Reply
 
Thread Tools Search this Thread Display Modes
 
Old 02-27-2018, 08:29 PM   #1
Guru
 
Simi 60's Avatar
 
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 3,432
Screen over raw water intake.

A few days back I had a preemptive water temp alarm go off at 45c . water flow was down so cleaned the weed screen and continued.

While that improved the water flow marginally it turns out the main offender was a blockage outside so this morning fired up the hookah and sorted it out.

Big lump of something that as soon as I touched it with a scraper it dropped off, so I doubt it was growing.
To my surprise, there is no screen/scoop over the raw water intake and no evidence of there ever being one.

Normal or not?
__________________
Advertisement

Simi 60 is offline   Reply With Quote
Old 02-27-2018, 08:38 PM   #2
Guru
 
Simi 60's Avatar
 
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 3,432
Just found this
Some yes some no

http://www.trawlerforum.com/forums/s...take-7421.html
__________________

Simi 60 is offline   Reply With Quote
Old 02-27-2018, 08:42 PM   #3
Guru
 
psneeld's Avatar
 
City: Ft Pierce
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 23,677
I have had them and hate them.

No way to reem out from inside the boat.

My secret is to oversize the thru hull by at least 2X the required hose intake and the flow is so little, not much gets sucked up. If it does, clean the strainer, pull the hose and ramrod the through hull all from the inside.

I have 15,0000 miles on my trawler with only one instance of a blockage...3 small fish swam up and clogged the inside strainer....

Plus thousands of hours on an assistance towboat where the regular bottom strainer got clogged and I swirched to the non screened through hull to finish the tow and get home.

Marine Sail or whatever his new site is callex has some good insight on external strainers.
psneeld is online now   Reply With Quote
Old 02-27-2018, 08:43 PM   #4
Guru
 
LaBomba's Avatar
 
City: Beaverton, Ontario
Vessel Name: Looking Glass
Vessel Model: Carver 370 Voyager
Join Date: Nov 2012
Posts: 1,240
I had the exact same thing happen to me in 2016. Last spring I added a scoop to the bottom. The weeds on mine were sucked right up in the hole tightly. Had to put the washdown hose down the inlet hose to unblock. I feel better now.
__________________
Allan
LaBomba is offline   Reply With Quote
Old 02-27-2018, 09:08 PM   #5
Guru
 
Simi 60's Avatar
 
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 3,432
No access on the inside for us.
Intake has a 90degree elbow and short run of stainless pipe to the strainer which is now in a convenient and easily accessible spot.

When we got the boat the strainer needed a midget contortionist to access so it was changed on the initial inspection/survey lift.
Simi 60 is offline   Reply With Quote
Old 02-27-2018, 09:14 PM   #6
Guru
 
psneeld's Avatar
 
City: Ft Pierce
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 23,677
have access over the through hull at all?
psneeld is online now   Reply With Quote
Old 02-27-2018, 10:13 PM   #7
Guru
 
Simi 60's Avatar
 
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 3,432
Quote:
Originally Posted by psneeld View Post
have access over the through hull at all?
Nope, 90 degree elbow and a short run of stainless pipe to strainer.
Gate valve on elbow and strainer

Like I said, need to be a contortionist midget to access through hull and first gate valve, hence the short run of stainless to the new position.
Simi 60 is offline   Reply With Quote
Old 02-27-2018, 10:17 PM   #8
Guru
 
HopCar's Avatar
 
City: Miami Florida
Vessel Name: Possum
Vessel Model: Ellis 28
Join Date: Aug 2011
Posts: 4,865
Some boat builders are installing Groco APHS external strainers and eliminating the traditional internal sea strainer. I installed one on Possum but left the sea strainer inside. It got about a year of use and I never had to clean the sea strainer. https://www.groco.net/products/raw-w...er/aphs-series
Attached Thumbnails
F19B4002-1CE0-48C4-BA72-B52447D27696.jpg  
__________________
Parks Masterson
HopCar is online now   Reply With Quote
Old 02-28-2018, 12:01 AM   #9
Senior Member
 
City: Hervey Bay
Join Date: Nov 2016
Posts: 125
If you install an internal intake strainer above waterline with a straight pipe run down to the seacock, you can just take the lid off and rod it out when necessary.
D.Duck44 is offline   Reply With Quote
Old 02-28-2018, 12:29 AM   #10
TF Site Team
 
Insequent's Avatar
 
City: Brisbane
Vessel Name: Insequent
Vessel Model: Ocean Alexander 50 Mk I
Join Date: Mar 2012
Posts: 3,294
You could replace the 90° elbow with a T. Then part of the T will run straight down.
Attached Thumbnails
Groco Engi strainer 1 sml.jpg  
__________________
Brian
Insequent is online now   Reply With Quote
Old 02-28-2018, 01:50 AM   #11
Guru
 
Simi 60's Avatar
 
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 3,432
Quote:
Originally Posted by Insequent View Post
You could replace the 90° elbow with a T. Then part of the T will run straight down.
Certainly something to think on if it can be done without getting someone with a TIG in to cut and redo the plumbing I had done previously.

It would need a sealing cap on top and several feet of pipe to screw in to get the top above the waterline.

To do that I would have to remove a section of floor, wind gate valve about 50 turns to close, remove cap, screw in pipe and stuff a stick down it.

Reverse procedure and its time for an adult beverage
Simi 60 is offline   Reply With Quote
Old 02-28-2018, 06:52 AM   #12
Guru
 
psneeld's Avatar
 
City: Ft Pierce
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 23,677
The T iconfiguration s what. I was getting at...it doesnt "have" to be all the way above the waterline.... and a ball valve on top instead of a cap makes shutting off simple.

Used one for years when the other thru hull would get packed with sand, mud, grass, weed etc....would just swap the intake hose to its barb and open the through hull. By the time I got back to the dock, often the regular strainer would be washed out enough to use again. Plugged strainers never prevented me from accomplishing a tow despite working in an area that stopped others quite often.

Heck, even cleaning the front of the oil cooler was easier than trying to free up the external strainer.

The grates Hopcar posted are less prone to weed, but I and with oversized intakes, much less so. As far as opening...not sure how much of an underway feature that really is.
psneeld is online now   Reply With Quote
Old 02-28-2018, 07:01 AM   #13
Guru
 
Tom.B's Avatar
 
City: Cary, NC
Vessel Name: Skinny Dippin'
Vessel Model: Navigator 4200 Classic
Join Date: Jul 2009
Posts: 5,799
Quote:
Originally Posted by Simi 60 View Post
No access on the inside for us.

Intake has a 90degree elbow and short run of stainless pipe to the strainer which is now in a convenient and easily accessible spot.



When we got the boat the strainer needed a midget contortionist to access so it was changed on the initial inspection/survey lift.


Umm... yea... the sea strainer seems to be important enough that you should really consider moving them the next time you are on the hard. Is that possible?
__________________
2000 Navigator 4200 Classic
(NOT a trawler)
Tom.B is offline   Reply With Quote
Old 02-28-2018, 10:55 AM   #14
Senior Member
 
City: Washington
Join Date: Nov 2017
Posts: 468
Quote:
Originally Posted by HopCar View Post
Some boat builders are installing Groco APHS external strainers and eliminating the traditional internal sea strainer. I installed one on Possum but left the sea strainer inside. It got about a year of use and I never had to clean the sea strainer. https://www.groco.net/products/raw-w...er/aphs-series
My boat has that and it works well. It has one on the engine intake and one on the AC intake.
aboatman is offline   Reply With Quote
Old 02-28-2018, 11:49 AM   #15
Guru
 
GoneFarrell's Avatar
 
City: La Conner, WA
Vessel Name: Imagine
Vessel Model: Farrell 34
Join Date: Oct 2015
Posts: 547
Are any of you with the T fitting setup using that to flush the heat exchanger with fresh water at end of boating season? Methinks this could extend operating time between cleanouts for my heat exchanger.
GoneFarrell is offline   Reply With Quote
Old 02-28-2018, 12:19 PM   #16
Guru
 
Vashon_Trawler's Avatar
 
City: St. Petersburg, Florida
Vessel Name: M/V Sherpa
Vessel Model: 24' Vashon Diesel Cruiser
Join Date: Jun 2013
Posts: 591
Quote:
Originally Posted by GoneFarrell View Post
Are any of you with the T fitting setup using that to flush the heat exchanger with fresh water at end of boating season? Methinks this could extend operating time between cleanouts for my heat exchanger.
Yes, I have engine flush with bronze valve, hose, and stainless strainer. I simply spliced the line and clamped. It will also function as an emergency bilge. I fresh water flush after every trip. I purchased mine through yachtsofstuff.com
__________________
“Go small, go simple, go now”
― Larry Pardey, Cruising in Seraffyn
Vashon_Trawler is offline   Reply With Quote
Old 02-28-2018, 03:11 PM   #17
Guru
 
Simi 60's Avatar
 
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 3,432
Quote:
Originally Posted by Tom.B View Post
Umm... yea... the sea strainer seems to be important enough that you should really consider moving them the next time you are on the hard. Is that possible?
What, like cut another hole in the timber planking and do some type of fill on the old?
Then get someone in at great expense to cut and reweld the s/s pipework again?

No, can't see that happening, current through hull has been OK in that position since 1977.

This might be a suitable and faaaaar more affordable option



https://m.ebay.com.au/itm/Drill-Powe...QAAOSwA~VaL3CK
Simi 60 is offline   Reply With Quote
Old 02-28-2018, 03:30 PM   #18
Guru
 
diver dave's Avatar
 
City: Palm Coast, FL
Join Date: Jan 2017
Posts: 2,002
Quote:
Originally Posted by HopCar View Post
Some boat builders are installing Groco APHS external strainers and eliminating the traditional internal sea strainer. I installed one on Possum but left the sea strainer inside. It got about a year of use and I never had to clean the sea strainer. https://www.groco.net/products/raw-w...er/aphs-series
That would have to have a throw away screen to work in a high fouling area, like S FL. I had that external weed strainer that was a large, tilted, bronze plate with 1/8" perforations, and it was close to a nightmare to keep growth off it. Yes, I used Trinidad and at the 12 month mark had even oysters on it.
diver dave is offline   Reply With Quote
Old 02-28-2018, 03:53 PM   #19
Guru
 
Simi 60's Avatar
 
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 3,432
Quote:
Originally Posted by diver dave View Post
That would have to have a throw away screen to work in a high fouling area, like S FL. I had that external weed strainer that was a large, tilted, bronze plate with 1/8" perforations, and it was close to a nightmare to keep growth off it. Yes, I used Trinidad and at the 12 month mark had even oysters on it.
My thoughts exactly.
Simi 60 is offline   Reply With Quote
Old 02-28-2018, 04:06 PM   #20
Guru
 
Lepke's Avatar
 
City: Between Oregon and Alaska
Vessel Name: Charlie Harper
Vessel Model: Wheeler Shipyard 83'
Join Date: Jun 2016
Posts: 2,334
You can see the bonding wire between the strainer and thru hull. Without a metal connection, in similar, but bad installation, the zincs don't protect the strainer and the bronze will shed zinc becoming porous. The basket, too depending on the material.
My current boat had a rubber hose from the seacock to the strainer and another hose from the strainer to the salt water pump and no bonding. When inspecting the strainers (solid cast iron) the strainer baskets were gone. So the po had been running the engines w/o a strainer for years. I also had copper pipe sink drains I had to replace because there was no bonding with a hose connection. You could see the parts below the water line where the pipe was paper thin.
Attached Thumbnails
attachment.jpg  
__________________

Lepke is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 08:31 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×