Aligning strainer with fixed flanged seacock.

[preserved_killick]

I'm about to install a nice flanged seacock to replace a ball valve for my engine water intake. One thing that occurred to me that might be a problem is aligning the strainer. If the seacock is fixed to the hull (bolted), then what happens if you bottom out the threads on the strainer/through-hull and the strainer is facing the wrong way?

I'm talking about a strainer like this:



Currently the setup is strainer, through-hull nut, ball valve and then hose.

-jeff

[Maine Sail]

You might consider using the Groco round style with holes rather than slots or none at all. Hamilton has one that opens which is a very good idea.

These have much less propensity to pick up eel grass:

http://store.hamiltonmarine.com/browse. ... 20121.html


In the last two days I have seen two people in the yard, one with a Gulfstar and one with a Sabre 38 removing the external, screwed on slotted strainers, and cleaning mussels from inside the thru-hull. With a fixed slotted strainer, integral to the thru-hull, you do not have that option even on the hard.

On another note I very much dislike slotted strainers. They are often installed the wrong way, which can potentially hydrolock your engine, slots should face aft on a sailboat, and they tend to pick up floating eel grass which is nearly impossible to clean out if you can't open it. Two hours diving with a coat hanger is not my idea of fun on a "vacation" been there, done that.

Eel grass is bad stuff and will get in there. Motor through some of this vertical floating stuff and you'd really better have a way to get it out once in..



Since about the late 90's I have been over sizing my intakes and using large Perko bronze sea strainers and going sans external strainer. I also have a snake that I can ream out my intake with, from inside the vessel. Rig your intake hose so that when disconnected from the sea strainer it is above the static waterline and you can then hold it and ream anything back out into the ocean. If you have an external strainer you can't do this..

Just some thoughts from someone who has banged his head on the underside of a hull a few to many times..

[Tim]

I don't use an external strainer. A big bronze internal strainer is the way to go in my opinion.

[preserved_killick]

Tim,

No External Strainer? Is this common? In my limited experience I've not seen this in practice. That would make the seacock install much easier.

Gosh, is relying on just the one internal strainer enough? What if..a plastic bag gets sucked in? Would it get trapped in the hose?

-jeff

[Rachel]

I'm not an expert, but I can say it's not just Tim. The thought is that if the external strainer clogs you have no way to get to it except to go over the side; whereas you can access the internal strainer.

I took the external strainer off my Alberg 30 (the round type with round holes) and instead mounted a bronze internal strainer (basket in glass type). I've been in touch with the fellow who bought the boat from me, and he has not mentioned any problems. (It's on the Chesapeake.) Not that one anecdote is data, but I do believe a number of people have their boats set up this way.

If I were going to have an external strainer, I think it might be nice to have the type that swings down so you can clean it out (but you still have to be in the water or have your boat on the hard).

Rachel

[Tim]

One must do that with which they're comfortable. I'm not telling you not to use an external strainer--just that I don't use one. Here is my reasoning; draw your own conclusions.

If I'm going to have a clog, I'd like it where I can get at it, not outside the boat. I think you see so many external strainers because original builders/outfitters are looking for the inexpensive and easy option rather than springing for the higher cost (and space requirements) of an excellent internal strainer. Given how miserably cramped sailboat engine rooms tend to be, it's easy enough--if indefensible--to see why some might not favor large, easily-accessible internal strainers, though this is shortsighted.

I just don't see what an external strainer does, other than clog inordinately and cause issues that are challenging to resolve. I don't much like swimming even in nice water; I'd certainly prefer to avoid it at all costs in icy northern waters. All this being said, eliminating an external strainer means that a good internal strainer becomes critical. It should be mounted where it's easy to get to and inspect and service.

Any clog is inconvenient, but if something gets sucked into your hose, at least you can close the seacock, remove the hose, and clear it out--or even throw in a new hose (everybody has spare lengths of hose on board, right?). If something clogged my intake, It'd be easy to clear the through hull from inside the boat if I removed the hose from inside, since there's no strainer on the outside.

I think those external strainers clog with mussels, little shrimp, and weed, not to mention layers of bottom paint over time. I check my internal strainer daily and clean when necessary--which, frankly, is almost never. More often, I clean it out just as a matter of course if there's even a small amount int here. I steer around floating seaweed and debris whenever possible. Two years ago, I never opened the strainer all season, and this is all that was in it at haulout. Now, I think this was the first time I'd never had to open it all season, but still.

[Tim]

By the way, when I talk about an internal strainer, this is what I mean. This is mine, and I wouldn't use anything less than this. Note also the easy access, which is just as critical, I think.

[preserved_killick]

Thanks Tim. Your argument makes sense to me.

I've just installed a new internal water strainer, but went with the Vetus 330:


Plastic, not bronze. I don't have the room (width) for a Groco or Perko bronze strainer due to the hose attachment setup. I bought the Vetus and the Groco, the Vetus, even though it is plastic it seemed much more robust and simple. Just one gasket to maintain and a much bigger filter area. It is mounted well above the waterline and is easy to get to.

I like the idea of the flanged seacock instead of the ball valve so I'll likely do this, but it may need to wait until the fall. The boat's getting picked up and launched in a few days.

Tim, a question on your water lock muffler install. I see you've got it below the engine. Is the muffler supported, bolted to the side of the hull? I'd love to move mine to that location. Right now it is in the way of getting to my stuffing box.

I've done a number of improvements this spring, most of them as a result of suggestions from this board. I hope to get some pictures today.

-jeff

[Maine Sail]

By the way, when I talk about an internal strainer, this is what I mean. This is mine, and I wouldn't use anything less than this. Note also the easy access, which is just as critical, I think.

Also note that Tim is using the correct type of sweeping elbow not a standard 90 with a threaded hose barb. The bronze sweep ell's allow the junk to make it to the strainer with less restrictions.


This = restrictions and clogs at the ell


This = less restrictions at the ell

[preserved_killick]

Thanks Maine Sail,

I did notice that sweeping elbow. I find it amazing how much room he has there. In my Alberg I really need to use the Vetus shown since it has the direct down fittings. I just don't have the room side to side unless I mount the strainer in a crazy spot difficult to reach.

-jeff

[Tim]

Tim, a question on your water lock muffler install. I see you've got it below the engine. Is the muffler supported, bolted to the side of the hull? I'd love to move mine to that location. Right now it is in the way of getting to my stuffing box.

In my boat, the bilge is shallow beneath the engine--no deep sump. So the muffler you see is actually sitting on the bottom of the bilge.

(step way back in time for this photo...)


Here's a way to do it in a boat like yours with a deep bilge. Build a removable platform on which the muffler can rest. In this boat, I glassed FRP angles to the hull, then screwed a FRP platform to the glassed-in angles, and screwed the muffler to the platform. It's all removable (not necessarily regularly, but possible) for access to the bilge should it be necessary.

For a plastic Vetus, you could add some cleats to hold it in place, and perhaps a strap.