Question about alternatives to stringer/transom replacement material

[Weirdnerd]

I have seen that the vast majority of repairs and restorations are done using traditional methods, using plywood, fiberglass and polyester resin, in researching I have found three materials that are a little pricier, but they offer vastly longer durability and water resistance.

My question is: has anyone used this products, and what is your opinion regarding use, ease of work, price and results?...real life use, I mean real life results under real life conditions.

the products are the following:

Thermo lite board: http://www.spaceagesynthetics.com/fi...ies%200932.pdf

3M reinforced polyurethane foam: http://multimedia.3m.com/mws/media/8...e%20Foam%20fly

Coosa composites blue water Board: http://www.coosacomposites.com/bluewater.htm

 

[DeepBlue2010]

I used Coosa 26 (not on my own boat). It is a good product but if your application doesn't utilize or benefit from what a product like this has to offer, you will be spending more than you should with little or no return. If $$ is no issue, go for it. If all you need is to secure your structural elements (stringers, transom and bulkheads) from possible water intrusion, use the traditional building materials (wood) the right way. Boats don't rot simply because they are made out of encapsulated wood. They mostly rot because of bad building techniques and craftsmanship from the factory

 

[Kyle W]

I agree that most boats rot from poor building methods. I have seen 45 year old wood core panels as dry as the day they were made. Likewise i have seen much younger boats fail from screw holes and rigging tubes that werent sealed.

I dont have any experience with any of the materials you posted. I do have some knowledge of the products from sales reps and other rebuilds. Coosa bluewater 26 is a structural material. You can use it as a core material in the stringers and transom. Decks and topside can be built out of 8-10 lb density like the thermo lite board.

I have used Polyumac Inc. Air-Comb from Composites One for a deck. Its a very versatile material and supper light weight.

 

[79_banshee]

No Title

This is a pick of my stringers in a 79 glastron ft 150. I do believe that this is the way factory made it cause it don't look like the floor was ever touched. They didn't seal the wood very well with Fiberglass or I probably wouldn't be doing the stringers. The keel has not rotted yet but was very waterlogged. If they didn't miss two areas I'm sure it would have been dry.

 

[Weirdnerd]

Interesting, I found a couple of spots about 3x5 inches of soggy wood on my boat stringers ( right side), and I was wondering about those materials to do the replacement, I am planning to use epoxy ( west system) as I am very familiar with epoxy resins, and only a little about polyester to do very small non structural jobs, I like to have the luxury of time to do my repairs without racing against time. for the time being I will be doing a couple of scarf repairs on those areas, as winter is almost here and I would like to have the boat for spring. SO far I got a new water pump and I have to drain the fuel tank , change oil and seals on the engine and other small repairs will be cosmetic ( remove the vinyl decals on the dashboard and make sure electrical will work.

 

[ondarvr]

They all work, not hard to cut or shape, if you want to spend the money they're good products. It sort of depends on how long you plan to keep the boat, more than 15 years and it may pay off.

 

[Scott Danforth]

look at it this way. the factory slammed together wood with a stable gun and plastered it with pre-pregged cloth and did it in about 3 hours. it lasted about 30 years for most cases

taking a bit of care, using the same materials, no reason another 30-50 years isnt fesible. why would you need to spend an extra 2-3 times over the price of wood.

99% of the boats restored will be sold along the way for a bigger boat.

as indicated by ondarvr, deepblue, and others. you can spend more on other products......but why waste the money

 

[JASinIL2006]

If you do a search on Coosa on this forum, you'll likely find a number of topics that deal with it. Many of us have considered it - I know I did - as we started our own restorations. Ultimately, I decided it just wasn't worth the cost and the extra hassle to get the stuff.

 

[RCNelson]

If a person uses a composite material, instead of wood for the stringers, does that mean it would not have to be encapsulated with fiberglass? Could a person simply epoxy it to the hull and install the deck on top of it. Seems to me that would save a LOT of labor and also some costs.

 

[Weirdnerd]

I have been looking at the master craft way of building stringers on their boats and I think that is a very nice idea, they are basically box spars glued to the hull, not that I will undertake the labor to make that, but it left me thinking a lot about it: I will fix the issue next year after enjoying the boat first. So far I am rebuilding the engine accessories...Just replaced the water recirculating pump, I am in the process of replacing the upper and lower thermostat housing, will remove the lower unit and give it a do over as well as I just ordered the impeller, tomorrow I am removing the fuel tank and going to clean it very well and use fuel tank sealant and paint it.

I had a "funny" moment when I received the thermostat housings, started cleaning them with acetone and all the paint just dissolved, so I had to clean them completely and repainted them with fuel resistant epoxy primer ( MIL PRF 23377 epoxy primer), they will outlast the rest of the engine...hehehe

 

[Weirdnerd]

Will post more pics tomorrow.

 

[friderday]

I am strongly considering coosa bluewater 26, 1.5" for transom in my newest restore(sorry no thread)...I think this is a no brainer IF, and this is a big IF, money is not an issue. A more perplexing dilemma, for my train of thinking, is the stringers & bulks. Some have suggested core cell foam, nidacore, or divinicyl as more reasonably priced options. My only concern is that all 3 of these have crappy screw retention and compression ability. So if I were to use one of these products, how would I screw down my deck, or center console, or leaning post? This returns me to either the traditional plywood stringers, diligently encapsulated in glass/resin and a prayer, or to the original coosa 26(as the 15 doesn't have good screw retention either). So coosa 26, although pricey, may be an option for transom...but considering the same for stringers could be a financial challenge to most. On the other hand, it seems that we get sucked in by the mentality, "well if I'm gonna spend that much on a transom that won't rot, and then put wood stringers, what did I accomplish?" Using coosa for transom and then plywood for stringers seems like an oxymoron, half arse plan, but what do I know? If it was cheap & easy, heck, everyone would be doing it!

 

[Woodonglass]

The question about Transom and Stringer Materials has been discussed "Ad Infinitum" her on the forum. Composites both premade or pour in have all been discussed and tried. They WORK!!! Not doubt about it but as also has been stated so does Good Old Wood! IF you are the kind of person that doesn't do a good job on maintenance and care then composites would be a good investment IF you plan on keeping the boat for 20-30 years. Most people don't. If, on the other hand, you DO take good care of your boat, and keep her tilted and covered when not in use, then a properly fabricated and installed wood transom will last as many years as the composites. My plywood transom is 55 years old and still as good as new. Bottom line, is...It's your boat and your money so do what you feel is best for you.

 

[Weirdnerd]

There are many ways to accomplish screw retention without having to go through a core material, at work I use normally a product line called " Click bond" they have studs, nutplates, plugs and a wide variety of stand offs and gadgets to attach composite parts without having to damage the laminates. if you were to use niacore or divinicell can and are used normally to stiffen structural elements on aircraft, and they work very well, the trick is to use hardware through a potted section of the core : make a hole, remove the core 1/4 of an inch around the hole, fill the hole with epoxy and microbaloons or Cabosil, drill it again and glue a nutplate at the other side of the attaching section, some other method is to glue an "insert" using the same method for the hardware to go through without compressing the laminate


https://www.youtube.com/watch?v=Xl_zYF7l-1g

https://www.youtube.com/watch?v=Aw0jfVpKgI0

 

[friderday]

I'm with wood.....and Wood! Good advice, Mike...as always