Opinions? - Marelon MF810 water strainer

[Nick F]

I am reworking my raw water intake system and am thinking of scrapping the current heavy (literally weigh some 45lb each), bulky bronze duplex strainers.

Can anyone speak from experience in regard to this Marelon strainer?

[Comodave]

Why would you want to get rid of the bronze ones? Are they broken? What volume does the Marelon strainer hold compared to the bronze ones?

[mvweebles]

While no experience with the Marelon strainer, I've given up on Marelon valves due to breakage issues with valve handles. I am okay using Marelon mushroom thru-hulls above waterline, and the vented loops are fine. But I shy away from anything with two or more parts.

What problem are you trying to solve? Weight is down low so not an issue. Guessing your old ones are original to the boat and have lasted at least 48-years which is impressive when you think about it. I know bronze fittings are expensive, but they do last. And if you're near a marine salvage store, you can often find used ones.

Good luck with whatever you decide.

Peter

[helm]

We had those strainers on our Lindell 36. The reason for had is the design, they are bottom in and side out, but the inlet side is obstructed by the molded in supports for the threads that will retain the center bolt on that knurled knob.
So if you are in an area with long stringy weeds they will not make it into your strainer and simply jam up your inlet hose above the thru hull - not a lot of fun.
On the delta we deal with Brazilian water weed which is a menace. I took out the marelon strainers and replaced them with Arctic Steel bottom in side out strainers which have worked great for our engines. We put an external strainer on our generator thru hull and kept the marelon strainer in that location. If you really decide to go with the Forespar strainers PM me I have a couple you could buy.
Best advice, keep what you have if it works.
Best
Eric

[O C Diver]

Had one of those on my generator when I bought the boat. The lid cracked.

Ted

[Comodave]

Originally Posted by O C Diver

Had one of those on my generator when I bought the boat. The lid cracked.

Ted

That would be my concern too.

[helm]

We have all Marelon thru hulls and seacocks with zero issues. Never a cracked lid on a strainer which seems like it would be the result of aggressive tightening. The picture however shows the strainers Achilles heal which is obstruction of the inlet by the tripod supports for the lid fastner which causes debris to hang up in the hose and never make it to the strainer basket

[Nick F]

In response to questions about why I dislike the present strainers in my boat:

They are bulky - occupy a lot of space.
They are extremely heavy - although, since my boat is heavy and slow, this is normally not a problem.
The plexiglass tubes are somewhat frosted.
They need new gaskets which I will have to have custom cut from sheet rubber.
I really don´t need the duplex changeover feature.
I have to re-locate the strainers anyhow to give myself more battery space.
They are old and grungy looking. A previous owner has covered them with a type of preserving vaseline that looks like ghostbuster slime.
To clean the strainer requires dumping the water and removing the plexiglass tube - you cannot just lift the basket out.
Yes, they are bronze and will last another 100 years (they look like they belong on the Nautilus with Capt. Nemo).

Ya - de - ya - de - ya . . .

[Comodave]

I would probably get rid of those odd looking strainers but would go back with some other bronze ones.

[Bmarler]

Originally Posted by Nick F

In response to questions about why I dislike the present strainers in my boat:

They are bulky - occupy a lot of space.
They are extremely heavy - although, since my boat is heavy and slow, this is normally not a problem.
The plexiglass tubes are somewhat frosted.
They need new gaskets which I will have to have custom cut from sheet rubber.
I really don´t need the duplex changeover feature.
I have to re-locate the strainers anyhow to give myself more battery space.
They are old and grungy looking. A previous owner has covered them with a type of preserving vaseline that looks like ghostbuster slime.
To clean the strainer requires dumping the water and removing the plexiglass tube - you cannot just lift the basket out.
Yes, they are bronze and will last another 100 years (they look like they belong on the Nautilus with Capt. Nemo).

Ya - de - ya - de - ya . . .

I had that exact strainer in my last boat. It’s a really excellent unit, and will indeed last forever. I lapped mine when I was refitting the boat and it worked like new. Price a new one and you’ll gain some respect for it.
Maybe you can work a trade with someone for a small one.

[Nick F]

@Bmarler - I searched, but could not find a manufacturer (Gross?) and could not find one on Google images.

[Bmarler]

Originally Posted by Nick F

@Bmarler - I searched, but could not find a manufacturer (Gross?) and could not find one on Google images.

I was thinking it was an older groco strainer. They still make duplex strainers but I couldn’t find a horizontal format, here’s a link to the modern iteration from fisheries website.
https://www.fisheriessupply.com/groc...onze-strainers

[Nick F]

Originally Posted by Bmarler

I was thinking it was an older groco strainer. They still make duplex strainers but I couldn’t find a horizontal format, here’s a link to the modern iteration from fisheries website.
https://www.fisheriessupply.com/groc...onze-strainers

Thanks Bmarler - must indeed be early Groco. I just looked at the Groco site and their full name is "Gross Mechanical Laboratories". This same Gross name is on the casting of my unit. The current design has the removeable basket - which answers one of my complaints regarding my early units.

[C lectric]

Why not contact Groco. Send a photo of your current unit. Maybe they can suggest an update for your unit and a better setup for the glass removal.


There are still three mfgrs. of high quality bronze strainers like this, Groco, Buck Algonquin, Perko which is what mine is.
Take a look at their offerings before chucking what you have.
As for the frosted sight glasses they can be polished or simply replaced. I replaced my Perko sight glass with 4" diam x 1/4" wall acrylic tubes

San Juan Engineering , now Orca Marine used to make a pancake bronze strainer with a clear polycarbonate lid held with a single stud. Try them for a pancake type strainer.
Custom Design & Assembly of Marine Heat Exchanger & Cooling Systems - Orca

Yes I like the bronze items.

[mickand]

I agree with Helm's comment - the entry is easily blocked and is a pain to clear. I fitted a Marelon for my gen due to lack of space for a Groco - I tolerate it but can't recommend it as it clogs too easily in 'grassy' areas. I normally have to remove the strainer to clear as it 'packs' grass tightly in the narrow neck.

[Lostsailor13]

Recently installed a new 1 1/2 Perko bronze sea strainer and raw water intake pump,was pretty costly but so worth it,don’t cheap out and install that crappy plastic thing