Raw Water Intake

Skipper Dick · Post by **Skipper Dick** » Nov 12th, '10, 08:41

I'm finally getting around to replacing my raw water intake system. It currently consists of two 1 1/4 inch thru hull scoops to gate valves then through Perko 493/500 strainers then to the Mercruiser Horizon 300 hp engines. Besides being ugly and taking up too much room, the gate valves are inoperative now and I can't even open or close them any more.

So I am going to start from scratch with a new thru hull, backing plate and ball valve flange mounted to the new backing plate with silicon bronze bolts. This will also give me an oportunity to replace gaskets on the strainer and clean up the plastic tubes so you can see through them.

The port thru hull scoop has a missing grate, so it needs replacing. My thoughts are to just replace them both with mushroom thru hulls instead of scoops. I've researched the engine manual to see if it specifies a scoop and all it says is that the thru hull system should be no less than 1 1/4 inch with a strainer. Going with mushroom thru hulls would simplify the project for sure.

My question is: is there any good reason why I can't get away with this? I don't live in an area where sea grass is a problem.

Dick

In Memory of Vicroy · Post by **In Memory of Vicroy** » Nov 12th, '10, 09:47

Dick - if you are going to replace the thru hulls anyway, why not go to inch and a half or bigger so if you decide to go diesel in the future you will be set?.....you can choke them down to inch and a quarter for now, and use the rest of your existing stuff.

UV

Whaler1777 · Post by **Whaler1777** » Nov 12th, '10, 11:41

I would go with what Vis said on increasing the diameter, I would also get rid of the internal strainers and go with a pair of externals to free up some wasted space in the hull...

AndreF · Post by **AndreF** » Nov 12th, '10, 14:04

For Perko parts:

http://www.cgedwards.com/Perko/pko305-11.html

gplume · Post by **gplume** » Nov 12th, '10, 21:19

I did my whole system last year from the stock B 31 set up...similar to waht you described. I went to the the external stainers as recomended on this site by Capt. Patrick and removed the original strainers. One season down and no probelm though I do have a little growth on the stainer. !.5 " groco lever seacocks, with side ports to crash valves. Up to a T and into the engine inlet hose. I can open up from the line through the T and punch out any obstructions (like barbacles). I have some pix somewhare...will look and post later. The whle set up is much better than stock...I am please with how it came out.

scot · Post by **scot** » Nov 12th, '10, 22:03

Ditto what these guys are saying, go back with 1 1/2" fittings. The cost is nearly identical and could save you grief down the road, also the system will flow better and not be as sensive to marine growth. The farther you go toward the engines with the 1 1/2" dia, the better the system will flow.

Moving up to a 2" iinlet is a bit of a cost increase, and not needed for most common B31 diesel applications....plus 2" strainers are freakin huge!

coolair · Post by **coolair** » Nov 12th, '10, 22:12

how important is it to use the flanged valves? and are the original scoops good enough or do you need the new style groco ones if you remove the big strainger?

Whaler1777 · Post by **Whaler1777** » Nov 12th, '10, 23:03

The original scoops are more prone to barnacle/other sea life growth than the larger groco strainers... Groco even has a model with an access door so you can clean behind the screen... You don't have to go with the flanged valves but I think that the in-line valves have a slightly different thread than the thru hulls (npt I think) I initially bought the in-line 2" valves but just went to the flanged to save even more space in the hull...

Skipper Dick · Post by **Skipper Dick** » Nov 13th, '10, 10:03

coolair wrote:how important is it to use the flanged valves? and are the original scoops good enough or do you need the new style groco ones if you remove the big strainger?

I decided to use the flanged seacocks to meet the current ABYC safety standard for a seacock installation and I want to eliminate the scoops because the mushroom thru hull is much simpler to install. There are no additional breeches in the hull for screws. I intent to remove the current scoops and fill in the screw holes. I can always eliminate the strainers for the hull mounted Groco strainers at a later date.

I keep this boat on a lift, so I really do not have to worry too much about growth on the bottom. Also, I could never justify re-powering with diesels in this boat. It's just not cost effective and affordable for the use it gets. If I did decide to go diesel, I think it would be better for me to just buy a boat with them already installed. About the only interchangable part of the running gear would be the struts.

Besides, if I get too carried away, I'll be exiled to the dock with the geckos and little land crabs.

randall · Post by **randall** » Nov 13th, '10, 10:14

one nice thing about the crash valves (besides the peace of mind) is how easy it becomes to run fresh water or antifreeze through the system. when i redid my raw water intakes i set up the plumbing so i could screw a pipe mounted in a spackle bucket directly into the system. makes it a piece of cake. give it some serious thought.

wlbsr · Post by **wlbsr** » Nov 13th, '10, 11:44

I went to the the external stainers as recomended on this site by Capt. Patrick and removed the original strainers.

can someone point me to these

scot · Post by **scot** » Nov 13th, '10, 14:07

Randall said:

one nice thing about the crash valves (besides the peace of mind) is how easy it becomes to run fresh water or antifreeze through the system. when i redid my raw water intakes i set up the plumbing so i could screw a pipe mounted in a spackle bucket directly into the system. makes it a piece of cake. give it some serious thought.

Ditto, put the crash pumps in while you have it all apart, Bertams don't have foam floatation. They will settle in nicely on the sea bed in short order with a decent sized leak.

I had one on my last boat and used it to flush after every run. Will have one on my current project as well. A marine engine's raw water pump can move 30-40, some over 50 gallons per MINUTE and are not subject to draining batteries.

Marlin · Post by **Marlin** » Nov 13th, '10, 18:36

Groco safety ball-type seacocks full flow SBV series,, have a quick release plug and offer a safety ball valve servicing adapter for winterizing, available from Lewis on east coast, dont assume the 1 1/2 thru hull fits all, the 330 hp new cummins require 2" intakes, wish I had heard about these seacocks before I tackled the crash valves i recently installed, lots of pieces parts and take up valuable realstate

bob lico · Post by **bob lico** » Nov 13th, '10, 21:46

marlin just put a bronze close nipple and two inch tee after sea-cock ,from there you can reduce tee and angle or devert to any place you have room to get your hands to to work valve handle.

Tony Meola · Post by **Tony Meola** » Nov 13th, '10, 23:06

Marlin

I have the two inch Groco's with the plug. After using it a few times for winterization, I would say that it is not a good crash pump option. It takes too long to pull the plug and put in the adapter. Plus if water is rushing in, just not going to happen. Put in a separate crash pump set up.

PeterPalmieri · Post by **PeterPalmieri** » Nov 14th, '10, 07:11

One of the things I need to upgrade on my boaat. It's a maze of piping and I believe my suyveyor said that the SW Intake system should be able to support 400lbs.

Sounds like this would be a good upgrade, since you guys are way ahead of is what your saying.....You normally turn off the sea cock to winterize the motor and run anti freeze. If done correctly this can also be used to pump water from the bilge?

randall · Post by **randall** » Nov 14th, '10, 08:56

thats it. on my boat it takes literally 2 seconds to shut down the saltwater and open the crash valve. by making the opening in the crash valve threaded i can screw in a length of PVC pipe that goes to a bucket. anything i put in the bucket goes through the system with just the normal pressure..no hose pressure.

as someone who has opened his hatch and seen about 14 inches of salt water in the bilge (15 miles from home)i can assure you that having crash valves can be a real comfort.

AndreF · Post by **AndreF** » Nov 15th, '10, 00:18

As UV told me one time after beating some mighty tall waves when we got back to Port Eads and saw alot of water in the bildge- "we were sinking and didn't even know it, but it made the boat handle better" Oh yeah, then - "I need a drink" Me too

Rocky · Post by **Rocky** » Nov 15th, '10, 17:29

And don't forget to replace the backing pads with material of choice, Epoxied Ply, Epoxied Coosa, PVC foam board and some wood species that grows underwater? Just throwin it out there.

bob lico · Post by **bob lico** » Nov 15th, '10, 20:34

rocky that wood is my first choice from experiance both bad and good i call it epei some say epi but buju has the professonal name.i have seen plywood self destruck as well as mohagony but just plain untreated epi 5/4" thick WOW!!!

randall · Post by **randall** » Nov 15th, '10, 20:42

epi's not really wood....its wood from a different planet. dosen't even float.

Rocky · Post by **Rocky** » Nov 15th, '10, 23:32

Yea that's the stuff, only concern I thought was it can split under pressure if end grain dries? But I guess you have good results with it Bob, must be O.K. with the clamping action the nut puts on it. I'd actually like to get some just to see it to get an idea what the hipe is with it! Must be tough as you said. I've got to remove my old internal strainers for external now that rear bulkhead is out and now's the time to choose pad material

randall · Post by **randall** » Nov 16th, '10, 10:15

rocky.....GOOD POINT.....all kidding aside it is extremely prone to end grain splitting if left untreated and exposed. when we built decks with it we coated the ends of every board with a special wax for that purpose.

Skipper Dick · Post by **Skipper Dick** » Nov 16th, '10, 10:59

I found a simple way to make fiberglass backing plates using a heavy plastic, flat bottomed bowl with a slight outward bevel. I waxed the bowl with carnuba wax and then mixed enough resin and milled fiberglass until it was about the consistancy of mayonaise and spooned it in the bowl. The bowl measured 5 1/2 inches in diameter and I mixed the resin so it would be a little slower. Once it kicked, I popped it out of the bowl and had a perfectly round 5 1/2 inch plate 5/8th of an inch thick. I drilled the center hole and bolt holes for the flange and I believe the plate will outlast any wood backing plate. It seems to be bullet proof and I'll epoxy them in tomorrow after it cures for a bit more.

Dick

PeterPalmieri · Post by **PeterPalmieri** » Nov 16th, '10, 11:05

Dick,

Can you snap and post a few photos when your done?

If anyone has some pictures they can post of the entire system with the crash valve and the attachment for winterizing that would be awesome.

Skipper Dick · Post by **Skipper Dick** » Nov 16th, '10, 11:45

Pete,

I should be able to get most of it re-insalled tomorrow and the next day after waiting for the backing plate epoxy to cure. I'm waiting on the bronze bolts to arrive today, but every thing else is ready. It amaizes me that all the local marine shops that sell thru hulls and stopcock flanges do not carry the bronze bolts for the flanges and I had to go online.

I'll get some pics posted when it is complete. I even have a crash valve setup for each side.

Dick

bob lico · Post by **bob lico** » Nov 16th, '10, 19:24

once again peter come to my boat at oakdale yacth and you can actually look, touch and work the vaves .i can also show you the bertram installed crash valves installed on the bertram 510 . i also run a 45' cabo express with the same system. you can check that also--------------bob

PeterPalmieri · Post by **PeterPalmieri** » Nov 16th, '10, 20:08

Ok if you insist. Are you down there during the. Week or only on the weekends?

Tony Meola · Post by **Tony Meola** » Nov 16th, '10, 22:45

The other option is to order fiberglass sheet. This is what we used. Pick your thickness. We used 1/2 inch and by the time we glassed it in and used the cloth it was an inch thick.

http://www.mcmaster.com/#fiberglass-sheets/=9r2ci8

bob lico · Post by **bob lico** » Nov 16th, '10, 23:00

hit and miss at this time of year . not test riding center consoles anymore.-------- way to dangerous in big waves! call cell 516-639-9803

gplume · Post by **gplume** » Nov 17th, '10, 21:45

I can't beleive it, but I have no pix of my set up. I think you would like it. One lever to open inside valve, one to close seacock...into crash valve mode fast and furious if need be. I have threaded access plug for cleaning, and winterizing. The only pix I have are of the backing plates I did on may parents boat....(did both boats at the same time. so similar materials) Got the backing material from Bob Higgins B 31 restoration...its scrap bulkhead material. About 3/4 - 1 " marine plywood with glass epoxied on inboth sides. If you know Bob and have seen his work, then you know the materials are top shelf (thanks Bob!). I epoxied mine in with west system, and then epoxied the whole set up once installed. I am out of the water now, but will probably be down to the boat within the next week and will snap some photos. I really like the way my set up came out.

gplume · Post by **gplume** » Nov 23rd, '10, 21:31

Below is my set up. (Bilge is a littly swilly by this time of year) I took inputs from everyone before doing the job. Got the exteranl strainers as recomended by Captain Patrick. The access port wroked really well for winterization. Very easy to go into crash pump mode. BTW, dod not want to have to replace the hoses(did that the year befiore), so extended outlet to where it was with my old seacock/strainer set up.

Rocky · Post by **Rocky** » Nov 28th, '10, 22:21

Gif looks like you did similar to Bob Lico's crash setup, looks great. Possible question for the Capt., on my 31 it sits on a trailer. I would really like to put my intakes were Gif/Bobs are, in looking at the cradle diagram it looks like for storage of the 31 only needs KEEL support at transom, and first 6' of bow area, otherwise bunk support on chines as stated. I have support were this shows so, no center keel support needed were intakes would go behind batteries, doable? It would seem to simplify getting to valves esp. in an emergency and uncluttering were trans/shafts are located.

http://www.bertram31.com/specs/B31CradleDiagram.pdf

Tony Meola · Post by **Tony Meola** » Nov 28th, '10, 22:57

Rocky

I think they all came from the factory with the intakes right under the step. I am assuming someone move yours to the shaft alley. My 31 sits on the factory cradle for the winter. The bunk is actually forward of the intake. The bunk sits right behind the bulkead going into the cabin is. I am assuming it is right there to support the weight of the engines.

You should actually have no problem with the intakes if you set them back under the step.

Rocky · Post by **Rocky** » Nov 29th, '10, 13:09

Tony I looked at my area were rear bulkhead is in bilge and see all uniform green glass, doesn't look like on mine they were ever there. I guess my question is a hull support question in that trailering boat and storing it want to make sure chine support only is fine at engines area without centerline/keel bunks. My trailer manufacturer said I'm overthinking support on centerline(keel), as the 31 has excellent strength under the inboard and outboard stringers were bunks are now. Just want to be sure BEFORE drilling new large holes in hull, I always love doin that. And then of course following the Capt's guidlines on glassing in holes.

CaptPatrick · Post by **CaptPatrick** » Nov 29th, '10, 13:31

Just leave the raw water through hull fittings where they are and plumb the crash valves over to them... That's what I did on Hancock's B31.

Bertram used both locations over the years. Don't know if there's a rhyme or reason for it, or if there was one particular year that they switched locations.

Rocky · Post by **Rocky** » Nov 29th, '10, 16:48

Got it Capt Pat thanks., I went to those pics you had on handcock's boat for crash valves: another fairly simple effective design with just a plumbed "T" fitting between engine pump and intake. Now's the time while rear bulkhead is out lots of space to work. All made up, it's ready to be tabbed in. I'll use the 2" external strainers with 1 1/2" valves.

Capt.Frank · Post by **Capt.Frank** » Nov 30th, '10, 09:45

Gif,
What are the little round things in the hull for? They have a bounding wire to them it looks like.

Tony Meola · Post by **Tony Meola** » Nov 30th, '10, 22:14

Capt Pat

Thanks, go figure, every 31 I have ever been on always had them under the step. That was original before the days of rebuilds.

Skipper Dick · Post by **Skipper Dick** » Dec 1st, '10, 09:37

Capt. Frank,

I wondered about those round things too, but then it dawned on me that they were probably little round backing plates for the external strainer and the screws that came through were used for bonding the strainers.

That's my theory.

Dick

gplume · Post by **gplume** » Dec 5th, '10, 10:37

Round items are the hole plugs from drilling out the backing plates. I had a bunch of them around, and they looked like the right item to back the strainer bolts. I used them to back the bolts through that hold the external strainers in. Followed instructions from this site on mounting groco external strainers. Leading side bolted through.

Regarding the external strainers, I had ok results with the external strainers. A little blockage due to growth but nothing serious. I beleive this approach is good as long as you properly coat the strainer with antifouling somthing....I used some left over propspeed. I live in a very high growth part of narraganset bay, so strainer blockage was a concern for me.

gplume · Post by **gplume** » Dec 5th, '10, 10:41

By the way.......Anyone have any idea why Bertram put the drain plug in the center in late model hulls? (I have seen rearplugs on earlier models)

You see I have some water in my bilge, mixed with a little non tox antifreeze. Even after putting big arrows show wher ethe plug is, my yard neved seems to getthe pitch right so that the water flows to the drain.

Most years i go down and level the boat myself with a bottle jack.....but this year I did not get to it yet. Life would be easlier with a trear drain.

In Memory Walter K · Post by **In Memory Walter K** » Dec 5th, '10, 11:15

I finally surrendered. Ive wintered in several marinas over the years and I never could get them to understand. If I did, it was for one winter only...and because I was there. A Shop Vac visit every so often until it is completely covered was my solution.

Tony Meola · Post by **Tony Meola** » Dec 5th, '10, 21:12

I should cosider my self lucky. I sit in a cradle for the winter. The yard got it right every year but one. However, they haven't moved my cradle for 15 years so it is now right every time. Plus I have a reserved spot and on one is usually behind me since I am right on the edge of the path the travel lift uses to move boats around.

Raw Water Intake

Raw Water Intake

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