Plumbing Bilge Pump Discharge Hoses to Drain Manifold in Cockpit Locker

Last September we installed three electric bilge pumps in Pilgrim (see – Installing Electric Bilge Pumps.) The two pumps located lowest in the bilge discharge to the drain manifold in the aft portion of the cockpit locker.   The Morgan 382, 383, & 384’s designs have a unique drain system. If you are unfamiliar with the system check our July 30, 2014 post – New Deck & Bilge Pump Drain Manifold – for more info.

The discharge hoses for the lower two bilge pumps run up from the bilge to the area under the galley sinks.  Next they pass under the stove and under the ice box before reappearing along the foreword bulkhead in the cockpit locker.

Bilge pump discharge hoses run vertically along the new cockpit locker bulkhead

To prevent possible back flooding the discharge hoses must run to a siphon break located at point in the vessel that will remain above water level in all conditions.  We chose to install the siphon breaks in the hollow interior of the port cockpit combing.

Two siphon breaks mounted in stacked formation.

The siphon breaks are stacked vertically. The lower, 300G/H, pump requires a ¾” id hose.  The middle, 2000G/H, pump requires a 1-1/8” hose.  The middle pump discharge hose diameter is increased to 1-1/2” at the siphon break and continues at the larger diameter for the remainder of the run to the drain manifold.  90 degree elbows (pictured above) keep the hose runs compact, but elbows decrease the flow and can create back pressure that will reduce the effectiveness of the pump. Increasing the size of the discharge hose on the downstream side of the siphon break allows for the use of elbows without creating back pressure on the pump.

Earlier in cockpit locker refit we installed a ½” panel along the inside of the vertical cockpit seat back.

Purpose of panel along inside of port cockpit seat back is for mounting hose and wire runs.

The sole purpose of this panel is to provide a mounting surface for hose and wire runs.  We used sections of the retired aluminum angle from the salon (Aluminum Angle Brackets In Salon) to attach the plywood to the forward bulkhead and to panel we installed on the aft wall of the cockpit locker.

Siphon breaks and hose runs viewed from aft looking forward.  Hose on left is port deck drain.

Downstream of the siphon breaks the hoses remain elevated across the length of the locker. Upon reaching the locker’s aft wall they drop down to the drain manifold.

Drain manifold from left to right:
1-1/2" black hose is discharge for secondary 2000G/H bilge pump
3/4" black hose is discharge for primary 300G/H bilge pump
1-1/4" white hose is gravity fed port deck drain

More images and notes from this on-going project are available in the Cockpit Locker Refit Photo Album