Stainless vs bronze vs Marelon, SS screws

[SkunkBoat]

Underwater Thru Hulls-
Bronze has been the material of choice for hundreds of years. Which bronze? how do you know its not really brass? Are there stainless screws as part of the attachment?
What is connected to it? A bronze seacock with a stainless ball valve? Do you bond it or not?

Stainless is used on many brand new boats. Which stainless? 316? What is connected to it? A bronze seacock with a stainless ball valve? Do you bond it or not?
There is a possibility of crevice corrosion in certain circumstances

Marelon. Won't corrode. . What is connected to it? A Marelon valve? Won't conduct stray current. Ding ding ding...best choice

NONE of them claim to last forever.

Scuppers/Above water thruhulls-
They are above the water.
Plain bronze will turn green. Chromed Bronze will pit and turn green.
Stainless looks pretty but it will stain!
Marelon. Ding ding ding....

Common underwater stainless-
Trim Tabs, Thruhull Transducers, screws and hardware for transom mount transducers and UWLEDs, Inboard shafts, rudder pintles, I/O bolts, shafts, props, lower 2 bolts on every outboard, bolts holding every Zinc anode....

I have seen crevice corrosion in stainless screws. Both times it was the screws that hold the bilge pump bracket.

 

[seasick]

One disadvantage of Marelon is that as the thru hulls age, they become a bit brittle and can fail catastrophically in the mode where the tubes of the fitting cracks off. They are not as strong in general for shear forces as bronze. For that reason, my preference for fittings that if sheared off will result in flooding is bronze. Just my personal opinion.

 

[SkunkBoat]

One disadvantage of Marelon is that as the thru hulls age, they become a bit brittle and can fail catastrophically in the mode where the tubs of the fitting cracks off. They are not as strong in general for shear forces as bronze. For that reason, my preference for fittings that if sheared off will result in flooding is bronze. Just my personal opinion.

That has not been proven in testing. People think Marelon is the same as Nylon or other plastics. Its not.
I don't have any Marelon. Not selling it. Just saying that, on paper, its the best choice for Underwater fittings

Look at the pictures fron the scupper thread. Old bronze cracked around the rim and sheared off.

 

[Doc Stressor]

I've had really good luck with Marelon through-hulls and seacock/ball valve fittings over the years on aluminum hulls. All the stuff on the 1998 Siverstreak I sold to my buddy when I left the west coast is still original. It's a reinforced nylon that does not get brittle, at least when out of the sun under a hull. People confuse it with other plastic products used for drains and scuppers, but it is a very different product.

 

[seasick]

OK, I did some research and Marelon was highly recommended for thru hull aps and seacocks. I may change my opinion since the failures I remember seeing may not have been Marelon but rather a nylon composite.
With regard to scuppers though, I have not been able to find a Marelon scupper valve with flap.
In the original post, the issue was transom scuppers and the flap is critical to slow/stop water backing up into the deck or motor well.

So if anyone finds a Forespar Marelon scupper valve through hull, let me know.

 

[Chessie246G]

OK, I did some research and Marelon was highly recommended for thru hull aps and seacocks. I may change my opinion since the failures I remember seeing may not have been Marelon but rather a nylon composite.
With regard to scuppers though, I have not been able to find a Marelon scupper valve with flap.
In the original post, the issue was transom scuppers and the flap is critical to slow/stop water backing up into the deck or motor well.

So if anyone finds a Forespar Marelon scupper valve through hull, let me know.

I don't see them listed on their website. But you can get a T-H marine flapper cover that would attach to the Forespar scupper. 4 small screws to set it. Just an option.

 

[DennisG01]

Marelon is definitely one of those "special" things that isn't known about too well - although it's been around for quite a long time. It's glass reinforced. Another one of these "special" things is "Marinium"... It was expensive and got hard for manufacturers to keep using so it went away for a while. Some time ago Perko bought the rights to it and started making it again, though. Check it out.

 

[SkunkBoat]

OK, I did some research and Marelon was highly recommended for thru hull aps and seacocks. I may change my opinion since the failures I remember seeing may not have been Marelon but rather a nylon composite.
With regard to scuppers though, I have not been able to find a Marelon scupper valve with flap.
In the original post, the issue was transom scuppers and the flap is critical to slow/stop water backing up into the deck or motor well.

So if anyone finds a Forespar Marelon scupper valve through hull, let me know.

yep but again the scuppers are not underwater. You can put a flapper over a Marelon thruhull. or use SS or use bronze...

The discussion had diverged to SS vs Bronze and corrosion. Above water thru hulls can be any material you prefer.
I used SS because it looks nice and was way cheaper than chrome over bronze. Also, they are not up high and not going to have rust runs down the hull.

On other boats I have used nylon with a stainless rim for the higher thruhulls (bilge pump exit). They look nice.
the OEM Perko plastic scuppers lasted 25 years on that boat. I replaced with SS.

This 22 year old boat has four UW thruhulls/seacocks. I should replace them. When I do I'll probably use Marelon.

 

[Mustang65fbk]

As you probably all know by this point what my opinion is, based off the other thread that is very similar to the topic at hand. I was looking around the other night on the Grady White website and came across these two pictures of a brand new GW 208 Adventure with stainless steel trim tabs, and wait for it... stainless steel scuppers as well. If it's fine by Grady to do it then it's fine by me to do it to my own boat. These pictures show the scuppers just barely off the water line, and depending on waves, weight or how many persons are sitting in the back of the boat, I'd bet they see a fair amount of time under water.

Grady-White | Adventure 208 Walkaround Cabin

Grady-White 20-foot walkaround cabin Adventure 208: Easy to use walkaround style and a SeaV²® ride. Secure platform for fishing.

www.gradywhite.com

 

[seasick]

Barely off the water line is not underwater
I have seen lots of tabs painted with antifouling paint (applied over the proper epoxy primer). Mine are painted. The fact that the tabs are not treated doesn't necessarily mean they don't need it.

Have you ever seen a seacock thru hull or scoop made out of stainless?

 

[Chessie246G]

My raw water pick ups are bronze. Thru hull drains are all stainless. scupper are plastic..... for a reason. they will be getting replaced in a year or 2 when the transom gets replaced. Easier to just throw them away instead fo trying to clean. Replacements will likely be stainless. Unless i go a different route. Seachest of sort maybe.

 

[Mustang65fbk]

Barely off the water line is not underwater
I have seen lots of tabs painted with antifouling paint (applied over the proper epoxy primer). Mine are painted. The fact that the tabs are not treated doesn't necessarily mean they don't need it.

Have you ever seen a seacock thru hull or scoop made out of stainless?

Yes I have... also, Grady White uses stainless steel thru hulls along with their scuppers on their new boats. Or at least the 208 Adventure they do...

Grady-White | Adventure 208 Walkaround Cabin

Grady-White 20-foot walkaround cabin Adventure 208: Easy to use walkaround style and a SeaV²® ride. Secure platform for fishing.

www.gradywhite.com

https://www.amazon.com/SuperWhole-Female-Stainless-Handle-WOG1000/dp/B00PILUQ46/ref=asc_df_B00PILUQ46/?tag=hyprod-20&linkCode=df0&hvadid=241996632632&hvpos=&hvnetw=g&hvrand=15319096597885104803&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9033264&hvtargid=pla-579220954040&psc=1

Amazon.com : Mgoodoo 1pc Stainless Steel 316 Marine Boat Intake Strainer Thru-Hull Inlet 1" Filter Scoop : Sports & Outdoors

Amazon.com : Mgoodoo 1pc Stainless Steel 316 Marine Boat Intake Strainer Thru-Hull Inlet 1" Filter Scoop : Sports & Outdoors

www.amazon.com

 

[Fishtales]

Not a fan of any composite or new fangle material on a boat - especially in this application.
I've always used SS above (a couple of feet or more) the waterline and bronze below.

 

[SkunkBoat]

Your boat is glass fiber and plastic resin.

 

[seasick]

Yes I have... also, Grady White uses stainless steel thru hulls along with their scuppers on their new boats. Or at least the 208 Adventure they do...

Grady-White | Adventure 208 Walkaround Cabin

Grady-White 20-foot walkaround cabin Adventure 208: Easy to use walkaround style and a SeaV²® ride. Secure platform for fishing.

www.gradywhite.com

https://www.amazon.com/SuperWhole-Female-Stainless-Handle-WOG1000/dp/B00PILUQ46/ref=asc_df_B00PILUQ46/?tag=hyprod-20&linkCode=df0&hvadid=241996632632&hvpos=&hvnetw=g&hvrand=15319096597885104803&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9033264&hvtargid=pla-579220954040&psc=1

Amazon.com : Mgoodoo 1pc Stainless Steel 316 Marine Boat Intake Strainer Thru-Hull Inlet 1" Filter Scoop : Sports & Outdoors

Amazon.com : Mgoodoo 1pc Stainless Steel 316 Marine Boat Intake Strainer Thru-Hull Inlet 1" Filter Scoop : Sports & Outdoors

www.amazon.com

View attachment 25641

You are confusing above the water thru hulls with submerged water scoops like the pickup for the livewell or raw water washdown.

 

[DennisG01]

As you probably all know by this point what my opinion is, based off the other thread that is very similar to the topic at hand. I was looking around the other night on the Grady White website and came across these two pictures of a brand new GW 208 Adventure with stainless steel trim tabs, and wait for it... stainless steel scuppers as well. If it's fine by Grady to do it then it's fine by me to do it to my own boat. These pictures show the scuppers just barely off the water line, and depending on waves, weight or how many persons are sitting in the back of the boat, I'd bet they see a fair amount of time under water.

Grady-White | Adventure 208 Walkaround Cabin

Grady-White 20-foot walkaround cabin Adventure 208: Easy to use walkaround style and a SeaV²® ride. Secure platform for fishing.

www.gradywhite.com

View attachment 25639View attachment 25640

Mustang, we discussed this a few times, but that other thread where we were talking about this was (mentioned numerous times) in regards to plumbing BELOW the water line. Below = under water. This is sometimes the problems with opinions and internet stuff - if the the details (reading) aren't paid attention to, then misinformation can be spread.

 

[DennisG01]

Yes I have... also, Grady White uses stainless steel thru hulls along with their scuppers on their new boats. Or at least the 208 Adventure they do...

Grady-White | Adventure 208 Walkaround Cabin

Grady-White 20-foot walkaround cabin Adventure 208: Easy to use walkaround style and a SeaV²® ride. Secure platform for fishing.

www.gradywhite.com

https://www.amazon.com/SuperWhole-Female-Stainless-Handle-WOG1000/dp/B00PILUQ46/ref=asc_df_B00PILUQ46/?tag=hyprod-20&linkCode=df0&hvadid=241996632632&hvpos=&hvnetw=g&hvrand=15319096597885104803&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9033264&hvtargid=pla-579220954040&psc=1

Amazon.com : Mgoodoo 1pc Stainless Steel 316 Marine Boat Intake Strainer Thru-Hull Inlet 1" Filter Scoop : Sports & Outdoors

Amazon.com : Mgoodoo 1pc Stainless Steel 316 Marine Boat Intake Strainer Thru-Hull Inlet 1" Filter Scoop : Sports & Outdoors

www.amazon.com

View attachment 25641

Everything you posted here is not about underwater stuff. In regards to what Seasick was asking about on a boat, he was referring to ON A BOAT. The SS "seaock" you posted... of course we've seen SS stuff like that... but that's a SHUT OFF for use on land in plumbing systems. The SS strainer and Grady link... those, AGAIN, are being used ABOVE the water line.

Mustang, quite honestly, you're holding onto your OPINION and trying to justify it by doing all kinds of internet searching. We've been telling you facts based on real life experience and knowledge. It would be beneficial to listen your elders Did you know that 7 X 13 actually equals 28? I saw it on the internet so it MUST be true. Go ahead - google it - I bet you'll even find a video of a nice man explaining it.

 

[Chessie246G]

Not to stir the pot, BUT Groco does make both stainless and aluminum raw water pickups, seacocks and strainers. I guess they do have an application, just not on my boat.

 

[seasick]

Did you know that 7 X 13 actually equals 28? I saw it on the internet so it MUST be true. Go ahead - google it - I bet you'll even find a video of a nice man explaining it.

Wow, I remember the skit on Laurel and Hardy. If I remember correctly they were convincing their landlord (what was his name) that they owed $28 for 7 weeks at $13 a week.
I saw the proof of the math so it had to be correct

 

[seasick]

Not to stir the pot, BUT Groco does make both stainless and aluminum raw water pickups, seacocks and strainers. I guess they do have an application, just not on my boat.

We are beating this topic to death but it's too cold and raw in NYC for my old bones to work on the boat. in NY
I just skimmed through the Groco catalog and did not find and stainless scoops or strainer fittings. They could be there but I can't find them. If you search for stainless steel you will see lots of actual bronze strainers with stainless steel screens.