It was another spectacular summer day as we released the dock lines and once again escaped life ashore, the trusty diesel humming beneath our feet. The weather forecast promised sunshine and moderate winds. My wife and I were away uncharacteristically late, something that seldom occurred on our boat. Friends were in a beautiful anchorage ten miles away, cocktails and dinner awaiting our arrival. We wanted to be there! Light wind rippled the clear blue water as we passed the breakwater, a plethora of boats skittering about like water bugs on a lake. A busy afternoon at the marina with a promise of another relaxing weekend on the water.
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Lucky it didn’t put you in a tight spot! Thanks for sharing the low-flow sensor. I added that to my list of future improvements.
I’ve installed the same alarm. It will not only alert you to a clogged intake, any obstruction to flow such as a corroded mixing elbow or a failed impeller will set off the alarm. It may even warn you if you forgot to open the seacock:) Better to know of problems immediately, rather than waiting for the engine to warn that it’s about to warp it’s head.
I have used this method for years to clear air conditioning pump inlets. I have four AC units with three through hulls supplying raw water flow for them. With the sea cock closed, I remove the bowl of the strainer, empty it and clean it of the choking debris picked up in the water where our boat is berthed, and reassemble the strainer. With the sea cock still closed, I disconnect the inlet line at a convenient location where I can use an attachment that came with the pump to join the pump outlet to the dissimilar inlet line from the through hull, with pressure applied to the pump before opening the sea cock, and then with vigorous pumping by my wife when I open the sea cock, we listen for bubbles under the boat. The pump is elevated above the level of the through hull, limiting the back flow of water to the pump. Sometimes I must take over the foot pumping. After reassembling the lines and starting the air conditioner raw water pump, if I do not get the expected water flow, I loosen three of the screws on the front of the pump until all air is expelled and a slight spray of raw water occurs. Tightening the screws on the face of the pump ends the process, except for cleaning up any water left in the bilge.
Hello Gary. I just replaced a hose system on a Sabre 386 today, extending the raw water intake hose from the through hull to the raw water strainer into a loop. It’s hard wall and when removed from the strainer, springs into a vertical position. The top of the hose is then above the waterline. The top batten of the main sail is the perfect fit, width and length, to now poke down the hose and clear any plug once the through hull valve is opened. The hose and foot pump would also work without letting water into the boat. The trick is the hard wall hose, it’s ridged enough that it doesn’t have to be held up while working with it. Thanks for the comment.
Could you comment on the installation of the aqualarm flow detector? I could not find anything in YouTube
My apologies for not responding sooner Luis. The installation is fairly simple. Mine is placed between the through-hull and the raw water strainer, it’s the only place it would fit. But it could go anywhere from through-hull to raw water pump. The challenge will be water flow, establishing that you have enough that the alarm will not trigger at idle. With my small Beta 20 there simply wasn’t enough water flow so I installed a on-off switch on the alarm panel. Once I’m up past 1,600 rpm I flip the switch. When I throttle back (coming into port) the alarm sounds, I turn the system off. I now have confirmation that it works. I also chose the dual alarm system from AquaFlow, it also has a heat sensor on the exhaust hose. It’s the always-on back-up. I believe the AquaFlow web site has that information as well.
Great article and good thinking. I will also prepare a kit for “just such an emergency.” Also impressed that you did not allow a pesky mechanical malfunction to interfere with cocktails and dinner!
SAIL boat first, pesky engine (that I really admire for reliability) second! I’ve had that second through-hull for a year now and feel far more assured that I have a back-up should something plug up the primary source of water. Thanks for the comment.