mjm yachts 50z Downeast, Owner'S Manual

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9.1
9.2
9.3
9.4
GRAY WATER SYSTEM
GENERAL
Gray water is liquid that can legally be pumped overboard, generally from sink drains, shower
drains, and bilges. Your boat also directs deck run-off to of all gray water through common drains
(port & starboard) in the transom.
GRAY WATER SUMPS
There are two gray water sump boxes aboard your boat located (a) in the storage compartment
under the hatch in the cabin sole between the shower and head and (b) below the bottom
companionway step. These collect water from the shower drain, the dish locker drain, and the air-
conditioning condenser. The sump pump switch on the DC panel operates a bilge pump with
normal float switch to empty the tank when any of the above systems are in use. Periodically, the
cover of the tank should be removed and the contents/strainers cleaned.
BILGE PUMPS
There are three automatic electric bilge pumps fitted on your boat, plus an emergency manual
pump.
The manual bilge pump is located under the port piloting seat and is operated by opening the
plastic cover, inserting the handle, and pumping up and down. There is a noticeable difference
when the bilge has run dry. This pump is most often used as a back-up system to the 3 automatic
pumps. Its capacity is 15 gal/min.
The automatic pumps are located forward of the engine and under the companionway steps, are
wired directly to the house battery bank. This means that even when the main battery switches
are OFF, the bilge pump can continue to function properly. A three-way switch controls the
pumps. When held in the manual position, the pump will work regardless of whether there is
water in the bilge or not. In the OFF position, the pump will not turn on. In the AUTO position
operates if the water level rises. If water is detected, the pump continues to run until the water is
gone. Generally, the pump should be left in the AUTO position.
COMMON DRAINS
To eliminate unnecessary thru hull penetrations in the topsides, a common drain system is
utilized on both port and starboard sides. Make sure, especially when air-conditioning is running,
that the outlets for these drains, located in the transom under the swim platform, are not
obstructed. Items that drain into the common drains include: hatch gutters, galley and head sinks,
deck drains, sump tank and air-conditioning discharge.
CHAPTER 9