Anyone with experience using "hull shield" ultrasonic antifouling system?

[Icarus]

Originally Posted by mvweebles

Do you have actual experience that it doesn't work? Or just conjecture "if it seems to good to be true....?" I'm mildly skeptical, but found the video interesting. BoatTest has a patina of coziness with marine companies they review, but they are worthwhile and they do have a reputation. In the video, they show small patches of isolation from ultrasound where growth was present made sense and lent credibility. And then the SailMagazine article someone else posted was a mild endorsement.

Just saying "I'm a marine professional and I know better" is interesting - you're entitled your opinion, but without more, it doesn't carry much weight.

I would suggest try it and find out ...after all marine experts have a reputation to uphold...

[fstbttms]

Originally Posted by Icarus

I would suggest try it and find out ...after all marine experts have a reputation to uphold...

One doesn't have to go to the moon to know it isn't made of green cheese

[Lee Jerry]

Let me quickly start by saying the notion that ships do not have issues with hull biofouling is just patently absurd. It’s so ignorant that it doesn’t warrant further response. I mean, you see some stupid stuff on the interweb, but that’s the best in quite a while. But anyway...


As far as the effectiveness of ultrasonic antifouling (in general, not the brand in the OP), just based on this thread the conclusion has to be YES it CAN work. This is clearly demonstrated by the following posts: #75 by hezi973, #79 by norton, #85 by fstbttms (yes, I’ll explain), and #107 by molly1. There are others too and also some links. Are these people wrong, lying, shills for the industry? I take them at their word. YMMV.

This is not to say that any particular installation WILL work. As with any system or product, there are a myriad of ways that things can go wrong: poor design, improper installation, wrong setup, etc., etc.

Also, some of you seem to have some unrealistic expectations. If you require no painting and no growth for decades on end, you’re living in some fantasy world. If we come back to earth and use some common sense and a reasonable definition, like maybe something in line with what the vendors actually claim it does, then again yes they work. I believe those claims are (IIRC): used in conjunction with appropriate bottom paint, it will inhibit some growth and retard other growth, resulting in reduced bottom cleaning, reduced haul outs, longer paint life, and what growth there is cleans off easier. I think those posts (and others) demonstrate that performance.


Here's post #85:

Originally Posted by fstbttms

I guarantee that in the commercial shipping world, the use of ultrasonic systems is limited to specific critical areas of the vessel, such as the sea chest and box coolers. These devices are not being used to keep the entire hull clean, because they are not capable of keeping the entire hull clean.

So you admit the systems are installed in sea chests; do they work there? Or are the owners wasting their money? If they work in sea chests, why wouldn’t they work on the hull? It’s the same water and the same organisms. The only significant variable might be less sunlight in the piping (at least compared to the WL and sides, less so the bottom). Why, specifically, would they not work on the hull if they do work in the sea chests?

I posit that they could/would work on the hull but commercial vessels are probably not using them for hull protection for some other reason(s), like say, simply because it isn’t economically beneficial. Here are a few possibilities for why this might be:

- Ships have to dry dock on a fairly strict schedule (varies depending on vessel type), so if you can’t benefit from the potential extended time between haul outs, you’re missing one of the major cost saving opportunities provided by the ultrasonic system.

- If you have a paint system that already provides “adequate” protection between these dockings, that benefit may be reduced too. (Even if maybe it could help reduce growth somewhat and lower fuel consumption in between.) As previously mentioned, many commercial ships are operated continuously and are only in port for cargo operations, thus allowing the paint to function properly with regular “scrubbing” at sea.

- Some ships are big. That means the ultrasonic systems would have to be “big” too (lots of transducers, lots and lots of cabling). In addition to the up-front cost, the weight might translate to lost cargo capacity (so even if relatively small, could add up to be significant since it’s on every voyage), thus negating some of the other savings. Not sure how the system scales.

- Some vessels aren’t too concerned with frictional resistance, so wouldn’t benefit nearly as much. For example, a harbor tug whose primary mission is high bollard pull, and even when transiting “at speed” is only doing about 10 kt and digging a large hole in the water while doing so (i.e. has proportionately higher wave making resistance).

These are just a few I thought of now; I’m sure there are more. Regardless, none of them mean the ultrasonic system "is not capable," just that the benefits are reduced or negated, so the economics don't work out as well. It's quite possible that there are some commercial vessels that could benefit (irrespective of that first bullet).

[fstbttms]

Originally Posted by Lee Jerry

Let me quickly start by saying the notion that ships do not have issues with hull biofouling is just patently absurd. It’s so ignorant that it doesn’t warrant further response.

Who said ships don't have issues with biofouling?

[Lee Jerry]

Originally Posted by fstbttms

Who said ships don't have issues with biofouling?

I was referring to this:

Originally Posted by BBill

...I was in the merchant marines in the Viet Nam era and those ships went yrs and yrs between haul outs and had very little growth.

[fstbttms]

Originally Posted by Lee Jerry

I was referring to this:

I guess you like to twist words. Because going a long time between haulouts and bottom jobs back in the day when merchant vessels could use tin-based paints isn't the same as claiming ships don't have issues with biofouling.

Originally Posted by Lee Jerry

Let me quickly start by saying the notion that ships do not have issues with hull biofouling is just patently absurd. It’s so ignorant that it doesn’t warrant further response. I mean, you see some stupid stuff on the interweb, but that’s the best in quite a while. But anyway...


As far as the effectiveness of ultrasonic antifouling (in general, not the brand in the OP), just based on this thread the conclusion has to be YES it CAN work. This is clearly demonstrated by the following posts: #75 by hezi973, #79 by norton, #85 by fstbttms (yes, I’ll explain), and #107 by molly1. There are others too and also some links. Are these people wrong, lying, shills for the industry? I take them at their word. YMMV.

This is not to say that any particular installation WILL work. As with any system or product, there are a myriad of ways that things can go wrong: poor design, improper installation, wrong setup, etc., etc.

Also, some of you seem to have some unrealistic expectations. If you require no painting and no growth for decades on end, you’re living in some fantasy world. If we come back to earth and use some common sense and a reasonable definition, like maybe something in line with what the vendors actually claim it does, then again yes they work. I believe those claims are (IIRC): used in conjunction with appropriate bottom paint, it will inhibit some growth and retard other growth, resulting in reduced bottom cleaning, reduced haul outs, longer paint life, and what growth there is cleans off easier. I think those posts (and others) demonstrate that performance.


Here's post #85:
So you admit the systems are installed in sea chests; do they work there? Or are the owners wasting their money? If they work in sea chests, why wouldn’t they work on the hull? It’s the same water and the same organisms. The only significant variable might be less sunlight in the piping (at least compared to the WL and sides, less so the bottom). Why, specifically, would they not work on the hull if they do work in the sea chests?

I posit that they could/would work on the hull but commercial vessels are probably not using them for hull protection for some other reason(s), like say, simply because it isn’t economically beneficial. Here are a few possibilities for why this might be:

- Ships have to dry dock on a fairly strict schedule (varies depending on vessel type), so if you can’t benefit from the potential extended time between haul outs, you’re missing one of the major cost saving opportunities provided by the ultrasonic system.

- If you have a paint system that already provides “adequate” protection between these dockings, that benefit may be reduced too. (Even if maybe it could help reduce growth somewhat and lower fuel consumption in between.) As previously mentioned, many commercial ships are operated continuously and are only in port for cargo operations, thus allowing the paint to function properly with regular “scrubbing” at sea.

- Some ships are big. That means the ultrasonic systems would have to be “big” too (lots of transducers, lots and lots of cabling). In addition to the up-front cost, the weight might translate to lost cargo capacity (so even if relatively small, could add up to be significant since it’s on every voyage), thus negating some of the other savings. Not sure how the system scales.

- Some vessels aren’t too concerned with frictional resistance, so wouldn’t benefit nearly as much. For example, a harbor tug whose primary mission is high bollard pull, and even when transiting “at speed” is only doing about 10 kt and digging a large hole in the water while doing so (i.e. has proportionately higher wave making resistance).

These are just a few I thought of now; I’m sure there are more. Regardless, none of them mean the ultrasonic system "is not capable," just that the benefits are reduced or negated, so the economics don't work out as well. It's quite possible that there are some commercial vessels that could benefit (irrespective of that first bullet).

Commecial shipping interests spend millions of dollars per vessel per annum on fuel. If a permanently installed anti fouling system that lasted for years could reduce fuel consumption even marginally, it seems likely that it would be in use. But the bottom line is, you are speculating. You don't have any real knowledge about why commercial vessels don't use ultrasonic systems ship-wide.

[Lee Jerry]

Originally Posted by fstbttms

Commecial shipping interests spend millions of dollars per vessel per annum on fuel. If a permanently installed anti fouling system that lasted for years could reduce fuel consumption even marginally, it seems likely that it would be in use.

Yes, if the cost-benefit ratio or ROI works out. I don't have enough information to figure that out in this thread. Do you?

But the bottom line is, you are speculating.

Yes, out loud so you can see my thoughts (not just making proclamations). They seem reasonable to me, but feel free to make a contrary argument.

You don't have any real knowledge about why commercial vessels don't use ultrasonic systems ship-wide.

Well, I've never owned or operated a commercial vessel, and never had to consider installing one, so in that respect you are correct. But otherwise, I would have to disagree with you. I may have a little more than you think.



So:
1. On what do you base your claim that ultrasonic antifouling "is not capable" of whole-ship hull protection on commercial vessels?
2. Does (can) ultrasonic antifouling work on yachts?

[fstbttms]

Originally Posted by Lee Jerry

1. On what do you base your claim that ultrasonic antifouling "is not capable" of whole-ship hull protection on commercial vessels?
2. Does (can) ultrasonic antifouling work on yachts?

In answer to both your points- If it could, it would. Ultrasonic anti fouling remains on the fringe of the recreational boating industry, after decades in the marketplace. And if it could reduce fouling on ships hulls in any sort of meaningful way, they'd be using it. But they don't. Both conditions indicate that it cannot do what its manufacturers claim, IMHO.

[Lee Jerry]

Originally Posted by fstbttms

In answer to both your points- If it could, it would. Ultrasonic anti fouling remains on the fringe of the recreational boating industry, after decades in the marketplace. And if it could reduce fouling on ships hulls in any sort of meaningful way, they'd be using it. But they don't. Both conditions indicate that it cannot do what its manufacturers claim, IMHO.

Well in the case of yachts (to keep it more on topic), evidence has been presented in the posts I referenced above (and some others) that it does work. I'm sorry it's not in the numbers or time frame you require.

[fstbttms]

Originally Posted by Lee Jerry

...evidence has been presented in the posts I referenced above (and some others) that it does work.

Then please explain why almost nobody has a system installed on their boat.

[mvweebles]

Originally Posted by fstbttms

In answer to both your points- If it could, it would. Ultrasonic anti fouling remains on the fringe of the recreational boating industry, after decades in the marketplace. And if it could reduce fouling on ships hulls in any sort of meaningful way, they'd be using it. But they don't. Both conditions indicate that it cannot do what its manufacturers claim, IMHO.

Actually, according to at least one of the links provided upthread, ultrasonic antifouling increasingly common, especially on cruise ships.

Comments from Steve D'antonio - sees effectiveness in limited, small area usages such as keel coolers.

https://www.morganscloud.com/2020/04...comment-292040

[Lee Jerry]

Originally Posted by fstbttms

Then please explain why almost nobody has a system installed on their boat.

Not really my job...

...I mean, if I could explain why people do (or don't do) the things they do, I'd probably be a lot wealthier and more powerful...

...or maybe their bottom guy talked them out of it.,,




...or maybe people are idiots...

[fstbttms]

Originally Posted by Lee Jerry

Not really my job...

It seems we both agree that ultrasonic systems are in very limited use on recreational vessels. I claim that the reason for that is because they don't perform well. You claim... well, you won't (or can't) provide a reason for that. Apparently it's not your job to defend your argument. OK, good to know.

[Lee Jerry]

Originally Posted by fstbttms

Then please explain why almost nobody has a system installed on their boat.

Originally Posted by Lee Jerry

Not really my job...

...I mean, if I could explain why people do (or don't do) the things they do, I'd probably be a lot wealthier and more powerful...

...or maybe their bottom guy talked them out of it.,,

On a more serious note, I will add that people, especially Americans, are not particularly good at looking long term and figuring out that they would (could / might) come out better in the long run. They just see the higher initial cost and run away.

[Lee Jerry]

Originally Posted by fstbttms

It seems we both agree that ultrasonic systems are in very limited use on recreational vessels. I claim that the reason for that is because they don't perform well. You claim... well, you won't (or can't) provide a reason for that. Apparently it's not your job to defend your argument. OK, good to know.

I have no idea how limited their use is or isn't. But the point is, that even if their use is limited, that is not (necessarily) an indication that they don't perform well. That would have to be demonstrated, not just claimed. It could be that, or maybe it's some other reason. Maybe poor marketing. Maybe people are bad at finances. Maybe something else. Maybe some of all of it. Again, how popular something is has no bearing on whether or not it works as claimed.