M35 Cooling Water Intake Strainer / Flow Rate

[rmbrown]

I'm replacing my thru hulls and valves with series 93 forespar parts.  They are being great to work with and are helping me put together what I need from thru-hull to hose barb.  That's pretty straight forward everywhere but on the cooling water intake where there is a strainer involved. 

I'm considering replacing my cooling water strainer with forespar's while I'm in here but there's no flow rate marked on mine.  Theirs is 40 gpm and, give it's size, is, I'm guessing way more than mine.

Was their a standard one used in our setup?  All I have on mine for markings is that it's 1/2" NPT and not for use with alcohol.

[KWKloeber]

Mike

Pictures?

The flanged sea cocks fit your thru hulls? 

kk

[rmbrown]

Here's what I have now...  I intended to replace my thru hull along with the valve but the shape and size of the flush "mushroom" isn't the same.  Forespar tells me that they can make the valves with a thread on the bottom to match the old thru hulls.  They aren't flanged in the traditional sense... no thru bolts... but they have a wide base to support them from failing due to rocking to one side and, according to Maine Sail's video test, they are plenty strong in shear.

https://www.youtube.com/watch?v=-tzB3IiImpo

[Fred Koehlmann]

Hi Mike,

Out C34 had the Marlon strainer: http://www.forespar.com/product589.html

Works well, easy to clean with the basket. I did have to get a new lid, 'cause it got screwed down too tight once.
It can easily be mounted, so that it's in a convenient location.

[Noah]

Mike I had some more questions over on thru hull thread.

[rmbrown]

Fred, I did get that strainer.  Definitely improved my potential water flow!

The straight pipe thread fittings for the hose that screw into bottom and side I taped with three layers of teflon tape but they screw in all the way to the bottom of the strainer.  There's no washer or seal there that I could see, making me wonder if I could be introducing air there.  Any thoughts on how to seal those fittings to the strainer itself?

[KWKloeber]

 I must rant about this once again.

Never EVER use PVC fittings on below the waterline hoses. ESPECIALLY schedule 40 PVC. 
Catalina was (and still is) notorious for using PVC where it never should've been used, and for using  mismatched threads (mixing NPT and NPS).

Use Forespar NPS fittings where appropriate, and glass reinforced nylon or glass reinforced poly NPT fittings  where appropriate to use them.  Although bronze and PT is preferred, it's very difficult to find a decent bronze fittings in the sizes that we need. Typically you can find them larger (e.g., 1-1/2")  but not in smaller sizes. A good survey or will bounce that install and make you change to proper fittings.

kk

[rmbrown]

Not sure what I said to imply I used PVC fittings, but I know better... mostly from studying here!

They are fittings from defender that are the correct size and thread shape... but are straight pipe threads rather than tapered so, like a garden hose, they just screw in... but no washer inside.  I watched Randy's Forespar video after posting and he said to use teflon tape or some other quality compound on the threads.  Maybe I'll just go thicker with the tape or research for the appropriate compound/sealant.

I tested for air leaks by both sucking and blowing through on port while blocking the other and both the vacuum and pressure held as long as my lungs.  Probabably it's fine and I'm just being paranoid.

On a related note, I filled the system with fresh water through the strainer until the level stopped rising, then closed the seacock and filled it to the top.  I pushed the lid on and squished out a little water but there's still air under that domed lid.  I suppose this is normal since the outlet is on the side and nothing's going to force that air out of there.  Am I missing something?

[rmbrown]

In face, re the PVC, I just removed every thru hull in my boat and replaced with Forespar Series 93 thru hull / valve combos in the correct configurations thanks to Randy... the ones I removed had plenty of scary PVC parts in them if anyone wants them. ;)

[KWKloeber]

 Mike, I'm looking at what "appear" to be white schedule 40 PVC fittings.  Would you share a link or defender p/ns of the strainer and fittings?

k

[rmbrown]

Ah, yes... But it's Fred's pic!

[KWKloeber]

Mike,


Do you have a name, mfgr, or part info on the strainer hose fittings that you found? 

Thx
kk

[rmbrown]

http://www.forespar.com/product589.html

I'm still a bit confused about mounting though... the instructions said to mount at least 12" above waterline, no doubt for liability reasons.  My mechanic says just below waterline otherwise a tiny leak results in an air bubble in the line that will stop water flow (as it did on first startup after installation).

[KWKloeber]

Mike,


Yes I see the strainer. But what I was talking about is you said you had found the hose fittings, I believe you said from defender or somewhere? Do you have a link to those.

[rmbrown]

http://search.defender.com/?expression=502935112034&x=7&y=8