New Product To Save Soft Decks

[Big Gip]

There is often a confusion between the strength of a material and its hardness. The claim that it is "hard as rock", probably also means that it is very brittle. That is a bad characteristic on a core. Plate glass is harder than steel, but it is a bad structural material.

I know this is an old thread but I used it on my Crownline boat and it works as advertised saved me $3000.

 

[upchurchmr]

Did you have problems with keeping the deck smooth?
Expansion of the foam was stated to cause "lumps" that needed to be pushed out before it hardened.

I hope you will keep us up to date on how it holds up.

 

[Big Gip]

Did you have problems with keeping the deck smooth?
Expansion of the foam was stated to cause "lumps" that needed to be pushed out before it hardened.

I hope you will keep us up to date on how it holds up.

No bumps hard like wood you just can't overfill and drill multiple holes so any extra just runs out the top on tape you put over the area for easy clean up and stand on it to keep it level

 

[Crusty Binnacle]

I stumbled across the website for injectadeck searching for a way to inject two part foam into the deck of an old sailboat. While I agree with the posts that the best way to insure structural integrity is to go through the labor intensive process of cutting open the deck and replacing the core it is a job that requires extensive time and an indoor location out of the weather. In my situation this is just not practical.

I purchased two part 8# urethane foam from FGCI in Florida and have been experimenting with it. I poured this stuff into an old sauce pan and let it harden. I cannot get it out now. Solid as a rock and seems to have stuck to the pot which has now become a conversation piece. When I tried to use the two part foam on the deck I simply could not get enough into the deck by just pouring. I vacuumed out as much of the rotten core as I could and used an allen wrench to create a cavity. Despite this effort the foam spread some under the deck but mainly produced nice beige looking mushrooms on top of the deck. Thus the idea of using a syringe came to mind which led to Google searches and discovery of the two part dispensing guns and the injectadeck site.

I am going to give the foam a try. The small area I did seems promising. The question I have now is whether to simply purchase a two part dispensing gun and empty two part cartridges (Atlas on Amazon) and use the urethane I have from FGCI or whether I should buy cartridges already filled perhaps trying injectadeck's magic potion.

 

[upchurchmr]

You can repeat the development that Injectadeck has already done or you can just buy something "proven".
My only concern is the long term wear or other consequences - unknown at this point.
Can you tell us the trade name of the 2 part foam you bought? Does it cure rigid or is it somewhat flexible?

I previously had some experience with a "structural" foam and the pieces I had showed good strength and stiffness - but we didn't work them like a boat.
Let us know what works.

 

[Crusty Binnacle]

You can repeat the development that Injectadeck has already done or you can just buy something "proven".
My only concern is the long term wear or other consequences - unknown at this point.
Can you tell us the trade name of the 2 part foam you bought? Does it cure rigid or is it somewhat flexible?

I previously had some experience with a "structural" foam and the pieces I had showed good strength and stiffness - but we didn't work them like a boat.
Let us know what works.

 

[Crusty Binnacle]

The containers do not provide any clue as to the trade name. They are simply labeled as FCGI products, Fiberglass Coatings Inc. St. Petersburg FL. The 8# stuff I bought cures rigid. You can press very hard on the cured product and it does not dent. I am sure that if you smacked it with a hammer it would. The excess that came up out of the deck I cut off with a hacksaw blade.
Thanks for the response.

 

[PAR]

FGCI formulates it own mixtures, purchasing raw stocks from the usual south eastern USA sources. They have a few different density polyurethane (2 part) liquid foams and I've used them before, but now have a cheaper supplier of similar stock. As is typical of an 8 pound foam, it's pretty dense and a little up on the structural application list, but it can be dented and has the usual limitations seen with this type of foam. It's best applied inside a space that is epoxy sealed, preferably with a still green second coat. It does bond better this way, which is one of the weak points to consider with this approuch.

 

[Outobie]

Would this product be advisable to inject into stringers?

I’d love some thoughts and feedback on the below email exchange I had with my boat manufacturer below.

I’m trying to figure out what if anything should be done to the coring in my Stringer’s. The two middle stringers sound hollow while the two outer stringers sound very solid.

Should I be worried that my motor mounts seems to be screwed into nothing more than thin fiberglass?

Thanks for any suggestions


Oh, sorry for the formatting but for the below email exchange to make sense read from the bottom up
.........;.…
I guess my initial question is why? Is there any evidence that anything is coming adrift?

Anyway, other methods are aluminum plates that are laminated into the stringers, then drilled and tapped for mounting bolts. This is not something all that easy to do as a retrofit. As a retro, it would be far easier to install what we call toggle bolts; these are simply big pins made of round stock such as 1" free cutting brass, drilled and tapped for whatever bolts the mounts require. The pins are pressed into holes drilled athwartship through the stringers, then the mounting bolts thread into the tapped holes. Simple, strong, and very effective.

Scott

-----Original Message-----
From: John Knott [mailto:jknott@ix.netcom.com]
Sent: Thursday, September 28, 2017 11:11 AM
To: Scott Bytwerk <SBytwerk@s2yachts.com>
Cc: Kimberly Vargas <kvargas@tiarayachts.com>
Subject: Re: Portlight parts help request 56006 39817

Ok that's very helpful

Perhaps then I will look at alternative methods of securing the motor mounts to the stringers rather than the lag bolts that are there now.

You mentioned that there have been other methods used of attaching motor mounts. I'm thinking about constructing a metal shoe that fits over and around the stringer and then bonding it to the stringer.

I'd love to know what other methods the smart folks at the factory use

Thanks
John


Sent from my mobile device
443-676-1358

On Sep 28, 2017, at 10:55 AM, Scott Bytwerk <SBytwerk@s2yachts.com> wrote:

Conceivable, yes. There have been many methods used to nail engines down, simple lag screws probably being most prevalent for a good number of years; those, obviously, rely pretty heavily on whatever it is into which they're driven. I'm going to refrain from telling you that yours are perfectly fine, that's simply not a diagnosis that can be made from here; only hands-on examination can make a valid assessment.

While not exactly confidence-inspiring, sounds like nothing major. We don't have drawings or lamination schedules that will define the actual stringer construction in this boat, but I can say that it's common to have mahogany blocks laminated into them beneath the engine mount locations, but not extending much either fore or aft. Guess my point there is that it's possible that there's not such a block under the deck supports, but there is under engine mounts.

This doesn't really help much, I'm aware, but this is pretty easy to delve into in order to properly assess present condition.

Best,

Scott

-----Original Message-----
From: John Knott [mailto:jknott@ix.netcom.com]
Sent: Friday, September 29, 2017 8:10 AM
To: Scott Bytwerk <SBytwerk@s2yachts.com>
Subject: RE: Portlight parts help request 56006 39817

The motor mounts appear to be fine. There is an aluminum pole that sits on top the stringers between the engines and supports the underside of the engine hatches. All the screws holding the support pole t to the stringers pulled out just from leaning against it while working on the engines. I looked into the holes and there was just empty space with nothing for the
screws to bite into.

While working on that pole, it got me thinking that the engine mounts are also just resting on the stringers without anything really securing them.
I'm not an engineer but that sounds like it could be trouble if the motors shift for some reason.

I'm putting a good bit of money into restoring the boat, I'd like to not have it come apart and quite frankly I don't have the expertise to know what's important and what isn't so I ask questions when I see things that I don't have a good understanding of.

…..........

Having been with S2 for nearly two decades, I can feel really confident in telling you sight unseen that your stringers are just fine. Our stringers are constructed using what's commonly refered to as "box" design, in which there is a substrate of wood or foam or both, over which heavy layers of fiberglass are placed. Once cured, the substrate is irrelevant: the strength is in the glass, the substrate only needed to be there long enough to support it while curing. It's possible to compromise one of our stringers, but generally that would be the result of severe impact rather than biodegrading core. Does this help?


Best,


Scott

 

[Sean Derek]

Injectadeck is a reasonable, perhaps temporary, solution to a limited range of problems.

They should have done a better job describing their product and its limitations. Likewise, representatives of the company should be patient and informative participants in online discussions,

Let's look at how I used the product. I purchased a 1975 43' Drifter houseboat for $6500 last year. It was in good condition for its age with a couple of 1' diameter soft spots on the upper deck and one 1' diameter soft spot on the main deck.

When I bought the boat my plan was to have fun with it for 3-5 years, nothing more. Given my plan, I probably could have ignored the soft spots. Their progression were likely to be slow and they didn't represent much of a safety risk.

I understood what a "proper" repair would involve. Instead, I went with the band aid approach and I'm pretty damn happy with it. Injectadeck exceeded my low expectations. My soft spots are gone and they handled light traffic this summer without any noticeable degradation. In high traffic areas, it's the flex caused by foot traffic that is the primary cause for soft spot growth. Stop the flex by eliminating the soft stop and you've bought time. I also addressed likely areas of infiltration including recoating the upper deck.

This solution made sense for me. I wouldn't have chosen this solution for my $75K sailboat in perfect condition that I see myself owning for 20 more years.

 

[riskmore]

Is this thread still alive? I have a balsa core sailboat hull repair below the water line. Because of an accident a fracture of both skins opened up where the forward keel blends into the hull so the curves are very complex. Its drying out on the hard now

the core is lost for 50mm each side of a 1 meter crack and while well connected to the inner skin its separated from the outer for another 50cm. working overhead building 8 ply is the most professional option but I'm thinking about cutting the inner section with its core away then rebounding the section with resin and vacuum then patching the seams.

The easiest option would be to repair the fractures then inject resin filling the delaminated surfaces and then fill with some fancy expanding foam the area without any core.

Any opinions?

 

[upchurchmr]

There never was good mechanical properties shown for the system that started the thread.
No question you could fill the void, but would there be good strength for a long time?
If you try to put expanding foam between two skins, be very concerned with the pressure of the foam causing damage.

Good luck.