Flooding header
A cautionary tale.

dock connectionBoat connectionFreshwater water pipes can be seen connected to lots of boats in marinas, especially liveaboards. A hose is connected from a faucet on the dock to a pressure-reducing inlet valve on the boat, which reduces municipal water pressure, usually around 60lbs, to about 35lbs. This pressurizes all the water outlets on the boat, and has some advantages: constant pressure at all outlets, no noisy electric pumps; a more even and usually stronger flow than a pulsating pressure pump, for say, a shower; silent operation; no drain on the batteries; water is fresh from the shore, instead of the tanks.

My 45-foot schooner Britannia had the system installed by the boat makers. The 1/2” inch diameter Original pipeworkplastic water pipes were therefore as old as the boat, circa 1978, with a maze of connectors all in a tangled mess in the bottom of the bilge. I was frequently repairing or replacing sections that leaked, or which cracked from time to time, and which the automatic bilge pump would always alert me to, by switching itself on. I was very aware the whole system needed upgrading, but so did many other things on the boat. We didn't live aboard, so it was more a question of fixing the pipework as and when it broke.

Machinery bayThe Down East 45 is a long keeler with an abnormally large bilge, it runs 26’ feet under the floorboards and is 4’ 6” inches deep to the Ladderkeelson below. This cavernous area contained the Perkins main engine; a Kubota generator; 22 gallons water heater; 10 batteries and 8 electric pumps. It is an extremely large area, which I call the machinery bay. I actually built a wooden ladder to climb up and down in safety.

It was always my practice to turn the water off at the dock whenever I left the boat, even for a short time, and when I left it for days, I would disconnect the hose at the faucet. Except for this one time, when I forgot, but I was only in town for a few hours... Upon returning to the boat, I immediately noticed the air conditioning had stopped, which was unusual; so I lifted a floorboard to check the water circulation pump, and received the shock of my long and varied sailing life! Water was sloshing about 12 inches below the floor beams.

I don't remember my actual words, but they definitely couldn't be printable here.

Manning the pumpsPortable pumpI confess I totally freaked out and didn't even think to test the water to see if it was fresh or saltwater that would have immediately pointed me to a possible source of the flooding. Instead, I dashed to the Marina office, only to be told their portable pump was, “waiting for parts.” I went to the engineering shop nearby and implored their help to, “man the pumps.” Jeff Belford, owner of Boaters Edge, (boatersedge.net) came over immediately, trundling a massive gas engine pump with a very long 3” inch diameter hose. After some heart-stopping moments, it roared into life, and I shoved the suction end into the water, which still seemed to be rising. The pump soon started to reduce the water level, which was well over my eight brand-new batteries, all the pumps, and halfway up the engine and generator. The boat seemed to be down on her marks about twelve inches—that’s some water in a 45’ footer!

As the powerful pump began to make its mark, cooler thoughts began to prevail and I tested the water with a finger. It was definitely freshwater, and that was when I realized the dock hose was still switched on. A crowd had gathered by this time and I was embarrassed to ask someone to close the tap. It seemed like an eternity before the water receded, to expose first the batteries, then the various pumps and motors which operate all the boat systems.

Twin pumpsIn total there are four electric motors on the electric toilets waste systems; a large 120-volt air conditioning circulation pump; a big water pressure pump; a deck-wash pump and the generator electric fuel pump. That's eight electric motors; not to mention the two large starter motors and their solenoids for the main engine and diesel generator. All these had been completely submerged, including the main engine gearbox.

As the water receded below the battery tops, the twin bilge pumps miraculously started up and did their best to help the big pump. It had undoubtedly been overwhelmed with the powerful inflow, then shorted out as water covered the batteries.

Even after the water was eventually pumped out, I remained in a state of shock. Worries about the damage and cost overwhelmed me, especially since much of the equipment was new and still under warranty: like $1000 worth of new batteries; $2,850 for a new generator, and many of the pumps. Thoughts of what was now swilling inside both the engine and generator motors made me feel physically sick. I found it difficult to formulate a list of priorities in my mind.

I began by unscrewing each battery filler plug and testing the specific gravity with a hydrometer. They were normal, and the rims of the plugs were dry. It seemed that no water had entered, and freshwater might not have done serious damage anyway. I withdrew the main engine dipstick, which showed a layer of milky oil, as did the generator engine. Water could also be seen up to the filler neck in the gearbox. I needed to get it all out urgently!

I opened the engine oil drain plug and the catch pan filled with a creamy mixture of oil and water. The generator contained the same mixture, which I drained into a bucket. The transmission drain plug was completely inaccessible under the gearbox, so I used a 1/4” inch neoprene tube and a small portable impeller pump, to suck the oil out.

I knew I needed to start the engines as quickly as possible—always assuming the starters worked. I rushed to a nearby garage and bought five gallons of their cheapest oil. There was little point in buying good quality because I knew one oil change would not be enough to eliminate the water. I had plenty of spare filters. I also bought a hair drier in the hope of drying out some of the electrics.

The 4” inch-diameter engine room blowers had not been submerged, so I switched these on to start a fast airflow throughout the whole machinery bay, venting out the stern. By now it was late evening and the equipment was not the only thing completely drained. I simply couldn't face trying to start the engines, so I had a few beers and went to bed. I did not sleep well. At about 6 am, I began refilling the diesel engines and transmission with new oil. I drained them once more, then refilled them again with new oil and filters. By this time both engines had had 24 hours to drain any water into their pans. I used the hair drier to warm up the starter motor, and it was now time to bite the bullet. I said a little prayer as I pressed the starter switch, but Hair driertrusty old “Perky” burst into life immediately. Wow!!

Before trying to start the Kubota diesel, I disconnected the electrics in the generator control box. This prevented the generator from making electricity, yet allowed the rotor to spin and clear any water inside—that is, assuming the engine started. I treated it the same as the other starter, I pressed the “go” button and it turned over sluggishly, then fired. Yippee! How on earth these two starters worked, having been completely submerged, I have no idea, but I was not complaining.

I knew it would be beneficial if I could get some dry air into the equipment bay, so the next items were the two air conditioners. The 120-volt pump, which pumps seawater through the AC units, is an open windings type motor, so I used the hair drier to blow hot air into it for ten minutes. The actual AC units are mounted high and were not flooded. As I started one air conditioner, I heard the pump start-up and a quick inspection outside told me that water was being pumped through both units. Another lucky break!

Ropes dryingwater pressure pumpEverything else needed individual inspection, so I decided to start forward and work aft. This began with the electric pump for the deck wash. It had been submerged and refused to start. That was a low priority, and later I dismantled it and cleaned the commutator and brushes. It then came straight to life and pumped seawater through the deck gland, as though nothing had happened.

The dedicated windlass battery had not been submerged, and the windlass worked fine. Some spare mooring ropes, stowed below, were saturated and were dragged on deck, where the Florida sun soon dried them out.

The water pressure pump also started up drawing water from the two tanks to pressurize the system and I immediately spotted the reason for the flooding—a pipe had blown out of its connector. These were compression fittings held together with a screw-on plastic cap. I repaired the joint and the system pressurized normally from the pump. That old system definitely had to go!

I was on my own all this time, and the effort took two full days, but after a third oil change in the machinery, and with all other systems running again, I felt I had it all back to normal, after a very very close call.


I don't know how many years this episode has taken off my life, but the question now was: how to prevent it ever happening again? There was no guarantee against another pipe failure, or me forgetting to switch off the shore water again—although I think this highly unlikely, after what I had been through. It had been indelibly impressed in my brain.

The obvious thing, suggested by several well-meaning sailing mates, was not to use a shore-water supply at all and draw from the tanks, refilling them as needed. This would prevent a recurrence, but the same might be said about a shore electrical connection, which everyone uses without a second thought for battery charging, etc., but which has been the cause of many a boat fire.

My wife and I very much liked all the advantages of a shore water supply when we came to stay on the boat for weekends. So it was just a question of how to make it as fail-safe, and as idiot-proof, (that would be for me), as possible. The first obvious thing was to re-plumb the whole boat with new pipes and modern connectors.

Pipe-connectorNew pipeworkI found a suitable system at my local hardware store. I bought two 100’ foot coils of 1/2” inch 160-PSI PEX Pipe, one coil red for hot water, the other blue for cold. I pulled this new piping throughout the boat by taping it securely to the old pipes and hauling it through. I also re-routed much of it more directly, so I could inspect it easily and get to the connections. I then bought numerous connectors which I thought I might need, elbows, tees, splices, etc. They are made by Shark Bite and guaranteed not to leak or blow out of the pipe up to 100 psi. They are also easy to connect without special tools. The pipe is simply pushed into the connector and automatically locked by a barbed ring clamp and sealed with an internal O ring.

It took four days to completely re-pipe the whole water system and I was quite pleased with the installation, looking very professional with twin colors side by side and nice new connectors.

Now I had to decide how to somehow close off the water supply, automatically, in the event of another failure, however remote.

Shut-off valveI found an automatic shut-off valve on the web  It was a 12-volt solenoid valve that is normally open by default but closes when voltage is applied. I connected it to the water inlet directly after the pressure inlet and wired it to the boat's bilge float. When the float is activated by rising water it activates the valve, which closes and stops any more shore water entering.

LatchingrelayI thought that was all I needed, but upon testing II soon realized that when the bilge is emptied and the float switched itself off, the power to the solenoid switched off as well, and the solenoid reopens, allowing pressurized water to flow in again, and the cycle repeats continuously. After consultation with an electrician friend, I bought what is called a “latching relay.” This is a relay which, when the primary activating current switches off from the bilge float switch the relay stays on, maintaining power to the solenoid and keeping it shut. The relay opens only when an ‘unlatch’ current is applied. The latching relay is Part # 785XBXCD-12D from Zoro.com. This relay solved the problem, has worked flawlessly so far, (but I still disconnect the pipe at the shore when I leave the boat…) Later I incorporated a bell that rings when the system is activated. In other words, I now have a high-water bilge alarm. I also fitted a secondary safety shut-off valve on the end of the water pipe, so I can physically also shut off the water from the shore, and at the boat.

Just for interest I made a rough estimate of how much water had flooded into Britannia’s hull. It was quite a complicated geometric volume calculation, because the bilge was not uniform in shape, but it was certainly an eye-opener. I estimated that some 700 gallons had flooded in. One gallon of water weighs 8.34lbs, so the total Docksideweight of water was just under three tons! No wonder the old gal’ went down so far on her marks.

Seeing your boat full of water is frightening, even if you are tied to a dock. Without a doubt, if I had not returned and caught it when I did, the boat would have eventually gone down. The dockmaster later told me he had seen two unattended boats sink in this way.

Feeling quite satisfied with myself after installing my fail-safe system, I decided to find out how many boats used shore water supply in the marina. Out of a total of 20 boats that I could see with direct shore-water hoses connected, I spoke to the owners of twelve. I asked if they had any safety system, in case of an internal pipe failure while they were away from their boat. Amazingly absolutely none did, and had not even thought about it! They all said they relied entirely upon remembering to switch the water off when they left. That’s what I thought…I sure hope they read this story.