Stainless vs bronze vs Marelon, SS screws

HAHAHA...thats why I made this thread...so this discussion had a place to fester...:p

btw, there ARE stainless underwater scoops/ strainers. Some boat makers (even high end boat makers) use them on trailer/lift boats because they look pretty along with four 350HP motors and thats what people want. I have seen them. Airmar makes SS thruhull transducers. It is a fact. :cool:
 
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SkunkBoat said:
HAHAHA...thats why I made this thread...so this discussion had a place to fester...:p

btw, there ARE stainless underwater scoops/ strainers. Some boat makers (even high end boat makers) use them on trailer/lift boats because they look pretty along with four 350HP motors and thats what people want. I have seen them. Airmar makes SS thruhull transducers. It is a fact. :cool:
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I did look up Airmar and you are correct!
 
Ah yes, I guess I shouldn't buy some of those Seaworthy Innovations stainless steel scuppers then because one person said not to and because if I do, I think my boat will almost assuredly sink immediately after installing them as well as spontaneously combust and the rotation of the Earth will start to spin in the opposite direction :D
 
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Mustang65fbk said:
Ah yes, I guess I shouldn't buy some of those Seaworthy Innovations stainless steel scuppers then because one person said not to and because if I do, I think my boat will almost assuredly sink immediately after installing them as well as spontaneously combust and the rotation of the Earth will start to spin in the opposite direction :D
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As long as you don't bring bananas on board I think you will be OK.
 
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Mustang65fbk said:
Ah yes, I guess I shouldn't buy some of those Seaworthy Innovations stainless steel scuppers then because one person said not to and because if I do, I think my boat will almost assuredly sink immediately after installing them as well as spontaneously combust and the rotation of the Earth will start to spin in the opposite direction :D
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Still vastly missing the point and grossly over exagerating.

You seem focused on trying to find justification through internet research. Because a company makes something, doesn't mean it's best practice. Go back and re-read (and this time actually READ it) what I've written in each post. Try and comprehend what was writen, don't just gloss over it.
 
DennisG01 said:
Still vastly missing the point and grossly over exagerating.

You seem focused on trying to find justification through internet research. Because a company makes something, doesn't mean it's best practice. Go back and re-read (and this time actually READ it) what I've written in each post. Try and comprehend what was writen, don't just gloss over it.
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Your earlier comment was... "We've been telling you facts based on real life experience and knowledge. It would be beneficial to listen your elders ;)"... which I wouldn't necessarily really call facts or knowledge. It's your opinion, just like you've expressed multiple times as well as I've expressed multiple times.

You mentioned in the previous thread that.... "Bronze is a much more durable metal. SS will corrode underwater." which you then followed up with your very next opinion of... "I honestly don't know how well the SS would fair (or not fair). It's probably not (well, definitely not) something I would personally take a chance on. SS is also not "officially" approved for below the waterline. It's pretty well known in the marine industry that it's a no-go for SS. I don't know the answer, but if the boat sank due to a failed fitting... would the insurance company deny coverage due to installation of an unapproved item?" So which is it? Will it corrode or do you not know? You've said both statements or opinions and then go on to say it's not something you'd personally take a chance on. So exactly what kind of experience do you have with stainless steel below the water line when you haven't used it before, nor will you? That would be like me saying that a Chevy is a bad car when I've never actually owned one or driven one before. Also, you've never really proven anything like about how "SS is also not 'officially' approved for below the waterline." but again that's also just a blanket statement or opinion and I've yet to see you provide any sort of evidence or facts proving that statement. Along with the opinion you also mentioned about it being "pretty well known in the marine industry that it's a no-go for SS." Which just because that's your opinion or what you've heard, or read on Google, doesn't mean that it's at all accurate. Just like you're trying to dismiss my claims for what I've read on Google. Everything you've opinionated so far has been exactly that, only your opinion, with no links, facts or any sort of evidence included. Lastly, they do use Stainless Steel in the majority of underwater pipelines such as natural gas and so forth, which cover thousands and thousands of miles underneath the ocean. But I'm sure that won't change your mind, even though you admittedly have no experience using stainless steel under the waterline and I'm sure you'll continue to think the way you do, even though listening to us young bucks could prove to be beneficial at times as well ;)
 
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Most of what you've said I (or others) have already answered many times before so I'm going to skip over most of it.

No, it's not opinion. But if you would do your OWN research you would find the same things I am trying to educate you on. Grabbing a picture off of Grady's website showing ABOVE the waterline fixtures has no bearing on what we're talking about except to show that you don't yet understand what we're discussing. Sort of like how you attempted to argue about what stagant water is. Don't get me wrong, it's OK to not know things - we all start somewhere. But at some point you have to listen to others and keep your mind open to learning new things.

Do this... find me a neutral party who says that SS is approved/fine for below the waterline use in boats that stay in the water. Prove me wrong.

But... how 'bout this for facts/experience... ABYC is an independent company that researches and specs/recommends BEST PRACTICES (remember that term from previous posts?). Manufacturers can choose to follow their guidelines and be an approved ABYC builder which means they're boats are built to a higher standard. ABYC says "no" to SS. I've also been in the marine industry for 35 years and own a boat dealership. Sure, anyone can do that last part - but it might just mean that I know at least a little bit about safe boating.

HERE'S THE BIG TAKEAWAY... Someone is telling you that it's not a good idea to use SS below the waterline for moored boats. Wouldn't the smart and open-minded person think "Hey, I have never heard that before. But maybe I should find out more about this so I don't risk my investment". Or, I could just keep my mouth shut, not try and educate, and let you deal with possible corrosion issues, or worse. But instead, you're arguing to use an inferior metal for a purpose it wasn't intended and trying to justify your point with guesses and inaccurate research just to save face.
 
Mustang65fbk said:
Your earlier comment was... "We've been telling you facts based on real life experience and knowledge. It would be beneficial to listen your elders ;)"... which I wouldn't necessarily really call facts or knowledge. It's your opinion, just like you've expressed multiple times as well as I've expressed multiple times.

You mentioned in the previous thread that.... "Bronze is a much more durable metal. SS will corrode underwater." which you then followed up with your very next opinion of... "I honestly don't know how well the SS would fair (or not fair). It's probably not (well, definitely not) something I would personally take a chance on. SS is also not "officially" approved for below the waterline. It's pretty well known in the marine industry that it's a no-go for SS. I don't know the answer, but if the boat sank due to a failed fitting... would the insurance company deny coverage due to installation of an unapproved item?" So which is it? Will it corrode or do you not know? You've said both statements or opinions and then go on to say it's not something you'd personally take a chance on. So exactly what kind of experience do you have with stainless steel below the water line when you haven't used it before, nor will you? That would be like me saying that a Chevy is a bad car when I've never actually owned one or driven one before. Also, you've never really proven anything like about how "SS is also not 'officially' approved for below the waterline." but again that's also just a blanket statement or opinion and I've yet to see you provide any sort of evidence or facts proving that statement. Along with the opinion you also mentioned about it being "pretty well known in the marine industry that it's a no-go for SS." Which just because that's your opinion or what you've heard, or read on Google, doesn't mean that it's at all accurate. Just like you're trying to dismiss my claims for what I've read on Google. Everything you've opinionated so far has been exactly that, only your opinion, with no links, facts or any sort of evidence included. Lastly, they do use Stainless Steel in the majority of underwater pipelines such as natural gas and so forth, which cover thousands and thousands of miles underneath the ocean. But I'm sure that won't change your mind, even though you admittedly have no experience using stainless steel under the waterline and I'm sure you'll continue to think the way you do, even though listening to us young bucks could prove to be beneficial at times as well ;)
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OH! SNAP!:p
 
DennisG01 said:
Most of what you've said I (or others) have already answered many times before so I'm going to skip over most of it.

No, it's not opinion. But if you would do your OWN research you would find the same things I am trying to educate you on. Grabbing a picture off of Grady's website showing ABOVE the waterline fixtures has no bearing on what we're talking about except to show that you don't yet understand what we're discussing. Sort of like how you attempted to argue about what stagant water is. Don't get me wrong, it's OK to not know things - we all start somewhere. But at some point you have to listen to others and keep your mind open to learning new things.

Do this... find me a neutral party who says that SS is approved/fine for below the waterline use in boats that stay in the water. Prove me wrong.

But... how 'bout this for facts/experience... ABYC is an independent company that researches and specs/recommends BEST PRACTICES (remember that term from previous posts?). Manufacturers can choose to follow their guidelines and be an approved ABYC builder which means they're boats are built to a higher standard. ABYC says "no" to SS. I've also been in the marine industry for 35 years and own a boat dealership. Sure, anyone can do that last part - but it might just mean that I know at least a little bit about safe boating.

HERE'S THE BIG TAKEAWAY... Someone is telling you that it's not a good idea to use SS below the waterline for moored boats. Wouldn't the smart and open-minded person think "Hey, I have never heard that before. But maybe I should find out more about this so I don't risk my investment". Or, I could just keep my mouth shut, not try and educate, and let you deal with possible corrosion issues, or worse. But instead, you're arguing to use an inferior metal for a purpose it wasn't intended and trying to justify your point with guesses and inaccurate research just to save face.
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yep....thread is festering nicely....:cool:
 
DennisG01 said:
Most of what you've said I (or others) have already answered many times before so I'm going to skip over most of it.

No, it's not opinion. But if you would do your OWN research you would find the same things I am trying to educate you on. Grabbing a picture off of Grady's website showing ABOVE the waterline fixtures has no bearing on what we're talking about except to show that you don't yet understand what we're discussing. Sort of like how you attempted to argue about what stagant water is. Don't get me wrong, it's OK to not know things - we all start somewhere. But at some point you have to listen to others and keep your mind open to learning new things.

Do this... find me a neutral party who says that SS is approved/fine for below the waterline use in boats that stay in the water. Prove me wrong.

But... how 'bout this for facts/experience... ABYC is an independent company that researches and specs/recommends BEST PRACTICES (remember that term from previous posts?). Manufacturers can choose to follow their guidelines and be an approved ABYC builder which means they're boats are built to a higher standard. ABYC says "no" to SS. I've also been in the marine industry for 35 years and own a boat dealership. Sure, anyone can do that last part - but it might just mean that I know at least a little bit about safe boating.

HERE'S THE BIG TAKEAWAY... Someone is telling you that it's not a good idea to use SS below the waterline for moored boats. Wouldn't the smart and open-minded person think "Hey, I have never heard that before. But maybe I should find out more about this so I don't risk my investment". Or, I could just keep my mouth shut, not try and educate, and let you deal with possible corrosion issues, or worse. But instead, you're arguing to use an inferior metal for a purpose it wasn't intended and trying to justify your point with guesses and inaccurate research just to save face.
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I'll leave it at this so as to not derail another thread.... I mean the Google definition of stagnant would be "standing still; without flow or current. brackish and foul from standing still. stale, sluggish, or dull from inaction." Which again, depending on your location, marina and so forth... there's a very strong possibility that your boat could rest in stagnant water for quite sometime. I think the bigger issue here is that you don't want to come off as incorrect or wrong to someone that's likely half your age. Same goes for the Vintage Mustang forums that I'm on... no one on there wants to be incorrect or have a 36 year year old tell them they're wrong either. I'm sure it'll continue to happen though, as is life.

Yes, some person I've never met before on a forum site is telling me it's a bad idea. Some person that admittedly has no experience with using stainless steel below the waterline is trying to give me advice because he's older than I am and has "been in the marine industry for 35 years". That's cool that you have that much experience, if that's actually true. That being said, a lot changes in 35 years, shoot a lot changes in a couple of years, and just because you didn't do something one way doesn't mean it's wrong or an "industry standard".

Here's a neutral third party that wrote up an article that talks about why Stainless Steel is the metal of choice for seawater pumps and that have been successfully used in seawater pumps in the North Sea since the early 1990's. It was one of the first couple of links that I saw when doing a quick Google search for "stainless steel in saltwater". I'm also not even sure if my scuppers are at the waterline or below... that being said, even if they are at the waterline or below it and these stainless steel scuppers only last 5-10 years then I'd still be very happy with them. I'm half tempted to order a set right now and submerge them consistently in saltwater and do a little scientific experiment at this point lol. Also also, I can't imagine that the stainless steel wouldn't last as long as the plastic scuppers or the ping pong ball style. Which, I'd rather spend $80 on the two stainless steel SI scuppers and hopefully get at least 5-10 years out of them as opposed to changing out the Attwood brand or the ping pong ball style ones every season or every couple of months at $15-20 a piece.

www.materialsperformance.com

Selecting Stainless Steels for Seawater Pumps

Pumps are routinely used to handle seawater. With the increasing demands for low maintenance and reliable operation, it is important that suitable corrosion-resistant materials are selected for pumps used in seawater.
www.materialsperformance.com www.materialsperformance.com
 
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I told myself I wouldn't post again to this thread and I didn't for a whole day!
Sea water pumps move sea water and that is aerated. Stainless likes air (oxygen). The issue is not corrosion on the outside per se but rather crevice corrosion that can occur when moisture gets trapped between ss surfaces ( including screws) and other surfaces but there is no air exchange. So the key to longevity is a good air AND water tight seal from sea water. If you install thru hulls and don't have sealant (not necessarily adhesive) ooze out a bit when snugged up (there is a trick to that also) and leave some sealant visible around the perimeter, moisture can seep under the flange. Same goes for the back side of the fitting
I have seen bronze thru hulls that were 70 plus years old and still usable. A 5 to 10 year life span for a hull fitting is unacceptable in my opinion. If you want to use SS thrus for under water applications where the vessel will sit in the water for extended periods, go ahead. Some of us wouldn't, some would.
 
Yes, your retroactive google definition of stagnant is correct. However, a more "still" area of water in a marina where a boat may be moored is NOT going to be stagnant. You're grasping at straws. Even if somone's definition of stagnant slightly differs from someone else's, you should be able to infer from the conversation what is meant (especially after we further explained it).

I'm always open to learning new things or being corrected if I'm mistaken. For example, Skunk pointed out SS underwater scoops and such. I had never seen these before so that was interesting to hear about. BUT, note the reference to "trailer boats".

It seems as though you haven't headed my recommendation to go back and re-read, or comprehend, as it seems you're completely glossing over what I've written and aren't taking the time to understand it: I have never used SS below the waterline because (1) It is not approved for that use, (2) Bronze IS a more durable metal, (3) I've only dealt with boats that are fully certiified and (4) I would not, personally, use an inferior product if someone is trusting me with their hard earned money. Again, AGAIN... Because I've never used it, I can't give a recommendation on how well it would fair for an in-water boat. What I DO know (facts) is that Bronze and Marelon are superior in this application. And, AGAIN, using SS below the waterline for a thru-hull fitting might be OK, depending on a number of variables. But it then becomes more important for the owner of the boat to do his due dilligence to keep an eye on it. For example, the gentleman, somehwere in a previous post, that said he is using it - I've seen enough of his posts to know that he'd be one to check on it (sorry - I forget who posted it, but I remember typing pretty much this same response about it before).

Seasick answered your raw water pump "attempt" at justification. We are not talking about sewater pumps - different application.

Mustang, in all seriousness and with no malintent.. just being straight with you... at what point do you suck it up and just admit that there's much more to this underwater thru-hull stuff than you knew about and maybe just zip your mouth and try and learn something? As I said before, it's totally OK to NOT know something - at one point NONE of us knew anything about this.

Oh, another reason I wouldn't use SS (I mentioned this briefly before) is that I don't want to chance an insurance company denying coverage for a sunk boat due to corrosion (although, also I said before, it's not like it's going to happen magically - it takes time - and with prudent monitoring it should be OK). While I don't know this for sure, I think it's a safe bet that an insurance company would try and classify this, at the least, under something like "lack of owner maintenance" and possibly "negligence". ESPECIALLY if somene paid me to do the work as then I'd be liable.

Remember, this discussion isn't about whether you can or can not do it. It's your rig - do as you wish. The point to my reluctance to let this go is education. As long as someone fully understands the risks, go for it. We're all big boys and big girls and can make our own decisions. But make those decisions as sound as possible, basing them on as much factual information as you can. One of those facts is that bronze IS better than SS.
 
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Gentlemen, really! I'd recommend ending this discussion. I know we all mean well, but ...
 
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Im a professional mechanical engineer, this article does a pretty good job of explaining the use of different stainless steel grades in various marine applications:


Somewhat off topic but, while we are on the subject of bedding thru hulls, here are some good articles on caulks:



www.practical-sailor.com

Mildew-resistant Caulks for Boats - Practical Sailor

Since 1974, Practical Sailor’s independent testing has taken the guesswork out of boat and gear buying.
www.practical-sailor.com www.practical-sailor.com
 
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