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

[BlueH2Obound]

Originally Posted by neilpride

As far as I know, with your foam airex core hull you need to cut the inner FG layer and dig into the foam until you find the outer layer, the problem here is that you may find yourself with a thin outer layer of FG, needing reinforcement and sealing the core.

Neil,

Our hull is 1" of Airex sandwiched by 1/2" of FRP on each side, so 2" thick in total. (I have cores that verify that)

I'm familiar with the process you outlined above, but one manufacturer specifically stated that with the Airex attached to the entire "outer hull" so to speak, it will attenuate or dampen the sound that you are attempting to transmit from the outer boundary layer (the outer portion of the hull).

Typically, when a manufacturer tells me that the product that they sell, which I was interested in purchasing, will not work in my application, I tend to take note!
I appreciate the input though, and if things change, I am still willing to give the technology a try!

[neilpride]

Originally Posted by BlueH2Obound

Neil,

Our hull is 1" of Airex sandwiched by 1/2" of FRP on each side, so 2" thick in total. (I have cores that verify that)

I'm familiar with the process you outlined above, but one manufacturer specifically stated that with the Airex attached to the entire "outer hull" so to speak, it will attenuate or dampen the sound that you are attempting to transmit from the outer boundary layer (the outer portion of the hull).

Typically, when a manufacturer tells me that the product that they sell, which I was interested in purchasing, will not work in my application, I tend to take note!
I appreciate the input though, and if things change, I am still willing to give the technology a try!

Absolutely, personally i have never trusted these things, i believe that pulses can do something on a solid hull. The funny thing about this story is that some brands of these gizmos claim they work on cored hulls.

I would like to see someone come back here and tell us if it works or not, until today nobody.

[Celestialsailor]

I'd like to see if one of these high profile Youtubers get sponsored by these hull protectors and do a review on them. Perhaps they would rather not.

[nortom]

I installed a 4 transducer system on my 46' Heritage West Indies, moored in Tyee marina Tacoma WA.
Had diver change zinks and clean max prop annually.
Ablative bottom paint 3 years in water, pulled for survey, hull was amazingly clean, prop had a lot of growth. I think it was worth it. The hull did not need pressure wash, when pulled 3 ago it required a lot of pressure washing.

[Stewie12]

The Boat Test video is very convincing. I would say properly installed - it works.

[Offshore58]

I don't get it.
You STILL have to haul and paint the bottom occasionally.
Like Roosevelt said
" There's an azz for every saddle "

[CaptTom]

Interesting. I'm just speculating here, but it seems sound would travel well through the metal of the shaft and prop. I'd be thrilled if I could install an ultrasonic device to just keep those from fouling, never mind the hull. Shouldn't be too hard to make something which tapped on the shaft at some magic frequency, once we know what that is.

Anecdotal evidence, especially from people who have reason to want to see it working, isn't definitive. But enough of them might get my hopes up.

[Checkswrecks]

I know the ultrasonics must work because some of the oilfield boats have begun using the systems and NOBODY is more oriented on the bottom line costs than most of those folks. EDT has been using it and they have some pretty big ships. A quick Google search found there are a number of manufacturers around the world.
Here are some case studies from one:
https://sonihull.com/case-studies/

That said, Fastbottoms job is safe because few recreational owners are going to pay for a system that needs a couple of haul-outs to amortize.

[Siberian Sea]

This has been the quest of most every sailor from the time that a hollowed out log first came to be used. Unfortunately for all of us it seems the best solution is one of two choices
A) leave you vessel on the hard
B) use the highest quality anti fowl coverage, apply it properly and the good old fashioned mask fins and snorkel to occasionally inspect and clean.
Yes, how we wish while humans seem to be on the cusps of creating true AI, self driving cars and instant global communications available for all we could find a way to keep the critters from growing on our vessels. Well this seems to be a tall order at the least and claims made by more then a few companies to have finally solved this problem seem dubious. However, if any of you desire to experiment with your $$$ and test out the new experimental drugs well..... go for it. As for myself I’m going to take the occasional swim under my boat and inspect things with brush in hand.

[fstbttms]

Originally Posted by Checkswrecks

I know the ultrasonics must work because some of the oilfield boats have begun using the systems and NOBODY is more oriented on the bottom line costs than most of those folks.

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.

[Jennyol]

I used an ultrasonic anti-fouling system on my boat about 8 years ago, it was used for around four seasons in Ireland. I was reluctant to put the boat in the water with absolutely no antifouling as I was looking for a good finish for racing so I applied one coat of a hard anti-fouling once a season and either lifted the boat to wash off the slime twice a year or asked a diver to give it a rub. So yes it worked in that we used a lot less anti-fouling and we washed it down much less than previously. Would I have been able to dispense completely with the anti-fouling? I don't know. Points to note: GRP sandwich construction. Would I buy i for another boat? Yes, using less anti-fouling is a good result in my view.

[Checkswrecks]

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.

More widely used in the coolers & RSW, yes, because those are the biggest bang for the buck. But despite your experience doing recreational boats in San Francisco, the systems are on working hulls in the Med, Europe, and Gulf. The oil rigs are also using them on the steel legs.

Another result: https://boattest.com/hull-shield-ult...fouling-system

[fstbttms]

Originally Posted by Checkswrecks

…the systems are on working hulls in the Med, Europe, and Gulf.

Provide evidence that ultrasonic systems are being used hull-wide on commercial vessels and I will happily eat my words.

[singlespeed]

They've been around for at least ten years. Notice how many actual positive reviews from the responders? Given the cost of annual haulouts, bottom cleaning and bottom paint in the Eastern Caribbean, payback would be two or three years.and a godsend to liveaboards. Yet I can only remember one boat with the installation. He was unhappy with it, but admitted he didn't even know if it was the system, the installation or the hull configuration that was the issue.

Testing conducted by any entity with even a hint of financial support from the product producer should always be treated with caution. It's like a peer reviewed scientific study sponsored by a company with a vested interest in the product. Funding for studies is notoriously tight, would you risk shutting down that source of funding? Ever notice how the peer reviews use the same pool of reviewers and never offer a conflicting opinion?

[xcebeuq]

Never heard of Hull Shield. Best you try Coppercoat (legal in California). Applied this to my boat in 2012, and it's still going strong. Without question an unqualified success.