Hal Landen wrote:
I'm planning to install a new holding tank system in my 1959 Pearson
Triton Yawl. According to Peggy Hall in "Get Rid Of Boat Odors" it is
recommended that the vent in a holding tank be 1". But the standard
for 20 gallon tanks seems to be 5/8". It is better to cut a new 1"
vent outlet or live with the exisiting 5/8" vent?

You already know what I'd recommend. There's a doodad called the
UniSeal--available from these folks http://www.aussieglobe.com/avs96.htm
--that makes it fairly easy to install a new vent fitting.

You'll also want to get your 1.5" sanitation hose from them, btw. AVS96
is the same hose SeaLand sold exclusively in the US for several years
under their private label brand name "OdorSafe"...now sold direct from
the mfr under their own brand name for $5/ft, cut to any length...which
is about half what SeaLand's price was. Use Shields or Trident #148 for
sizes other than 1.5".

Now back to your tank...you don't have to settle for the meager choice
of rectangular thin-walled tanks with "standard" fittings locations and
vents that are actually the standard for fuel and water tanks...check
out Ronco Plastics at http://www.ronco-plastics.com They make top
quality tanks that are at least 50% thicker than off-the-shelf tanks for
a very reasonable price...have more than 400 shapes and sizes, including
over 100 non-rectangular...and install fittings in the sizes and
locations specified by the customer when they make the tank.


--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://69.20.93.241/store/customer/p...40&cat=&page=1