SailNet Community banner
1 - 1 of 1 Posts

Super Moderator
Farr 11.6 (Farr 38)
10,540 Posts

I have wrestled with this since I bought my boat, It has always had an perforated clamshell on the engine intake. i will start by saying that as long as I have been around boats, the general approach is to put clamshells on intakes so that large debris does not get sucked into the intake hoses The logic has been that the clamshell is the course filter and the inline strainer is the fine filter. I basically agree with that concept.

But like you, I have had a real problem with barnacles clogging the clamshell. I have a diver clean Synergy's bottom on a regular basis during the warmer months. The diver makes a diligent effort to clean out the barnacles when the bottom is being cleaned. But that very cleaning process leaves enough debris to clog the intake hose at the thru-hull. I have made a rig that allows me to easily remove the intake hose from the raw water pump, and hook up a garden hose to the intake hose and flush the strainer and raw water line back through the strainer, seacock, and clamshell. I do that every time that the bottom has been cleaned and the combination of the cleaning and back-flushing it seems to work fine.

But it would be nice if i could minimally eliminate the back-flushing. I have never seen a fitting like this (below), but I really like it since it would allow you to apply anti-fouling paint inside the course strainer, and would allow the diver to clean in there more easily. Its not clear whether that particular version would lend itself to be opened by a diver, but in theory, it would be pretty easy to build or adapt that so a diver could operate it from below the boat. (perhaps with a simple pivoting gate that would lock it closed.)
Of course that does not eliminate the diver issue, or the problem clearing it without a diver. In an ideal world there ight be a fitting like this that could be operated from the interior of the boat, or which had a internal arm that could be turned within the housing to clear the enclosed interior of the housing. I can image how I would engineer that, but cannot image anyone actually buidling such a thing.

1 - 1 of 1 Posts