raw water screen

[Ken Juul]

Teh jelly fish or "nettles" as they are know in the Chesapeake are really bad this year.  I have to clean my strainer for the A/C 3 or 4 times a day.  Not too bad a job except for the one at 3am

Thinking about adding an external screen like shown in the link.  

http://www.buckalgonquin.com/Buck_Algonquin/Pages/Underwater%20Hardware/Page_19.pdf

Do you think this will work or just move the location of the blockage?  The thought is the larger intake grill area will cause less draw than the intake itself so the nettles won't get sucked in.

[Jim Price]

Just my opinion, looks like something that would require more attachment holes in outer hull (not so good) unless glassed in and that would have it's own set of issues.  

How would you clean at 3 AM once it gets clogged?   Mighty dark under the hull - would rather mess with the strainer inside the boat.  

Seriously, I routed my AC cooling lines through the center compartment of the bilge where my bilge pump is located.  Also have my refrigerator filter there.  Reason was that I can access both easily; if they leak they are close to the pump; and when I need to clean, I can actually open strainer in the bilge (with seacock open)  and use inflow pressure to quickly clean the screen and the pump gets to do a little cycle time.  I don't always leave seacock open to do this but mess is still contained in bilge.  I am in fresh water so no "jelly bellies" but lots of good old organic slime.

[Stu Jackson]

Ken

I agree with Jim.  The external screen idea has been discussed many years ago related, then, to the raw water intake for the engine.  I think it was in one of the earliest Tech Notes.  The theory is this:  if you put anything outside the hull, you preclude the ability to push a wooden dowel, or even a long screwdriver, through the thru hull to push the critters out.  Many skippers have installed Ts in their RW intakes.  If a hose is extended from the T to a point above the waterline, (or if one simply opens the T just above the thru hull, and can accommodate the squirting water inside the boat for a short period of time, one could leave the thru hull open, and push a dowel through to clear the obstruction at the thru hull.  With a scoop or screen outside, this "dowel clean" idea wouldn't work.

I would guess that this is just as applicable to your AC intake.

I recommend considering whatever it is you can do to obtain access to the  AC thru hull to clean it out from inside, rather than creating yet another source of blockage that you cannot access easily from inside.

Also saves you some $$ and a haulout!  

[Ron Hill]

Guys : The Mainsheet reference to a screen on the outside of the raw water inlet was mine.  
I installed my small round Perko strainer on the outside by using spots of silicone caulk on 4 sides. That was done so I  could use a wooden dowel to poke out a stoppage.  Figured that if I ever had to poke it off it would only be a $5 loss.   Did that back in 1998 and have never had to poke off that strainer.  Can't tell you how many times it kept the strainer from filling with sea grass, hydrilla or junk, but before I installed it I was poking out stuff/junk every other year.  It's had no effect on engine cooling.  If you decide to install one just remember to use bottom paint on the INSIDE of the strainer, before installing.

Now to the matter of sea nettles/jelly fish.  That strainer isn't fine enough to stop them.  Any screen that fine would probably get clogged all the time.  I wrote a tip in the Mainsheet that when you get a stoppage in a line that is hard to get to, blow it out with the dinghy pump.   Most dink pumps have an adapter to fit most hoses.  We used a dink pump to unclog a fellow C34 owners AIR CONDITIONING HOSE !!!

Good stuff in those old Mainsheet Tech notes.  

[Ken Juul]

The External strainer was suggested by a couple different marinas/stores.  I kind of felt they were more after the sale than to solve the problem.  Thanks for the input, you verified what I was thinking.   Don't mind the 3am cleaning that much, it's just disturbing if I have guests on board.