry for the hurried reply. We're in Ensenada, Mexico and I'm paying
for 'net time.

Cheers to the group,

--Tom.



--
"j" ganz @@
www.sailnow.com

Edgar wrote:
"Larry" wrote in message
...
http://www.lavac.com/

I found the website of the really great marine head installed on a
racing trimaran that's visiting Charleston this week. After struggling
with those cheap plastic crappers from Waste Marine all clogging and
sticking plastic valves and the damned pumps that you have to keep
greased....THAT STINK....

If you've never seen this toilet, or used it, or flushed it, look out
for it....

The model installed on this spartan trimaran is the simplest thing I've
ever seen. The seawater seacock through the hull is right behind it and
there is a water loop with an anti-siphon U in the top of it because in
this boat the toilet is far below the waterline and would flood the hull
otherwise. There's NO PUMP, NO PARTS, NOTHING MOVING in the head,
itself! The head is simply plumbed with plastic bilge pump hose to a
regular Whale diaphram bilge pump surface mounted high on the bulkhead
behind and to the side of it so you don't bump your head while seated.
The outlet of the pump goes into the Y-valve to select sanitary tankage
or overboard discharge. After the pump, it's the same old sewer system
any boat has....way too small to hold much for long.

You have two choices to flush....

Leave the seat OPEN and it merely pumps out whatever's in the bowl until
it sucks air....LOTS OF AIR! That diaphram pump isn't that crappy
little plastic pump on the head you have now...and it works SO EASY WITH
SUCH A SHORT LIFTING HOSE...ABOUT 3' so the pump is ABOVE the waterline
and can't backfill the boat if one of its valves is stuck open. If you
want to use up your fresh water to flush with the shower head, this
allows it just fine.

Leave the seat CLOSED and it's a full-blown, self-flushing vacuum toilet
because the seat seals to the toilet and the lid seals to the seat VERY
TIGHTLY WITH A SOFT PLASTIC SEAL ON BOTH ON THE BOTTOMS. You hear a
sound that sounds like one of those tankless gas station toilets
flushing when you pull the big handle on the 1" water line that feeds
them! This puppy flushes HARD on that much vacuum from the Whale pump!

Running on 1 atmosphere of PRESSURE, 14 PSI, I don't think ANYTHING that
can be sucked down that tube could EVER clog it up!

Now the important part......IT SAYS SUCKED SHUT VERY TIGHTLY AFTER THE
FLUSHING STOPS! The suction comes from an intake valve that won't let
the toilet flow go backwards towards the seacock. As this valve, which
must be a simple flapper, is on the seawater side, nothing in the toilet
will clog it up and with this much pressure I cannot imagine anything
from the sea stopping it from opening.

To flush you need only close the lid and make TWO pumps on the Whale.
Now SEALED, the toilet CANNOT SMELL UP THE BOAT! God, where was this
when I used to have to stand watch downwind from the stinky heads in
cruising boats?!

Yes, Larry, I had one in a previous boat and it is just like you say but a
very big disadvantage is that if there is a queue for the heads the next
person is going to find the lid securely vacuumed shut until it slowly leaks
its vacuum away and that takes some time.
. Sometimes people get so frustrated that they heave the lid up and then
find that the sealing ring has pulled out of its groove and has to be
pressed back in before it can be used again. Not always a nice job on a head
that many people have used in rough sea conditions!!!


Can a vacuum release be added to let the air in the bowl?

Boeland wrote in news:4921bc34$0$14489$5fc30a8
@news.tiscali.it:

Can a vacuum release be added to let the air in the bowl?



I don't understand this vacuum problem. Just pull on the cover and it
bends to leak air into the bowl. It's no problem at all on the one I used.
It's not like it's sucked flat and noone can open it. There's a hissing
sound when you pull on it and the vacuum is released. The idea of LEAVING
IT SEALED is WELL worth any trouble opening it......THERE's NO SMELL AT ALL
IF ITS SEALED SHUT!

There's also no "seawater smell" wafting up when water is left in it, even
shut with no vacuum on it....that's great, too!

Larry wrote:
Boeland wrote in news:4921bc34$0$14489$5fc30a8
@news.tiscali.it:

Can a vacuum release be added to let the air in the bowl?



I don't understand this vacuum problem. Just pull on the cover and it
bends to leak air into the bowl. It's no problem at all on the one I used.
It's not like it's sucked flat and noone can open it. There's a hissing
sound when you pull on it and the vacuum is released. The idea of LEAVING
IT SEALED is WELL worth any trouble opening it......THERE's NO SMELL AT ALL
IF ITS SEALED SHUT!

There's also no "seawater smell" wafting up when water is left in it, even
shut with no vacuum on it....that's great, too!

The issue is that a considerable vacuum is created while pumping. There
should be a pinhole in an intake line loop to serve as a anti-siphon
vacuum break. This also bleeds off the vacuum in the bowl, and allows
the bowl to fill after pumping, but how fast this happens depends on how
far the bowl is from the loop and the size of the hole. With no
pinhole, it can be impossible for someone unfamiliar with the system to
open it; as I said I can usually pry mine pretty easily but my kid can't
do it within 10 minutes of a pump.

In article , Jeff wrote:
The issue is that a considerable vacuum is created while pumping. There
should be a pinhole in an intake line loop to serve as a anti-siphon
vacuum break. This also bleeds off the vacuum in the bowl, and allows
the bowl to fill after pumping, but how fast this happens depends on how
far the bowl is from the loop and the size of the hole. With no
pinhole, it can be impossible for someone unfamiliar with the system to
open it; as I said I can usually pry mine pretty easily but my kid can't
do it within 10 minutes of a pump.

Has no-one thought of a something like a pressure-cooker sprung valve in
the lid - only in reverse? Just press to let air in and break the seal.

Justin.

--
Justin C, by the sea.