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Douglas Dorsi
02-28-2008, 08:26 PM
I am looking for any suggestions on installing a through hull water pickup on my classic 22 for improved cooling. Mechanic is suggesting leaving Bravo drive water hose in place to maintain current drive cooling and adding a through hull pickup for increased flow. The two would come together with a y fitting and flow into my sea strainer then on to the sea pump. Any suggestions would be appreciated from this talented group. Link to Stainless Marine Pickup I am thinking about is attached.

[URL="http://http://www.stainlessmarine.com/myProducts.CFM?CFID=5285541&CFTOKEN=26529441&parentcategoryid=53%7CWater%20Pickups&productID=57&showDetail=1&categoryID=53|Water%20Pickups&vendoridtodisplay=0&filterFor=&collection="]

gcarter
02-28-2008, 08:49 PM
http://www.donzi.net/forums/showthread.php?t=49388
Take a look at post #24.
My own feelings is NOT to keep the connection through the gimbal housing. Just remove the hose from the upper gear case and let the water flow through it back into the surrounding water. Make yourself a block off plate for the inside of the gimbal housing to seal it from water intering there. Then only use the new Stainless Marine pickup. Please note the shut off valve located inside the transom. I believe this is very important to have. There are a few members here who wish they had one at one time or another. :yes:

BlownCrewCab
02-28-2008, 09:03 PM
Do you have a water pressure gauge? If you can keep 5-10 psi water pressure you dont need to change anything. I Know some plumbing configs make more water pressure than others, but you don't want more than 15 psi water pressure. and if you decide to go that way, As GCarter said That shut off valve is mandatory in my book.

Tony
02-28-2008, 09:11 PM
Other than drilling another hole below the waterline, are there any other disadvantages to this style of pick-up?

The water pick-up on my DPX is low on the bullet, and prone to sand ingestion.
Don't ask me how I know this...

:beer:

gcarter
02-28-2008, 09:53 PM
Other than drilling another hole below the waterline, are there any other disadvantages to this style of pick-up?
The water pick-up on my DPX is low on the bullet, and prone to sand ingestion.
Don't ask me how I know this...
:beer:
Absolutely no disadvantages.

BigGrizzly
02-29-2008, 09:12 AM
No don't do it!! If you need one use a transom pick up on a 22. I have done the Y thing with a transom pickup. Just make sure both have a shut off.

gcarter
02-29-2008, 11:29 AM
No don't do it!! If you need one use a transom pick up on a 22. I have done the Y thing with a transom pickup. Just make sure both have a shut off.
Randy, would you mind sharing w/us why you feel that way????? I've seen you make this comment before w/o explanation. I just don't get it.
After all your TRS has only a through transom pickup?????:doh:

Tony
02-29-2008, 12:13 PM
Could it be fear of a lack of water due to air-time?
How often is that part of the hull bottom actually out of the water, even in aggressive conditions?
With the recommended shut-off valve, exactly what are the specific disadvantages?

Hopefully Randy Grizzly will chime in with his thoughts, as I too am considering a transom water pick-up.

:beer:

gcarter
02-29-2008, 12:36 PM
Actually Tony, w/a set up like this, you also include a sea strainer, so lot's of water is available.

BigGrizzly
02-29-2008, 05:32 PM
I would be glade to elaborate. First to du the hull pickup you have to put a hole in the bottom. first you need to know where it is to be placed on the bottom. If the pickup is set incorrectly at high speed it pulls water out. Then your faced with the planing surface of the hull will be irregular even if it could be placed in the center. With the transom pick up it is easier and can be tailored after installation. Next is leaks the farthur under the water the more leaks because there is always pressure around the fitting especially underway. With the transom pickup the entry point is usually 6 to 10 inches above the the entry point of the water ans a lot less pressure on the through transom fitting. People are forever playing with the straight bottom now you want to put a void in the most important part of the bottom. Btw all my boats have transom pickups the 16 the Corsican and the Criterion. I can go on but I think you get the points

Douglas Dorsi
02-29-2008, 05:52 PM
Everyone, thank you so much for your views.

The mechanic has now suggested using a through transom water pick up as their is very limited room to do a through hull pick up at the location it needs to go. I have attached the link to the one at Hardin Marine that is our current selection below. It is adjustable in height, has a 1.25" unrestricted flow and will be connected to the Y .The drive hose from the transom will be connected to the Y. The Y will be fabricated by Hardin Marine out of 316 SS. This will be plumbed into my existing strainer which is the Hardin Marine 10" high dual basket with 1.25" inlet & outlet connections. The strainer is mounted on the same ledge the battery is on and is on the starboard side. I have a flush connection through the deck to the strainer & I have an overpressure relief valve on the strainer which is vented through a side dump next to the bildge dump.

I was going to install a 1.25" SS groco ball valve after the Y connection but before the strainer. My mechanic says with the height of the strainer on the ledge it is sitting significantly above waterline at a standstill. Even if you open the strainer no water will flow in. Of course if you have a leak before the strainer or before the place where you would mount the valve you could have a problem as you describe.

I have not heard of issues with too much flow as mentioned but I guess it could be a problem.

If I leave the drive connected through the Y rather than blocked off and catch some air hopefully I will still get water flow. That was the thinking behind leaving the drive connected.

Again thanks for all your comments and any others you may have. The registry members are all just great.

[URL="http://www.hardin-marine.com/detail~ID~597.aspx"]

gcarter
02-29-2008, 06:15 PM
Here is a picture of the Minx w/its pickup.
http://www.donzi.net/forums/attachment.php?attachmentid=24272&d=1159816499
It always gave more than enough water supply. It did leak internally while underway. I just never got around to installing a pressure relief valve. You know these projects are never finished. It wan never an issue...I would just drain a gallon or two of water out while loading the boat. A relief valve would have fixed it.
As far as the shut off valve goes, the several members who wished they had one, suffered w/ hose failures at the gimbal housing....no where else.

Tony
02-29-2008, 06:28 PM
D. Dorsi your setup looks like it will work well.
It sounds like you are getting some good advice and have a marina on the same page.

My situation will require no Y, but a block-off of the existing pick-up since it is too low and prone to sand ingestion.
Then, after the transom pick-up, it sounds like I will have a shut-off, then a strainer/flush assembly.

Is the pressure relief valve and dump necessary?
How much pressure is too much?
Can an adjustable transom pick-up be set up correctly so that pressure is regulated and appropriate?

Sorry for the slight post hi-jack...and thanks to those who have experience with this topic and also take the time to share it!


:beer:

Douglas Dorsi
02-29-2008, 08:23 PM
Concerning the pressure relief valve on the strainer I do not have any direct experience. What I understand (please anyone chime in here to correct me if I am wrong) is that at certain speeds ( I assume slower ones) the inlet side of the sea pump ( strainer, hoses ect.) are under suction from that created by the pump. At higher speeds water is being forced into the inlet enough that the pressure can become high. As such you may reach pressures that should be relieved.

I am not sure at what pressure you should relieve the inlet side of the system. Any advice from fellow members would help here as to what the valve should be set at. Since 15 pounds appears to be the high side of what you might normally run at (my engine is the 496 HO) I would assume that would be about the right set point. My relief valve is from Hardin Marine, made out of brass and cost around $100. The relief valve is adjustable from about a few pounds to around 30 pounds. The dump is nothing more than a fitting through the side of the hull that is plumbed to the relief valve so that if the valve does relieve the water is dumped over the side of the boat instead of the bilge. My bildge is always dry and this helps keep it nice and tidy. My intallation should be complete next week and I will post pictures and comments to follow up on this thread.

Thanks, George, Tony, Grizzly, & Crew Cab!

tom freeman
02-29-2008, 08:42 PM
is the fitting a 128-5001 from hardin marine

Tony
02-29-2008, 11:05 PM
Below's a pic of my pick-up.
Would the bottom of the body be mounted flush with the bottom of the transom?
The adjustment is pretty minor, only about 3/8".

gcarter
03-01-2008, 07:23 AM
Tony, I'd mount it like you said. Chances are you're going to have it fully retracted anyway. These things supply a LOT of water. If it wasn't for no wake zones, you wouldn't even need a sea water pump.
As far as pressure goes, they almost work to the rules of a pitot so the pressure goes up w/the square of the speed.

p729lws
03-01-2008, 08:18 AM
Below's a pic of my pick-up.
Would the bottom of the body be mounted flush with the bottom of the transom?
The adjustment is pretty minor, only about 3/8".


Tony,
The body of mine was mounted about 3/16" ABOVE the bottom of the tramsom and then the tip was adjusted to be flush w/ the bottom. I had a strainer and never had any problems w/ this set up. I always ment to adjust it all the way up to see how it would run but never got around to it.

Around here with all the shallow sandy areas I'd never run w/ a drive pick up.
Dan

Tony
03-01-2008, 09:17 AM
Thanks George and Dan...exactly the kind of precise advice this board is famous for!
I'm prolly gonna put the thru-transom pick-up into a strainer. I'll put a temporary pressure guage into the line somewhere and, if it's running reasonable at speed I'll pull it out and forego the pressure dump mod.

Thanks again, guys.

:beer

Douglas Dorsi
03-01-2008, 09:57 AM
The fitting is Hardin Marine Water Pick-Up
410-BK-1084 .

BigGrizzly
03-01-2008, 10:00 AM
I have gone over this before, but here it is. This mostly applies to blown, supercharged and higher compression engines. Most of you probably have noticed rust marks just below the cylinder heads on marine engines. People think this is from water in the bilge splashing up-wrong. It cones from the head gasket water jacket. Upon dismantling the engine if you look closely you will see the head gasket weeping. Some times you need to look real hard but it is there. Maximum water pressure should b no more than 35 psi!! On a closed system it is not an issue because the block is never pressurized from re entry or speed. I have witnessed what 40psi does th a supercharged engine at 5500 rpms- not good!!

Douglas Dorsi
03-01-2008, 10:10 AM
So pressure is not an issue with the 496 HO closed cooling system it sounds like. I gave the wrong part number in my reply above, the numer is 128 -5000 for the relief valve itself and I only had to add a nipple for it to connect to the overboard dump hose. Part 128-5001 appears to be an in line fitting to put the valve on if you need it. My valve relieves at home garden hose pressure and the strainer is rated at 100 psi but I guess I should set the relief valve at something reasonable and not really sure what that should be. Any ideas would help!:shocking:

BigGrizzly
03-01-2008, 10:21 AM
Correct it should not be an issue on the 496, unless a raw water hose blows off due to loose fittings or weak hose.

Douglas Dorsi
03-01-2008, 10:35 AM
Thanks Randy!

This is good to know!

BigGrizzly
03-01-2008, 12:10 PM
Most heat exchangers are tested at 150 psi minimum however the gaskets are usually screwed on at 5 ft lbs of torque these seem to hold 75psi of water pressure on the raw water side with no problem. I have never seen one blow yet. I run my closed system-nit the raw water part with a 16 psi cap. mine came with a 5 psi cap- too low in my opinion. There are good arguments on both sides, so I picked that one, because of boiling points and cars run thqat with no issues.

gcarter
03-01-2008, 12:49 PM
Randy's bringing up some good points.
I usually forget about raw water cooled engines because my boat always has or will have closed cooling. and Randy's right about the test pressure on the HE.
when I first assembled my Minx, the raw water system held the estimated 50 PSI with no difficulties, but as time went on, one or maybe more of the connections started leaking while under way. The only way to find the leak generally is to climb in there and look for it while someone else drives. I never got around to it.

gcarter
03-01-2008, 12:51 PM
While pressure may not be an issue as far as the head gaskets are concerned with closed loop systems, how much pressure are the heat exchangers rated for?
A lot higher than the hoses.LOL:wink:

BUIZILLA
03-01-2008, 03:04 PM
when I first got the Critter, the first couple times I used it with the ratty 330, I saw dampening where the intake gasket meets the head, so I tried to tighten the bolts and they were very snug. Leaked the next time out. I solved that pressure buildup by drilling a .093 hole in the thermostat base to bypass some internal pressure backup, took a couple minutes longer to warm up after that, but the seaping completely stopped that day. This was with a RWC engine though..

tom freeman
03-01-2008, 07:33 PM
[quote=BigGrizzly;440500]I have gone over this before, but here it is. This mostly applies to blown, supercharged and higher compression engines. Most of you probably have noticed rust marks just below the cylinder heads on marine engines. People think this is from water in the bilge splashing up-wrong. It cones from the head gasket water jacket. Upon dismantling the engine if you look closely you will see the head gasket weeping. Some times you need to look real hard but it is there. Maximum water pressure should b no more than 35 psi!! On a closed system it is not an issue because the block is never pressurized from re entry or speed. I have witnessed what 40psi does th a supercharged engine at 5500 rpms- not good!![/quot


grizz,

as you know I have the stainless marine transom pick up and she runs at 147 degrees constant. Now I am worried about the pressure. I need to know wher to get the pressure release valve, i saw what i think is the part as mentioned earlier in this post... bottom line is what do I use for this pressure release, i have 1.25" hoses.

tom freeman
03-01-2008, 07:36 PM
[quote=tom freeman;440551][quote=BigGrizzly;440500]I have gone over this before, but here it is. This mostly applies to blown, supercharged and higher compression engines. Most of you probably have noticed rust marks just below the cylinder heads on marine engines. People think this is from water in the bilge splashing up-wrong. It cones from the head gasket water jacket. Upon dismantling the engine if you look closely you will see the head gasket weeping. Some times you need to look real hard but it is there. Maximum water pressure should b no more than 35 psi!! On a closed system it is not an issue because the block is never pressurized from re entry or speed. I have witnessed what 40psi does th a supercharged engine at 5500 rpms- not good!![/quot


grizz,

as you know I have the stainless marine transom pick up and she runs at 147 degrees constant. Now I am worried about the pressure. I need to know wher to get the pressure release valve, i saw what i think is the part as mentioned earlier in this post... bottom line is what do I use for this pressure release, i have 1.25" hoses.[/quo


is the fitting a 128-5001 from hardin marine

scott snider
03-03-2008, 08:16 AM
Mercury sells a Relief Valve Kit, you might want to look at, part number 863208A 3 . Its not cheap, I think it is around $300 but it probably would be what you need.

BigGrizzly
03-03-2008, 10:22 AM
Tom, I would not worry in your particular case. your running a Y connection with the Volvo lower unit. It will bleed some pressure off, unless your transom pickup is too deep. it only needs to be about 1/8 to 1/4 inch below the bottom. The merc valve is good, but expensive, there are other alternatives.

tom freeman
03-03-2008, 08:41 PM
[quote=BigGrizzly;440694]Tom, I would not worry in your particular case. your running a Y connection with the Volvo lower unit. It will bleed some pressure off, unless your transom pickup is too deep. it only needs to be about 1/8 to 1/4 inch below the bottom. The merc valve is good, but expensive, there are other alternatives.[/quote

my transom mount is flush on the transom in the front and then the back hangs down like .25" to .33". so i can just leave it alone and not worry. i was not worried until i read all this.

BigGrizzly
03-04-2008, 09:47 AM
That should be OK at the speeds you travel