Hints and Tips



SO40 Galley Sink Upgrade

Copyright 2017 Karl D. Lahm


Over the three years from the date we acquired Voyageur until the completion of this upgrade, both galley sinks didn’t drain well. Worse, one would drain into the other. Water from the adjacent sink would push up on a stopper and at least loosen it. The Admiral (a/k/a SWMBO) was not amused by this.

The original Jeanneau sink drain scheme has a pair of sink tailpieces with 90° hose attachment points, 1” (25 mm) in diameter. These connect to a single-piece drain hose that includes a tee below the sinks, which is attached to the forward surface of the cabinet under the galley sink using cable ties. Of course, these ties deform and constrain the hose. Was hose deformation or waste collection at the tee junction and/or points of deformation the problem? Perhaps, but I didn’t disassemble this configuration to find out, as other considerations encouraged its complete replacement.

This upgrade was actually inspired by another – the upgrade of the refrigerator mechanical system to the Isotherm self-pumping scheme. Central to this system is a new, much larger galley sink through-hull, which contains the refrigerant-to-seawater heat exchanger coil. This through-hull has an inlet diameter of 1½” (38 mm). After looking at various adapter fittings, none of which seemed to interface the 1” hose to the 1½” through-hull very well, I decided to rebuild the sink drains using all 1½” (38 mm) connections.


Tailpiece Replacement and Tee Connection


LIRA, the Italian manufacturer of the sink drains offers two different tailpipes that fit the drains. One is the 90°, 1” (25 mm) unit that the boat was delivered with, while the other (part number 1911) has a 1½” (38 mm) ID diameter plastic pipe socket that is oriented straight down. In the USA, these are imported by Scandvik - part number 10312 and resold by several marine suppliers.

I acquired a “sink drain kit”, containing all of the plastic pipe materials needed to connect the two sinks together, for the princely sum of $7 USD, at a local home center’s plumbing department. Each arm of this assembly fits directly into the new sink drain tailpieces, while the outlet of its tee section is readily connected to 1½” ID hose that leads to the new through-hull’s hose barb. The entire assembly below the sink is shown by the pictures taken through the cabinet door, sideways and looking upward, below. The gray tailpieces fit the sink drains exactly. The tee section connection to the hose leading down to the through-hull port also fit exactly. The hose was acquired from the local hardware store.

P Sink drains viewed through cabinet door                                       Sink drains viewed from below

Cabinet Wall Notch


Like all boat DIY projects, this one had its complication, the cabinet divider wall between the cabinet under the galley sink and the leftward cabinet, where the utensil drawer is located. This wall obstructs the path of the pipe from the left-hand sink tailpiece to the tee. A slot was cut in it to clear the 90° drain connection piece, as shown in the right-hand photo below.

Through-hull assembly, cutoff valve, and drain hose                       Left sink drain arm showing notch in cabinet wall

The shelf above the utensil drawer also restricted the pipe’s installation. An indentation was filed in that shelf to a depth that cleared the pipe. Once this was done and the 90° connecting pieces shortened to fit the sink drains’ spacing, everything fit together easily. My apologies, to the woodcraft perfectionists, for the veneer torn away below the notch. This was caused by impatient filing, inside the sink cabinet, where no one will see it!.

Cabinet wall notch showing indentation                                          Left sink drain pipe clearance through notch

Scandvik offers a double sink drain kit (part number 10310) that appears to require less clearance under the left-hand sink. However, Voyageur has a trash container attached to the galley sink cabinet door, which the tailpipe of the Scandvik kit would likely obstruct. Though this appears to be a LIRA product, it could not be found on that manufacturer’s web site, so I cannot provide a LIRA part number for the non-USA majority of the world. Where clearance within the under-sink cabinet is not an issue, this kit may be a more elegant approach, but the drain hose will need to be more flexible than the one I used.




The end result was a drain scheme entirely made of 1½” (38 mm) inside diameter components, with minimal deformation of the connecting hose by its supporting straps. The tee section has a baffle in it that discourages water flow between sinks. Drainage is now excellent, without flow from one sink into the other. A side benefit is that the reinforced clear tubing used between the sink tee and the through-hull fitting shows the waterline readily, making it easy to determine what features within the cabin are above and below that line. And, should waste clog the hose, the obstruction will be visible!


Copyright 2017 Karl D. Lahm