do you need a strainer

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I think the issue is size of the demand versus the size of the intake.

In other words...what is the flow like being sucked in.

I have 1 inch demands on 1.5 intakes with no external screens.

Occasionally I clean the air conditioner internal basket, but the genset I hadn't cleaned in 3 years (not very heavy use) and the main only 2 times in 3 years of ICW travel back and forth to Fla.

I can only attest to flow...because of my travels...the conditions are varied but may never hit some real problem situations like Chesapeake jellies in the summer.
 
caltexflanc said:
They may have external strainers, which are becoming more common. What did your surveyor have to say about it when you were buying your boat?
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Nothing that I recall, but he turned out to be not so great a surveyor....not terrible but he didn't really spend enough time for a boat that size and complexity. I might re read the survey to see if there is any mention of this and/or simply call him up to see how typical or untypical this boats configuration in that regard may be.

As to the other members comments about leaving the keys on the seacock...there are no keys (except to get in the salon or helm room)

As an aside, the engines can be started and stopped from three different locations on the boat....in the engine room (over 6 foot headroom, full beam), at the inside helm or on the flybridge.

FWIW, the procedure is to first turn on the ignition circuit breakers, then "engines on" toggle, and then momentary "start" toggle for inside helm and flybridge.

Procedure in engine room is ignition circuit breakers on (engine room has it's own breakers for that purpose) , then press momentary "start" button for each.

Also a button for "prime" but have never used it as the engines start in the same instant the start button is pushed. (aprox 280 hours since block up overhauls)

In contrast my Onan 20K generators, that have aprox 1300 and 1500 hours are much harder to start. Require a few seconds of preheat plus 2 or 3 tries at the start switch. But run perfectly after they finally start. I wonder if that is typical of those and why the difference compared to the Detroit monster prime movers..2 cycle diesel vs 4 cycle ?
 
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Most of the large sportfishing boats these days do not have internal basket strainers. They rely upon screens on the hull exterior. I think a lot has to do with the space the strainers would take up in the engine room due to the large size of the inlet piping.

If I had external screens and no basket strainers inside I wouldn't be in a hurry to add basket strainers until I had proved that I needed them. They are another piece in your engine room that will demand your attention as if you don't have enough things like that already and consume space you probably don't have.

I have been polling clients and yards about there experiences for quite a few years and looked at quite a few perforated and slotted strainers. Haven't heard complaints about either. What I have noticed is lots of big oysters, barnacles and other wildlife in slotted strainers and not much in perforated ones. I think they drift into the slotted ones and stay and just drift by the perforated ones. I have seen quite a few basket strainers that were in need of service.

This is one of those discussions that merits the old cliché "it all depends" which will work best for you...
 
Growth on the Chesapeake Bay was bad last year. A friend of mine with a 41' SeaRay had an engine overheat due to his perforated strainer clogging up with what looked like a big mat of moss. My strainer is easy to get to and clean if required. I agree that "it all depends on which will work best for you"
 
Caladan said:
Nothing that I recall, but he turned out to be not so great a surveyor....not terrible but he didn't really spend enough time for a boat that size and complexity. I might re read the survey to see if there is any mention of this and/or simply call him up to see how typical or untypical this boats configuration in that regard may be.

As to the other members comments about leaving the keys on the seacock...there are no keys (except to get in the salon or helm room)

As an aside, the engines can be started and stopped from three different locations on the boat....in the engine room (over 6 foot headroom, full beam), at the inside helm or on the flybridge.

FWIW, the procedure is to first turn on the ignition circuit breakers, then "engines on" toggle, and then momentary "start" toggle for inside helm and flybridge.

Procedure in engine room is ignition circuit breakers on (engine room has it's own breakers for that purpose) , then press momentary "start" button for each.

Also a button for "prime" but have never used it as the engines start in the same instant the start button is pushed. (aprox 280 hours since block up overhauls)

In contrast my Onan 20K generators, that have aprox 1300 and 1500 hours are much harder to start. Require a few seconds of preheat plus 2 or 3 tries at the start switch. But run perfectly after they finally start. I wonder if that is typical of those and why the difference compared to the Detroit monster prime movers..2 cycle diesel vs 4 cycle ?
Click to expand...
the prime button might be to pre lube the engines before you start, i have been on a few boats that have that system,it is good to use if they havent been run for a while, or it could be to prime the fuel during a filter change. but if it is on the dash board it is for oil.i deliverd a few of the way back when they wer built in the old lazzar factory in saint pete florida
 
capt jerry said:
the prime button might be to pre lube the engines before you start,
Click to expand...
That sounds like a good feature to have but my 12v71 primer buttons are labeled "fuel prime".

Ironically the generator fuel primer buttons are labeled just "primer" but I know are also for fuel priming as I have used one of them for such.
 
All we have is a through hull flanged port. No grillwork or screens of any kind. Never had much to clean out of the strainer either. If nothing was to change I could go for 10 years w/o opening the lid.

Always had thoughts about getting a screened intake though.
 
do I need to spend the 300$ x 2 for sea strainer?

YES‼️
 
olesouth said:
....do I need to spend the 300$ x 2 for sea strainer I am wounder how many people have them
Click to expand...

I think it depends on the waters you boat in. How likely is it that your engine intake(s) will suck in something potentially damaging?

In this area eelgrass grows all over the place in water 30 feet or less deep and one encounters individual strands to dense mats of it everywhere, particularly in the current lines and tide rips.

Eelgrass can easily thread its way past a lot of the external grill or perforated plate designs. Unless there is a sea strainer in the raw water line the strands can end up in the raw water pump where it has been known to clog the intake and output ports and even wrap itself tightly around the impeller shaft.

Our boat, which spent the first 25 years of its life in SFO Bay until we bought it in 1998 and trucked it north, did not have sea strainers on the raw water intakes. Perhaps they are not so necessary in the bay, delta, and Sacramento River, I don't know. But knowing what kind of debris is in the waters here, we had big sea strainers added to the intakes before the boat went back into the water after being offloaded from the truck.

It already had perforated bronze plates (cups, really) over each raw water intake in the bottom of the hull.

A friend once had eelgrass clog the entire hose run from the engine's raw water intake through-hull to the sea strainer. His boat does not have any sort of screen, grill, or perforated plate over the engine intake. It took him some two hours to remove all the grass from the hose. But the sea strainer prevented any of it from making it to the engine's raw water pump.
 
Marin,
I don't read anything in the above post that would support the need for intake screens. Yet you put them on straight away. I probably should follow suite. Didn't even think of it though. Had the seacock replaced too. Where's the grass around here?
 
Eric--- The exterior screens (perforated dished bronze plates in our case) were already installed over every intake through-hull on the boat when we bought it.

What we had the yard in Tacoma add before we launched the boat after trucking it up from California were the big bronze and glass Groco sea strainers in the engine room between the intake seacocks and the raw water pumps on the engines. The boat had not had these during the first 25 years of its life in SFO Bay.

There is eelgrass in the water all over the place in Bellingham Bay and in the islands. We had the boat out into the islands yesterday with friends from back east and dodged any number of big, floating mats of eelgrass. How it gets ripped out of the bottom I don't know but the mats (and individual strands) as well as free-floating kelp are an ever-present component of the trash lines along current breaks and tide rips.

We see this all the time farther south, too, when we use our trailer fishing boat for crabbing near Whidbey and Camano islands.

While the exterior perforated plates were already on the boat, our diesel shop told us that they do help prevent eelgrass strands from being sucked up into the sea strainers, sort of a "first line of defense" if you will. The advantage given by our diesel shop is that they have seen individual strands of eelgrass snake their way through a sea strainer and make it into the impeller chamber of a raw water pump. This may or may not cause a problem depending on how much grass works its way in there.

In the case of our friend that I described in the previous post, the sea strainer prevented the eelgrass from getting to the raw water pump itself. But because he has no exterior screen or plate at all, it was easy for the suction from the 420 hp Cat in his boat to pull a lot of grass into the intake hose when he was running in shallow water or through grass mats and eventually it clogged the hose and sea strainer so tightly it was enough to cause his engine to suddenly and rapidly begin to overheat (at a rather inopportune moment).
 
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Given how bad our generator strainer has been filling up with eel grass and hydrilla this year, I think we may consider adding the external grates at next haul out. I was cleaning it about once an hour this past weekend. The AC and main engine intakes are deeper, located close to the keel, and thus far we have not had the same issue with those systems. (knock on wood)
 
My ocean alexander has a large manifold that has a 6" intake and 7 outlets (of various sizes). All outlets go to groco's and I am being still amused at what I find in them.

Usually it's green scum algae, whoever name this "Clear Lake" was clearly a moron, but I have gotten some jelly fish, and yesterday I found 4 - 1" long shrimp. With that 6" inlet, I cant wait till I catch that 3' tarpon than patrols under the dock. :)

If I was at sea, I might wonder about the need, but here dockside it's very clear the screens are a must.
 
Weather plays into this as in freezing Temps. Freezing the water within the strainer can break the housing etc etc point being as usual there is no simple answer. Er Temps can be much colder than water Temps. Most strainers located bellow the water line. Gate valves instead of ball etc etc
Random thoughts. I have dewatered a fewboats suffering from such after the warming
 
OFB,
Nice to see you posting.
Looks like you've anchored the OFB and are going somewhere in a Livingston.
Thanks for sharing some travels.
Eric
 
We seem to loose at least one boat a season in our marina due to cracked sea strainers and failure to properly winterize. One that went down this past winter the owner claimed he had a bilge heater. Putting aside that wisdom when the power goes out, when asked where the heater was located he said in the cabin. :eek::banghead:
 
manyboats said:
OFB,
Nice to see you posting.
Looks like you've anchored the OFB and are going somewhere in a Livingston.
Thanks for sharing some travels.
Eric
Click to expand...


Eric
Not to hijack the thread, but I was checking your profile- which led me into checking out Concrete Alaska. WOW! What a beautiful town! The churches, the dam. Henry Thompson Bridge.
I'm done :). What a great place to live.


1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
It's actually Concrete, Washington. So named because of the aggregate company that used to located there.
 
Sorry.. Meant Washington. Was amazed by the architecture and building styles. Would love to visit the town someday :).


1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
Forkliftt said:
Sorry.. Meant Washington. Was amazed by the architecture and building styles. Would love to visit the town someday :).
1983 Present 42 Sundeck
Twin Lehman 135's
✌️
Click to expand...

Well, there's not much too it anymore. Basically one main street parallel to the highway and some residential streets. But there are some neat buildings and the two reservoirs behind dams up behind the town, Lakes Shannon and Baker, are nice to visit, camp and fish on. Some of the big aggregate silos are still next to the highway and they have a little general aviation airstrip across the river.
 
Thanks for things to look for :). Wikipedia lists a few "first" engineering accomplishments in the past (Lower Baker Dam and the Henry Thompson Bridge). I think it would be a great place to visit, and with a population of ~ 740...
It can't be too "touristy" I hope:) !!


1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
Forkliftt;359551 It can't be too "touristy" I hope:) !![/quote said:
No. Tourists don't even see it as they whiz by on their drive up the Skagit River over the North Cascade Highway (Highway 20) through the mountains to eastern Washington. I've lived here for 36 years and driven past Concrete hundreds of times but the first time I ever bothered to drive into it was earlier this year on our way back from looking for eagles up the river (there weren't any, the salmon had all spawned, died, and been eaten and the eagles were all back down in the Skagit delta). On a whim we drove a block over onto the main street of Concrete just to see what it looked like. Not much there, really, but we did stumble across a really cool logging arch in a fellow's yard. Stopped and took some photos of it and then headed home.
Click to expand...
 
Small world... Hopefully Eric will pitch in with some of his experiences.


1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
Marin thanks for filling in for me. My computer is in the shop. I'm pretending to be Chris on hers but don't have access to my pics.

Steve,
Glad you like our digs. Coming from SE AK perhaps we picked out a place that resembles the north country. I say sometimes that many of the people here resemble the people of Thorne Bay more than the people of Thorne Bay. Similarities are surprising but it's very different.

PM me for a phone # and let me know when you're dropping by.
 
Eric,
That would be great. I will do. We have locked in a few "to do"s already. Patricia and I are looking forward to getting up there:).


1983 Present 42 Sundeck
Twin Lehman 135's
✌️
 
Funny thing is...


On boats prior to our Tolly we had viewable in bilge strainers/filters and we sometimes (fairly often) needed to clear them out of slime/small-debris for continued good water flow.


But!! On our Tolly we have no strainers... just really good close tolerance, large "strand" screens as engine cooling water pickups on boat bottom. Inside SF Delta we are often in shoal waters that have willowy sea weeds at surface and under surface. We have not had engine overheat in seven years of being in Delta waters and I often go under boat with mask on... never seen anything in the water pickups. When changing raw water impellers no problem-stuff found either.


Soooo... I must ask... are view-screen strainers/filters inside boat between under-hull water pickup and engine really necessary??
 
Art said:
Funny thing is...


On boats prior to our Tolly we had viewable in bilge strainers/filters and we sometimes (fairly often) needed to clear them out of slime/small-debris for continued good water flow.


But!! On our Tolly we have no strainers... just really good close tolerance, large "strand" screens as engine cooling water pickups on boat bottom. Inside SF Delta we are often in shoal waters that have willowy sea weeds at surface and under surface. We have not had engine overheat in seven years of being in Delta waters and I often go under boat with mask on... never seen anything in the water pickups. When changing raw water impellers no problem-stuff found either.


Soooo... I must ask... are view-screen strainers/filters inside boat between under-hull water pickup and engine really necessary??
Click to expand...


You should buy a Lottie ticket ;) Cleaned out my strainer last week 4 little fish about 2 inches long still alive a big hand full of 1/4 inch ribbon grass and 12 inches of braid fishing line it took 2 minutes to clean the strainer and wonder what would have happened if any one of those 5 things go into my water pump :confused:
 
Art- Strainers are important here. We have eelgrass that has a way of working it's way past through-hull screens and can even find its way through a big sea strainer and into a raw water pump where it can screw things up.

Our boat, which spent the first 25 years of its life in SFO Bay and the delta and river did not have sea steainers when we acquired it. We had them installed immediately upon the boat's arrival here. So perhaps they are not as important to have down there as they are up here.
 
Art said:
Soooo... I must ask... are view-screen strainers/filters inside boat between under-hull water pickup and engine really necessary??
Click to expand...
Simple answer is that the external screen prevents most of the junk, but whatever goes through goes until it hangs up somewhere else. The internal strainer basket often holds some solids that fell out do to gravity. Have both on my charter boat, and often find some hard bits in the bottom of the strainer at the end of the season. While they likely go right on through, I'm happy that there not getting between the pump impeller and the housing. While the internal one isn't absolutely necessary, I certainly wouldn't remove it if you were adding the pin hole style external one. Now have both on my trawler.

Ted
 
gaston said:
You should buy a Lottie ticket ;) Cleaned out my strainer last week 4 little fish about 2 inches long still alive a big hand full of 1/4 inch ribbon grass and 12 inches of braid fishing line it took 2 minutes to clean the strainer and wonder what would have happened if any one of those 5 things go into my water pump :confused:
Click to expand...

Seems you must have wide open hole in bottom for water draw. We don't. Our water hole has cover of many 1/4" slat openings about 5" long. Total width of this slated external strainer is about 4". What you found in your inside strainer would get past our external strainer.
 
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