SJ23 Tech Tip E19, (Updated 2023-07-03) Bob Schimmel


Two Deck Wash Pumps for Panache - Portable & Fixed Mount.
INDEX - Uses, / Portable Pump, Parts / Fixed Mount Pump, Parts.

THE MAGIC OF RAIN OR DEW - It is incredible how well rain water can clean a deck.  Not many people wander around in the rain so they don't see this but next time, go on deck after a heavy down pour to see how clean it is.  That pristine deck surface demonstrates the cleaning power of rainwater.  Morning dew has a similar property and again most people don't see this, usually getting out of bed after it evaporates.  I'm not about to suggest you stand out in the rain with a deck brush, but if you get up a little earlier, you can brush the deck with the morning dew.  Either of these should be your first go to for cleaning the deck.  A past sailing buddy used to preach this philosophy to me all the time.  His deck was bone dry by the time anyone even thought about waking up.  He drove me nuts with this but had the cleanest boat in the club and he made good coffee in the morning!  There is actually a dust particle inside each rain drop that needs to be cleaned.  Didn't know that did you? 

WASH PUMP USES - For years I used a bucket of lake water and a brush to wash Panache's cockpit and deck.  A bucket is OK but frankly the swoosh doesn't wash debris away very well, especially along the cockpit toe rail where a steady stream of water can float debris away so it goes overboard.  A brush without flowing water is wanting to remove grunge from a tight space.  Nice to have endless water.  A deck wash pump is also quick and easy to clean a spill or remove foot prints from dirty shore based shoes. 
In addition, it can easily fill my solar water heater for a cockpit shower or fill the flush tank of the portable head.  What decadence.  For an emergency the portable pump it could backup an existing bilge pump by removing water from a cavity not serviced by a bilge pump (eg: cabin sole or under the forward berth).  It can also be used to remove water from my dinghy or an adjacent boat.  You get the idea, but lets not overrate this little pump.  And lastly it is a great way to wash an anchor lifted from a muddy bottom. 
I expect the pump will be used most of the time near the cockpit, in which case it will be hung over the side secured to a primary winch.  If I'm cleaning the cabin top or foredeck it will likely be hung from the centrally mounted spring cleat.

PORTABLE DECK WASH PUMP - The 12V centrifugal pump is mounted at the bottom of a 4' length of ABS pipe.  (In this fabrication I joined a 4' long 1.5" ABS pipe to an 8" long 2" pipe to use garage stock but a single 4' long 2" ABS pipe is probably simpler).  Using ABS pipe is perfect to keep the pump submerged and to protect it when the assembly is stored in the cockpit locker.  I chose a pump that is identical to those installed under the settees; serving as a spare that is known to work.  (See Tech Tip E16).  To use the portable pump hang it over the gunwale slung from a winch. 

- The electrical wires, vinyl hose and gunwale tie down line all exit at the top of the ABS pipe.  It takes a bit of clever thinking to fish the wires and vinyl tube down ABS and secure the pump inside, near the bottom, all the while keeping the vinyl tube attached to the pump.  I'll let you figure out that part but note the white tie wraps holding the pump inside the 2" section.  In reality it's too wordy to describe, but not that difficult to do.  You should also secure the wire, vinyl tube and tie down line at the top of the ABS pipe so you don't accidentally pull them off the pump.  The electrical plug draws power from the 12V jack on the breaker panel and the switch is located along the cord where it hangs just in the cockpit.  Its convenient to operate here and doesn't get beat up due to the cleaning task at hand. 
- A centrifugal pump can move more water in the forward direction than in the reverse direction.  The DC motor can turn in either direction and the positive lead is usually labelled.  If the power is applied to the motor so the pump operates in the forward direction you will see the stream going furthest out the nozzle.  This is the correct polarity to operate the pump, regardless of the lead labelling.  I found one pump to be labelled backwards!

This pump has a lift capacity of ~10' so it has sufficient force to do reasonable work.  The end of the tube might get a nozzle to create a more forceful stream of water but the biggest advantage is a steady flow of water. 

This pump is stored in the cockpit port locker with the wires and hose secured to the tube using a Velcro strap.  Later I may house it in a nylon bag.  Another thru hull installation adverted.

The first time I used the pump to clean the cockpit I was surprised with how well it worked.  Moving water is everything after all.  In half an hour I washed all the debris from the toe rails, under the mainsheet traveller, cockpit seat lids and the cockpit sole.  All winter debris that has a nasty habit of sticking around for the summer.  Its a great tool for emptying a dinghy filled with rain. 


  • 4' of 2" ABS pipe.

  • 1 Self priming bilge pump; CK-181DC, rated at 200 gal/hr, 1/37 HP, 12V, carbon brush motor, polypropylene impeller.  (See Tech Tip E16 for photo)
    - Tested to empty a 23L bucket in 1 min. & measured head of ~10'.

  • 15' of 1/2" vinyl tube.

  • 15' of lamp cord.

  • 1 12V accessory plug.

  • 1 lamp cord switch.   TOP

FIXED MOUNT DECK WASH PUMP - It can sometimes be difficult to keep a prairie boat clean, given the fine dust that blows off the fields in Spring and Fall.  Thankfully the open pit coal mine next to our lake is now closed.  While the combination of dirt and coal dust can bake quite hard on the deck, some sailors manage to keep their boat spotless.  I'm not sure where they find the time, because frankly I have other things to do.  One day I noticed one of those guys pointing his anchor hose to his deck.  "Hmmm.  A powerful deck wash pump that can push lots of water.  This might be just the ticket for heavy duty cleaning of the deck."  Now I wouldn't install a thru hull fitting just to have a deck wash pump because another hole through the hull is just plain dumb.  But, Panache has an idle thru-hull fitting that can be repurposed with a pump connected to it.  Come to think of it, this might come in real handy to fend off marauding "pirates" on the lake.

MECHANICAL - It took a fair amount of R&D to design a system within the constraints of Panache's existing port thru-hull.  I wanted the hardware to be out of sight plus be convenient to use and service.  The port settee satisfied many aspects of this with the pump resting on a plywood shelf next to the thru-hull fitting.  The epoxy coated shelf will keep the pump and electronics high and dry for most "wet" situations.  However, the pump and its electrical controls are installed on a small sub-board that rests loose on the shelf so it can align to the vinyl hoses and can be extracted for maintenance.

PLUMBING - Since the thru-hull is below the water line and the displacement pump is slightly lower, the pump should prime itself.  (Good in theory but I had to prime the pump by loosening the impeller cover and letting it bleed till the water was at the impeller.  It is not difficult to do).  The water protects the rubber impeller from a damaging dry start.  The thru-hull valve is closed between uses, for the obvious safety reason.  The 3' long pump inlet tube goes through an easy 3600 turn to prevent a kink that restricts water flow.  DO NOT use vinyl reinforced tubing as it kinks.  Instead, use coil supported tubing.  The pump outlet tube goes through the settee aft partial bulkhead, along the inside wall of the port cockpit locker to an RV "exterior spray port" installed through the aft cockpit wall under the tiller.  There is ample space for it back there.  The spray port is robust so no fear of creating a weakness.
- A 15' long vinyl coil discharge hose connects to the quick connect fitting of the external spray port.  The hose is self draining, kink & tangle resistant and collapses to (8x12)".  The soft outside is easy on the gel coat and takes far less space than a typical garden hose.  All useful features in the tight storage compartments on an SJ23.
- If there is any spilled water while disconnecting the hose from the spray port it will flow down the cockpit drains.  I expect this to be minimal.  The spring loaded check valve in the spray port is closed until a hose is plugged in.  However, I'm not relying on it to seal the spray port since is installed above the water line.  The last thing I need is a leaking valve to fill the hull; hence the practice of closing the thru-hull valve between uses. 

ELECTRICAL - A 12V pump that produces household pressure typically draws a lot of current.  The one on Panache draws ~10A and will therefore pull power through a dedicated 15A breaker, BKR 6.  The battery return wire connects to Buss Bar 4 (BB4) so the start up surge current cannot burn the shunt in the Load Meter M2.  The pump also has a 2A Transient Suppression Diode across it to short out any damaging voltage spikes when it powers off.  This diode must be capable of high current due to the size of the pump motor.  All wiring is #10 AWG stranded and has enough slack to extract the pump out of the settee for service.  The power is conveniently controlled by a Wireless Remote Controlled Relay Receiver to both conserve battery power and to minimize wear on the impeller when the nozzle is closed.  A rotating rubber impeller must always be lubricated and cooled with flowing water.  The Wireless Relay in turn drives a 50A relay to handle motor current.  I'll hang the FOB around my neck so I don't loose it overboard.  A manual power switch may be installed next to the pump for maintenance but so far has not been required.  The plan is to use the pump when the sun is shining so it can recharge the battery quickly and dry the deck.  In fact the short term, high charge, current may be beneficial, acting like a quick equalize charge to the battery.  In truth, the power consumption has proven no worse than starting the outboard and has not dropped the battery voltage during my trial tests.

OPERATION - Open the thru-hull valve and visually verify the pump is primed and not leaking.  Switch on (BKR 6).  Plug the hose into the spray port.  Point & open the nozzle.  Switch the pump on via the Wireless Remote Controlled Relay Receiver (configured for latching operation).  Wash the deck.  When finished washing, switch the pump off, drain the hose and pack it away, switch off BKR 6 and close the thru-hull valve.  I run the motor only to spray. 

WINTER STORAGE - All hoses and the pump must be bone dry to survive a winter freeze.  With the boat on the trailer I crack open the hose fittings at the pump, open the thru hull valve, plug the hose in the transom fitting, open the nozzle and let it all drain into the settee bilge.  There is actually very little water, that I wipe up with a sponge.  With the pump installed below Panache's galley at the aft end of the settee, it is a tad difficult to access the pump through the aft access hole.  For this reason I empty the galley to service the pump and hoses.  This is an inconvenience I can handle.



My design sketch of the shelf & deck pump installed at the aft end of the port settee.  The shelf with foot rest can just fit through the settee middle access hole.  A sub-board, housing the pump and electronics, rests on top of the shelf.  Since Panache's galley is installed on the settee above the pump, I have to empty the galley to service the pump.

I heard many interesting opinions about a deck wash pump from local sailors.  Most liked the idea of an easy way to clean the deck but few were willing to install one.  They all had an opinion of which type hose to use though.  Some liked the coil hose, others liked the collapsible hose.  Go figure.  So a field trial was in order. 

During a bench test, this pump, coil hose and nozzle combination produced flow similar to a garden hose.  This is sufficient to clean the cockpit (usually the dirtiest) and the cabin top (next dirtiest).  The coil hose can stretch to ~10' but it is difficult to clean the foredeck from the front of the cockpit.  The force is sufficient to wet the deck though. 

Cleaning the anchor is seldom required on our lake.  If it is I motor for a short distance with the hook hanging in the water to wash the mud off.

The pump, wireless remote control and relay assembled on the sub-board.  The electrical connections are coated in ATF to prevent corrosion.

Preliminary assembly under the settee.  Note the easy turn (no kinks) of the vinyl inlet tube suspended by Alien Tape from the settee top.  It was replaced with reinforced tubing.

The pump outlet tube goes through the aft settee bulkhead at the top left corner.  After that the hose goes on its merry ole way through the cockpit locker to the spray port.  The detached hoses on the left are for the grey water tank removed for this photo.  This is a crowded space but all the critters seem to be happy!

A robust "exterior RV spray port" to be installed in the aft end of the cockpit, under the tiller.  This spot is clear of obstructions inside the transom.

The coil hose e/w mating quick connector that plugs into the spray port fitting.  It may be replaced by an expandable hose that has the advantage of storing pressure, useful for a quick burst of water without operating the pump.


Transom hole being tapered and expanded to fit the spray port.


Without these fittings the tube kinks & restricts the water.


Its a lot easier to pull the vinyl tube up through the hole than push it, given the very long reach from inside the port cockpit locker.  Drop a test cord through the hole, clip it to the tube and pull it up, carefully.  Done!



At right is an expandable hose in use.  I prefer this style hose to the coil version shown above as it has freedom to move. Draining the hose involves opening the nozzle and lifting it.  The water will finds its way out the end!

The cockpit is filthy due to work I was doing on an adjacent boat.  I hate that it doesn't show through the camera lens.  See its clean below!


Completed spray port installed under the tiller.

Finished spray port installed under the tiller.

Pump in operation.  (Future)

Pump in operation.  (Future)

NOTE - Ultimately you could use a deck wash pump as a fire extinguisher, for yourself or another boat.  Although, you better have a high volume pump to be effective.  Just a thought.


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