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Bilge Pump, Extending the intake
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Repair and Maintenance of a Drascombe Lugger

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Extending the Bilge Pump Intake

The Problem Defined

This sketch shows the original unmodified bilge pump intake pipe. With the boat afloat and with normal fore and aft trim, a considerable amount of water can collect in the bilge at the front of the boat. This water is out of reach of the pump intake pipe.

This sketch shows how the problem was solved. The intake pipe was extended forward, along the base of the centreboard case, using standard 22mm diameter copper water pipe. Associated fittings were an end cap and elbow (both soldered in place), and plastic pipe clips to hold the pipe in position.

Required Fittings

The following tools & materials are required;

• One 2 metre (6.5 feet) length of 22mm diameter copper water pipe.
• A 22mm diameter copper end cap (with internal solder ring)
• A 22mm diameter copper elbow (with two internal solder rings)
• Butane blowtorch (as shown) or hot air gun (not shown in photo)
• Plumber's flux
• Steel wool (for cleaning the pipe and the inside of the elbow and end cap prior to soldering)
• Stainles steel jubilee clip, for attaching the intake hose to the copper pipe of the extension (not shown in photo).
• 2 plastic 22mm pipe clips, with 2 stainless self-tapper or wood screws (not shown in photo)
• 2 pieces of hardwood measuring about 25mm square by about 17mm thick, to support the pipe clips (not shown in photo)
• Epoxy glue for gluing hardwood pipe clip supports to hull (not shown in photo).

Step by Step Guide

	Step 1: Measuring up Remove the floorboards on the port side of the centreplate case and measure the distance between the bottom of the bilge pump intake pipe, along the bottom of the boat (adjacent to the centreplate case), to the front of the case (See sketch). This should be about 50 inches (1270mm). (Click on image for larger view)
	Step 2: Positioning the pipe Use a hacksaw or tube cutter to cut the copper tube to the length determined in Step 1 (about 50 inches or 1270mm). Take the two plastic pipe clips and, using two stainless self-tapping screws, screw them to two small (25mm x 25mm x 17mm) hardwood blocks. Attach the clips (push fit) one at each end of the copper pipe. Lay the pipe on the hull, adjacent to the centreplate case, so that one end is beneath the intake pipe of the bilge pump and the blocks are resting on the bottom of the boat. Adjust the position of the two plastic clips (plus attached wooden mounting blocks), by sliding them along the copper pipe until the end of the pipe at the front of the centreplate case is about 4mm above the hull (bottom of the boat). Use a pencil or felt tip pen to draw round the position of the mounting blocks on the hull. This is where they will be glued to support the pipe in the correct position. (Click on image for larger view)
	Step 3: Glueing the Pipe Mounts in Position Remove the clips from the pipe. Abrade the GRP of the hull where the wooden mounts for the pipe clips are to be glued in position. Next, mix up some Epoxy and, using a small brush, apply a generous coating to the wooden mounting blocks (to prevent water damage). Stir in some thickener to the remaining Epoxy (West 404 filler for example), to convert it into a glue. Apply it either to the base of the wooden blocks or to the abraded parts of the hull where the blocks are to be affixed. Place the blocks in position and allow the Epoxy to cure. The blocks are now glued in the correct position. (Click on image for larger view)

Soldering the End Cap

Why use an endcap?
If the end of the intake pipe is left un-capped then debris in the bilge water can be sucked in and block the pipe and the pump. The end cap completely covers the intake end of the pipe, but a series of small 2mm holes drilled in the copper pipe adjacent to the cap, forms a STRUM allowing the pumped water to be filtered free of coarse debris. See below for more details.

The first stage is to solder the end cap to the copper pipe. You should, if possible, purchase the end cap with an internal solder ring 'built into' the component so that no additional solder is required.

Photographs showing the stages in soldering the end cap to the copper pipe.

Step 1 The end of the pipe should be cleaned with steel wool until the metal is bright and shiny

Step 2 The inside of the end cap should also be cleaned to a bright finish with the steel wool.

Step 3 Smear some flux on the end of the pipe .....

Step 4 .... and on the inside of the end cap.

Step 5 Place the end cap on the end of the pipe ensuring that the end of the pipe is pushed right up inside the cap. Wipe off excess flux with a paper towel.

Step 6 All ready for soldering.

Step 7 Applying heat to the joint. This can be done with a blowtorch, or a paint stripper type heat gun set to maximum heat (as shown in picture 7). Note, it takes longer to reach the correct temperature with a heat gun than when using a blow torch.

Step 8 Watch the bottom of the end cap whilst heating. Completion is when a bead of white solder appears all the way round the joint. You can see the difference by comparing Photo 6 (before), with Photo 8 (after). Remove heat immediately and allow to cool. The end cap has been successfully soldered in position.

Soldering the Elbow

The next stage is to solder the other end of the 1270mm long pipe to to a shorter length of about 70mm (2.75 inches), using an elbow (90 degree) joint. You should, if possible, purchase the elbow joint with two internal solder rings 'built into' the component so that no additional solder is required

The process is similar to that of soldering the end cap, the main difference being that there are TWO JOINTS on the elbow and the soldering of both joints must be done in a single operation.

Photograph showing the set up for soldering the elbow to the copper pipes.

The ends of the pipes should be cleaned with steel wool until the metal is bright and shiny. Likewise the inside of both ends of the elbow joint. After smearing the cleaned pipe ends and the inside of the elbow with flux, the pipes are assembled as shown ready for heating. Make sure that the ends of the pipes are pushed right up into the top of each arm of the elbow joint. Heat (by blow torch or hot air gun), is directed to the centre of the elbow. Look for the tell-tale bead of solder to appear at the joints on both sides of the elbow. If the bead appears at one joint and not at the other, direct the heat towards the unsoldered joint until the bead appears there as well. Remove heat immediately and allow to cool. That completes all the soldering operations that are required.

Making the STRUM

Next, a series of small holes are drilled in the pipe adjacent to the end cap to form a STRUM which acts as a filter to prevent debris in the bilge water being sucked in and clogging the pipe & pump.

Making the STRUM Place the pipe with the elbow pointing down in a table vice.The STRUM (filter) is simply made by drilling a series of small (2mm diameter) holes in the copper pipe, over a distance of bout 60mm, behind the end cap on the upper half of the pipe as placed in the vice. This will form the lower half of the intake pipe when installed in the boat. To make the hole spacing conform to a regular pattern, some mm graph paper can be temporarily taped on the end of the pipe and the squares used as a guide when drilling the holes. (Click on image for larger view)

How it all fits together

How it fits together It is impossible to photograph all the components in place on the boat, so this photograph shows how all the components (including the bilge pump itself), fit together laid out prior to installation. Note that it is most important that a polythene hose is used to make the connection between the intake port of the bilge pump and the end of the copper intake pipe (above the elbow). Without the flexibility of the hose, it is impossible to connect between the two rigidly fixed components (the pump and the copper intake pipe). See below for installation guidelines. (Click on image for larger view)

Installation

Installation is a bit fiddly & requires a bit of patience! Assuming that the bilge pump is in place on the boat, the installation steps are as follow.

• Existing hose or pipe is first removed from the intake port of the bilge pump
• Clip the copper intake pipe in place along the base of the centreplate case so that the short intake end of the pipe (above the elbow), is pointing towards the plastic intake port of the pump.
• To find out how much polythene hose is required, measure the distance between the end of the pipe and the intake port of the pump. Add another 50mm (2 inches) to this measurement, so that one end of the hose can be push fitted to the plastic pump port and the other end push fitted onto the copper pipe.
• Cut a length of 25mm diameter polythene hose to the measured length.
• Push fit one end of the hose on to the plastic intake port of the pump and secure with a stainless Jubilee clip.
• Temporarily unclip the copper intake pipe from the push-fit plastic clips to enable the other end of the polythene hose to be push fitted on the end of the pipe above the elbow.
• Re-attach the pipe to the push-fit plastic clips (along the side of the centreplate case) re-adjusting the polythene hose as required. The hose may need some more trimming or the push-fit on the copper tube adjusted to allow the copper pipe to be clipped in place.

Extension installed With the floorboards and the wooden top of the centreplate case removed, this is the best photograph obtainable of the completed installation. It shows the extension pipe, running along the side of the centreplate case and held in place by the plastic clips mounted on their wooden-blocks. (Click on image for larger view)

This completes the installation and should ensure that most bilge water can be effectively pumped out from the front and lowest part of the boat when afloat.

Project started and completed July 2006