Rectangular Scoop Sea Strainers

[TomT13]

Hello, has anyone used the rectangular scoop sea strainers on their boat for the AC and Generator pickups? The mechanic completing my repower wants to remove the Perko strainers from inside the boat and replace with exterior scoop strainers for the main engines. He recommends not doing so for the generator, head and he wasn't sure about the AC. I have a sportfish that will cruise at 25 knots. He expressed concern that water may be forced up into the genset with the scoop strainers. Just wondering if anyone on the HOF has experience otherwise. Thank you.

 

[Yachtsmyth]

Hello,
I have heard the same concerns. They are good for mains and AC, but not gen as they will force water in.

 

[Pascal]

I put them on my 53 when I repowered for the mains and air cons. They work great.

Indeed can’t be used for gensets as it would force water in and drown the engine. Unless you drill holes in the back and your diver cleans them. Not worth it.

I ve used them on boats i ve run, in fact I had them installed last month for air con and water makers on the 116 I run.

 

[Captain Ralph]

May I offer some thoughts;

You are still going to have a seacock and hose on the inside of the hull. Will removing the inside strainers save that much room?

Are you having any performance issue with what you have?
Your existing strainers are due to be serviced, repaired or replaced?

Do you have a scheduled dive service to inspect and clean the the external strainers?
I do not have them on my boat but am concerned with out regular boat use (dock sitting) they may fowl in some waters.

This is not a cheap mod.

External strainer conversations have come up before. It does seem that those that have them are happy.
Without spending any money, I'm still happy with my 44 year old Perko & Groco designs.

 

[Pascal]

On some cases the space saving matters, it depends on the boat. On classic Hatteras with keel tanks the strainers have to be in the ER(s) and take quite a bit of space.

They are especially practical for air con which pretty much runs non stop. In some spots you have to clean the strainers every couple of weeks

 

[52CMY]

They good if you can keep them clean by diving them or running your boat enough. I have them on my engine intakes and are great so far. My HVAC mech recommends them for HVAC too--he believes that the clear glass strainers (even in the dim light of an ER) create a greenhouse for the mucky growth to grow that we get in Galveston Bay and Clear Lake. Jury is out on that.

Note that you'll want to bottom paint them carefully as the 100s of holes are small enough to get clogged with paint if it's slathered on, inhibiting water flow over time.

 

[TomT13]

Thank you all for your input. I will be using them for my mains and AC. Capt. Ralph, the actual strainers inside the glass housings on all my Perko's are having issues. Handles are coming lose, bronze bottom's are falling out. I know they can be replaced but it will make more room to gain better access to the seacocks and I won't have sea water spilling in the freshly painted bilge every time I clean them. I use my boat regularly as I am not a dock sitter and we have multiple divers in the marina so I’m not too concerned with buildup. Have a great holiday everyone!

 

[Captain Ralph]

Reads like some new exterior strainers will be under a tree this year.
Merry & safe Christmas and holidays.

 

[Bernd1972]

Obviously for generators and such it is for good reason recommended to install them backwards (with the open side to the back of the boat)

 

[rsmith]

In Florida we work weed lines that form in the Gulf Stream. These are far more susceptible to clogging externally than the traditional perkos due to their flat shape.

 

[Scarlett]

If you really want to be crazy you can do what I did and after the bottom is painted use a tooth pick dipped in bottom paint and push it through every hole which both opens up the hole and coats the inside of each hole. Takes a few hours but hopefully worth it. In So Cal we only haul our boats every 3 years or so.

 

[Pascal]

The screens are removable, easy to pull before painting or to scrub the inside

Unlike slotted thruhulls the small holes don’t catch sea weed. When anchored in the exumas we often have issues with sea weed getting stuck in the slots. Doesn’t always get out when running and going under is the only optikn

 

[scottinsydney]

What is the brand of these scoops and size required for the engine intakes please?

 

[jim rosenthal]

I have those strainers on my engine seawater intakes. They have done well for me, I pull the screen out in the spring and spray paint them with Barnacle Barrier. Last year I had to replace the bronze screens, but they lasted quite a long time.

I tried stainless screens early on. They don't work; they fouled almost immediately.

Agree on the strainers for gensets- thos are supposed to have mushroom strainers that don't force water up into the genset and drown its engine.

 

[Play'N Hooky Too]

What is the brand of these scoops and size required for the engine intakes please?

If you hover over the picture in the OP a brand and Part No. will pop-up.
(Buck Algoquin - Hull Intake Strainer- Part No. OORSS655PF).

Not sure if this is the one that will fit your boat though. I would check the dimensions.

 

[scottinsydney]

I've taken a look at the manufacturers catalogue. Page 95 Positive Strainers

https://www.hydrasearch.com/media/w...reational_Catalog_621_Pages_Email_Version.pdf

Looking at this design, the base would be permanently affixed to the hull and should never need to be removed??? Am I correct? With the screen removed it can be scraped and painted on the inside and out.

Am I also correct in staying the huge engine Perko strainers could be removed and replaced with a simple seacock and hose to the pump? (I removed 5 Perko strainers last time the boat was slipped replacing / repositioning fittings with hull mounted shower roses. Works the same and less fuss.

 

[Avenger]

Yes, dump the internal strainers entirely. You really don't have to worry about cleaning and painting the insides. Properly made strainers will have the backsides drilled so the holes have a knife edge. I've never had an issue, and trust me, I see plenty of marine growth. Can't speak to the ones with removable stainless plates. That's a different program.

Sizing: The manufacturers will recommend sizes. Obviously you'll want to meet minimums, but otherwise get the biggest ones you can manage. It's hard to have too much strainer.