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Coosa Composite Board - Bluewater 26

As low as $110.31
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Key Features:

  • Great Decking and Transom Alternative - Do It Once - Do It Right!
  • Strongest and Stiffest Composite Panel with the Absolute Highest Strength-to-Weight Ratio
  • Consists of Polyurethane foam filled throughout with layers of continuous strand glass and woven fiberglass
  • Over 30% lighter than Plywood with equal superior structural integrity!
  • Absolutely No Water Rot! Mold, Mildew and Algae Resistant
  • 30% to 45% lighter than plywood
  • NO water rot or insect infestation
  • Less than 1% water absorption
  • Mold, mildew & algae resistant
  • NO Special Maintenance Required
  • Sanded for easy lamination
  • Easily fabricated with standard tools
  • Superior resiliency and endurance
  • Transoms
  • Decking
  • Swim Platforms
  • Sun Decks
  • Seating
  • Bench Cores
  • Bulkheads
  • Engine Covers & More!

Coosa Board Frequently Asked Questions

When replacing plywood decking, what thickness should I use?

The Short Answer

Bluewater 26 Coosa Board can be used as an exact replacement for any plywood decking as long as you use the same thickness installed in the same way (i.e. if your plywood was glassed over, so should your Coosa).

The Long Answer

If for some reason you would like to use a different thickness or install the material in a different fashion, there are a variety of things to consider such as:

  • What is the current span width between supports?
  • How is the material installed? (If glassed over, the fiberglass is adding additional rigidity)
  • Is the load spread over a panel or a point load?
  • How is the panel supposed at the edges? Is there a 1/2", 1"...6" overlap?
  • Does the panel need to support an impact load? (Think 300 lb guy jumping off a 5 ft. dock with an ice chest full of beer!
  • How is the board installed? Rigid bonded at the edges or free floating?
All of these factors need to be taken into consideration before a decision can be made on thickness. Boat builders pay a team of engineers to take all of these complex factors into consideration. We therefore recommend leveraging their decision and using the same thickness installed in the same fashion whenever possible.

If you are set on changing the thickness and installation method, please keep in mind that if you make changes that decrease the structural integrity of your deck you will need to make this up somehow. (i.e. if you choose not to fiberglass both sides of the floor, even though your original plywood was, perhaps you need to add additional braces of a stiffener to your span width).

How do I install Coosa Board?

Coosa Board can simply be installed as you would plywood or material being replaced using the same methods and tools.

How do I cut Coosa Board? Can you cut the board to my specific size and shape?

You can cut Coosa Board using any standard woodworking tools. Please make sure to take the same precautions (eye protection, gloves, dust mask, etc.) as you would when cutting plywood.

We are happy to cut your Coosa Board to any required size and shape. Please note that an engineering charge and/or a cut charge may apply depending on the shape of your pattern.

How do I use Coosa Board for decking?

You simply install the Coosa Board as you would plywood using the suggestions above. Many people have simply installed the Coosa Board and adhered carpet directly over the Coosa Board using their favorite adhesive.

Do I have to fiber-glass in the Coosa Board?

You do not have to fiber-glass in the board to prevent absorption of water/liquid; however, glassing the board also adds strength. Therefore, if you choose not to glass in (and your original decking was glassed), you will have to compensate for that loss of strength.

Is Coosa Board UV Stabilized?

Coosa Board is not UV Stabilized. With time, the boards will change color when exposed to sunlight. We recommend that Coosa Board be either glassed over, carpeted over, or painted with a latex or enamel paint.

What types of resin are compatible with Coosa Board?

All typical marine resins work with Coosa Board, including epoxy, vinyl ester and polyester resins.

I see elsewhere online a Nautical Coosa Board. What is the difference and is it available?

Bluewater Coosa Board contains continuous strand glass and woven roven fiberglass, while Nautical Coosa Board only contain continuous strand glass.

Therefore, Bluewater is significantly more rigid and is recommended for all structural applications. If your application is not structural (bulkhead, cabinet, etc.) then Nautical may be a good alternative and more cost effective than Bluewater. Boat Outfitters does not currently carry Nautical Coosa board; however, please let us know if you are interested as we always adjusting our inventoried material.

How does Coosa Board Ship?

It depends on the size piece you are ordering. If you order either a full sheet (96" x 48") or a half sheet (48" x 48"), it will have to ship freight. We are happy to get freight shipping quotes if you will send us your zip code and destination type (either commercial or residential). Please note that with freight shipping commercial addresses are significantly less expensive to ship to.

If you are ordering a third of a sheet (48" x 32"), then your piece can ship UPS. UPS shipping costs will vary based on location but will always be considerably less expensive than freight shipping.

Note: For the price conscious customer who needs a full sheet, please consider having your sheet cut into thirds. (3 pieces - 48" x 32"). This will allow your order to ship UPS and save you shipping costs.

When will my order ship?

Everything listed on the website is in stock available to ship. Our standard lead time is 2-3 days for Coosa Board.

Frequently Bought Together

  1. Coosa Composite Board - Bluewater 26
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  3. Stainless Steel T-Nut
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  5. Tuff Coat Rubberized Non Skid Coating
Total price: $0.00
  • This item: Coosa Composite Board - Bluewater 26 $110.31

5.0 / 5.0
10 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Great product, and great service!
First time using Coosa board. I like this product! Easy to machine and work with. Will order again.
Fast delivery as well.
March 18, 2019
4 weeks ago
Impressive product, easy to work with
So far so good. This 24' Sundancer pontoon from 1991 had a plywood transom that was beginning to rot on the bottom where it had the most contact with water. I had to have the motor rebuilt this winter so it was the perfect opportunity to also replace the damaged transom. I purchased a 1/3 sheet of the coosa 26 bluewater after a couple calls to the nice folks at boatoutfitters to ensure that this was a good application for the board. They insisted that this is an ideal application. My old transom was 1 7/8" thick so I bought a 1" thick sheet of coosa, cut out two pieces to match the old transom by tracing the old piece and I cut them out using a 6.5" cordless circular saw. Per the recommendation of the agents at boatoutfitters I purchased a sheet of fiberglass cloth and resin (i used a bondo kit from the hardware store for $12) I cut the cloth about 1/2 smaller than my pieces of coosa, coated one panel with resin, layed down the cloth then saturated it with resin. Next I coated the opposite piece of coosa with resin and sandwiched the pieces together. I placed the group flat and put weights on them overnight. The next night I coated the entire piece with resin and let dry. Once dry it was time to try installing the board. Lining up the mounting holes (with compound angles) was a challenge, but I figured it out by drilling the top holes by eye then I marked the remaining holes with my drill bit with only the top two bolts inserted into the mounting brackets. I then removed the bolts and board and used the angles in the old transom as a guide (the original board had to be slid off the edge so the holes would line up properly, but the drill bit would maintain the original angles and placement) this method got me super close and required only minimal drilling to ensure the bolts would line up. The last part was fitting the top cap. Because I now had a full 2" transom and the original was only 1 7"8 I had to trim a small amount from the top face of the new board using the table saw and I rounded the edges with a file. The end result is pretty fantastic. The board was very easy to cut and drill. Everything is through bolted and the motor mounts are backed with a thin piece of stainless. I hope this is the last transom I ever have to put on this boat and I am very anxious to get it back in the water with the fresh parts and motor!
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March 7, 2019
1 month ago
Review sent in previous email.
New Coosa board transom
Old rotted plywood transom
January 30, 2019
2 months ago
Great product
Rebuilt the transom on a Lowes pontoon.
Coosa board was a pleasure to work with.
Highly recommend it.
November 23, 2018
4 months ago
Coosa sandwich
Absolutely love it! Used in place of plywood for a transom on my aluminum boat. Sandwiched it between 2 pieces of 1/8th inch aluminum plate and bolted it in. Stronger and lighter than anything I've ever seen used, easy to work and practically bulletproof when sandwiched!
September 13, 2018
7 months ago
Coosa board, Great product!
The Coosa board is everything that is advertised. It appears to be much lighter in weight, yet as strong as marine plywood. It works easily with cutting tools ands absorbs resin readily.The fact that it will not rot from water or deteriorate is a big plus. I would recommend this product to anyone who wants to do it right the first time!Very satisfied.M. Donathan
September 4, 2018
7 months ago
first look at a new product (for me)
first time I have used it...looks great out of the rigid as I had hoped....will be interesting to see how it 90 degrees together...planning on using 5200....wood angle bracing.... and a few long screws....looks perfect for motor boxes, pilot house wall, etc
August 30, 2018
7 months ago
Coosa, great product.
Replaced the rotten wood in a deck hatch. Two 1” thick Coosa and 4-5 layers of epoxy and woven glass. Lighter and stronger then it came from Ocean Alexander. Easy to use, I’ll use it again.
August 13, 2018
8 months ago
Coolant board
Very light yet strong
June 23, 2018
9 months ago
Transom and stringer
Coosa bluewater 26 is extremely easy to work with, very light and unbelievably strong
Center stringer, three 3/4” pieces of coosa, laminated with 1708.
Fountain Transom
Fountain Transom
December 5, 2017
1 year ago
Questions / Answers
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Browse 60 questions Browse 60 questions and 65 answers
I'm looking to replace the plywood transom on my 10' inflatable boat. Can Coosa board be used as a substitute? If so, what type of adhesive would be best ?
Bill Brousseau on Jul 21, 2017
BEST ANSWER: Coosa board is ideal for transoms, and most high end boat builders have gone to Coosa for the long term durability & weight savings.

It's very easy to work with (although you'll want some gloves and a mask because it does have fiberglass in the sheet). Alternatively, if you wanted to send us a template, we can cut a piece for you to the exact size/shape of your transom.

Regarding adhesives, I've linked directly to Coosa's recommended adhesive list -
Can this be used for a swim platform?
A shopper on Feb 1, 2018
BEST ANSWER: This material can be used for a swim platform, but it is a raw material. You will likely need to fiberglass the board for additional rigidity. If this isn't necessary, you will still need to cover the Coosa to protect users from the fiberglass in the material.
I have a 1994 16' bass tracker and am considering replacing the floor and all other plywood, looking for my best long term option. what info would you need for an estimate?
Artie R on Jul 14, 2018
BEST ANSWER: Great question! Coosa is a great long-term alternative to plywood. Please give us a call to discuss the specifics of your project for a personalized quote.
I'm Replacing the aft center floor deck of my 1981 Ski Natique. The motor cover bolts to the deck via hinges. Is the coosa board going to resist the amount of pressure that could be applied there?
Shane A on May 20, 2018
BEST ANSWER: Great question Shane!
The Coosa Board doesn't quite stand up to standard screws the way wood does, so if you through-bolt the hinges instead of a standard screw you shouldn't have any issues with the Coosa Board.
Can you get the coosa board custom cut to a specific size?
A shopper on Apr 1, 2018
BEST ANSWER: Great Question,

We can most certainly take care of that. You will need to give us a call in order to get this taken care of.

I am replacing an old plywood firewall in my boat would coosa board be a good use for this?
MIkeG on Feb 10, 2018
BEST ANSWER: Great question. Coosa board would most likely be excellent in this application and we would love the opportunity to discuss the specifics with you on this. Please feel free to reach out to us for more information and get started.
can coosa be cut into 2” wide strips and layered to make supports for a coosa deck?
A shopper on Jan 4, 2018
BEST ANSWER: This certainly sounds like something that can be done, but we could not tell you from experience. You will want to make sure to fiberglass all the way around the supports to get the full rigidity you are likely looking for. Thank you!
I’m looking to replace a 1.5 in thick plywood transom on a late 70s Starcraft aluminum boat. Boat is rated to a 140 hp motor but transom is failing with 115 Yamaha 4stroke. Already replaced the transom about 15 years ago, so figuring I need to beef it up a bit. Was considering taking a piece of 1” ply and coating it with fiberglass. The splash tray is screwed to the inside of the transom and definitely adds some structural support. Would coosa board still have enough “screw hold” for this application. I would love to not have to do this project again. Any advice? Thanks.
Nordie on Jan 3, 2018
BEST ANSWER: Hello, Cossa is an excellent material for transom replacements it is typically recommended to us the same construction method and material thickness as what was originally used by the manufacturer. As for screw retention, Coosa does not hold screws, not quite as well as plywood but depending on the project there are some options available. If you would like to discuss your project please feel free to give us a call and we would be happy to talk through your options with you.
Is this being used in floors or aluminum boats in Half inch thickness or is it not rigid enough. Thank you
Brian earley on Jul 22, 2017
BEST ANSWER: Hello Brian, that is a great question. It is always recommended to use the same thickness as the plywood the Coosa would be replacing. If you are adding this floor from scratch the thickness needed would really depend on how it it is supported underneath. If you would like to discuss the specifics of your project please feel free to give us a call and we can go over some options for you.
can you laminate 2 sheets of 3/4 inch coosa board together to make 1 1/2 inch and if so what do you glue it together with i.e fiberglass resin?
Truman A on Feb 28, 2019
BEST ANSWER: You can laminate coosa just like you would laminate wood or plywood. I have laminated 3/4 inch coosa to make a 1 1/ 2inch thikness in a transome. I would use a quality epoxy resin with a small amount of filler in it to glue the boards together.
I have a 1988 Bass Tracker and want to replace the 1" transom with the coosa board and cover it it with aluminum plate on the inside. I was thinking of adhering it with 5200. it has a 60hp motor. Will Coosa board work will for this fix?
Jonathan J on Feb 19, 2019
BEST ANSWER: I'd get thicker than 1" coosa board and then sandwich it between 2 aluminum plates. It's very rigid and waterproof . Then I'd drill and use stainless hardware to mount your 60 hp motor. That should handle the torque of your 60 hp motor and you won't have to worry about wood rot.Be sure to silicone any transom penetration throughly.
Being this is raw, and has a rough surface; can you sand the roughness out to paint or do you recommend a laminate instead; if not used in boat applications?
E M on Feb 12, 2019
BEST ANSWER: The coosa material is porous so even when sanded the tiny holes remain. I used it in place of wood for a transom repair and fiberglassed over it. PVC board or starboard are water and UV resistant and do not require a topcoat.
I have a 1983 bass tracker ll need to replace transom can buy it to fit my boss?
George on Feb 28, 2019
BEST ANSWER: I rebuilt my transom in a 96 aluminum bass boat with coosa board. I bought a 4’x 8’ x 1/2” sheet, used my old transom to trace the outline. I cut three pieces to make it a 1 1/2 “ thick. I went a little overboard and sandwiched 1/8” aluminum in between the three peices of coosa and cut a 1/2” piece of aluminum for the rear of the transom this gave me the same thickness of the transom i was replacing, but much stronger than the plywood that was in there in case i want a bigger engine in the future and it will last longer than the boat.
I am replacing the half inch thick plywood flooring in my motorhome that is screwed down to metal floor joists if I use your coorsa board do I screw it down also and can I glue a laminate flooring to it?
Frederick R on Mar 3, 2019
BEST ANSWER: Hi Frederick,

Great Question! You can use Coosa board just like you would plywood. Screwing it down to the metal floor joists would be no problem. You can use adhesives on the board as well so gluing down laminate floor to should be no problem.
Can Coosa bend on a slightly curved transom ?
Jeffrey M on Feb 18, 2019
BEST ANSWER: I dont see how unless you bought a thick piece and carved out what you needed to make it fit. It's very stiff and will not bend that I can tell.
When will you sell products in a 1x4 or 1x6 ?
Steveo on Feb 17, 2019
BEST ANSWER: Hi Steve, If you contact us on our contact page, we will better be able to answer your questions.
Does it contain any VOCs? I’d like to use this to replace the plywood flooring in my 1971 Airstream. Additionally, I’d also like to build wall partitions for a shower, bunk beds, kitchen, etc. Your thoughts on this and any recommendations for finishes to prevent fiberglass fibers piercing the family would be greatly appreciated.
John M on Jan 31, 2019
BEST ANSWER: I don't know about official VOC numbers, but there was no odor and no indication of any VOCs when I received. The boards are lighter in weight and stiffer than standard plywood. There is no moisture or wetness they are completely dry with no smell. Any kind of paint should work, but you will need several coats as the surface has some texture. Handle with gloves to avoid the fiberglass itch, until you get a primer coat on it then it should be fine. It cut with a circular saw the same as wood does, only a little dust.
I own a 204 grady walkaround. It has a 175hp Johnson on it now. Transom is shot. I want to repower it with (2)100-115hp outboards. What thickness coosa board should I use or should I sandwitch (2) 3/4” pieces together? Thanks
Gator on Jan 25, 2019
BEST ANSWER: if the transom was laminated 3/4 plywood , I would use the same lamination of coosa to replace it. it Is easily as strong as the original plywood but remember that it will not hold screws as well as the plywood.
What is the weight per square foot of 1/2" Coosa Board?
Burton C on Jan 10, 2019
BEST ANSWER: Hi Burton, A full sheet of 1/2" Coosa is 35lbs. That makes each square foot just under a pound each.
I am interested in using the Coosa material to replace plywood as the subfloor in my Airstream trailer (to be covered with a Pergo laminate decorative floor). Can I use the Coosa right out of the box, or does it need to be coated or epoxied first?
Keith S on Dec 28, 2018
BEST ANSWER: Hi Keith, Coosa does not actually need to be fiberglassed, it is not UV resistant, but in an enclosed space it will work well. As for what will stick to it, there are no guarantees. Considering it is a foam and fiberglass mix, it does not have a gloss finish, so there is no telling how those products will stick to it.
can I buy a smaller size of 3/4"...lets say 12" x 24" ,or something like that?
lincoln s on Dec 26, 2018
BEST ANSWER: Hi Lincoln, Great question! Unfortunately, you have to buy the sheet in whole sizes such as the smallest which is 48" x 31.5". We can cut it to whatever size or shape you want for a charge but you have to buy that whole sheet size.
I’m retrofitting the center console on a 1978 Whaler Sport, & want to modify-glass in a forward “coffin box” to the existing console...based on size limitations-dimensions, I estimate 225-250Qt of capacity...Will this product work well for an integrated custom built cooler to replace my SSI or Yeti...?
Wayne S on Dec 24, 2018
BEST ANSWER: Hi Wayne, Great question! Coosa Board is perfect for that. Considering it is a foam core product it will naturally insulate, which is perfect for a cooler box build.
I am using Bluewater 26 to replace my soleboards on my sailboat. The old material is 5/8 plywood with 1/16 veneer. The spans between stringers supporting the boards are max 2ft. I would get best material use from the 5x12 sheets but since they don’t come in 5/8, will 1/2 inch support a 250lbs between 2 ft spans?
Scott on Dec 5, 2018
BEST ANSWER: Hi Scott, That is a great question! Coosa Composites recommends replacing existing panels with exactly the same thickness, just out of Coosa panel instead of plywood. Ideally for you it would be a piece of 5/8 inch Coosa panel which most likely is fiberglassed on both sided for rigidity considering a 24" stringer gap is quite large, but not unheard of.
The problem, which you already understand is that we do not sell 5/8 inch Coosa panel. Your safest route to get more accurate answers to your question on support is to contact Coosa composites directly. You can find them in the link below:

They would be able to better address what your best option is in terms of rigidity and material thickness. We do not want to give you the wrong information! If you have any other questions or concerns please do not hesitate to reach out to us at 866-633-7961. Thank you!
Can the 1/2" Coosa board over a 6ft span be bowed with a 1.5" camber in the middle?
Douglas R on Oct 11, 2018
BEST ANSWER: This really is a great question. Coosa Composites says that the material should not be bent, but we have seen applications where the coosa has been clamped and installed to a very slightly curved surface over a long distance (this can be seen in the Ship Shape transom installation video on our website There would be more stress on the board as a result of the curve, but it is likely possible that you can get the desired curve you are looking for. We cannot say that Thank you Doug!
Can this be used for replacing the decking on a pontoon boat?
Amyashworth on Sep 9, 2018
BEST ANSWER: Great question. Yes, the Coosa board would be perfect for this application. Please feel free to give us a call to discuss your project.
I'm looking to replace the core material on 1976 cj-5 jeep body. Can I assume this product is a good option? There was 1/4" end grain balsa on all the floor surfaces, and an additional 1 1/2" at the body mount areas.
Ryan B on Aug 30, 2018
BEST ANSWER: Hi Ryan, Coosa board is a great option for replacing wood, especially in structural areas. However, I cannot tell you that this is the best option for you cj-5 body. The smallest thickness available is 1/2", but the 1.5" coosa should work well around the body mounts. Thank you!
I want to replace some large wood lazzerette covers on my boat. They double as a standing and seating area. Can I use 1" Coosa coated with fiberglass for this purpose? As the covers are about 4'x2' will I need to add structural ribs on the underside to prevent the Coosa from cracking? I also need a 4 inch face lip can i glue the coosa or screw it together prior to glassing?
Eric J on Aug 14, 2018
BEST ANSWER: Hi Eric, good questions! 1" coosa should work well for this, especially if you are glassing it and adding structural ribs. You might even get away with 3/4" on this. You can certainly glue this material, and Coosa recommends using a two part epoxy from scotch weld, but if you will be glassing the material, you might just glass on your lip as well. For more info on this please reach out to us at 866-633-7961. Thank you!
Dose it come in1/2 “?
William K on Jul 29, 2018
BEST ANSWER: Great Question William,

This product does come in 1/2" thickness. On our website page, you can view the many different thicknesses and size variations by choosing them from the two drop-down menus.

Thanks William!
I'm planning on replacing some floor panels on my bass boat. Is it easy to carpet over Coosa?
WillieBeamin on Jul 10, 2018
BEST ANSWER: Hello Willie, you can definitely carpet over Coosa, I would recommend using an adhesive to hold the new carpet on the Coosa. You can still use any of the same adhesive and installation methods that you would use if you were to replace it with plywood.
I have an aluminum boat and looking to replace the transom. It would be in the pnw and curious if it would with stand the rain.also since it’s aluminum do I need to epoxy it?
Jholly on Jul 4, 2018
BEST ANSWER: Hello Jack, Coosa would be a great material anywhere there was originally plywood. It gives you the same strength and you can use the same construction methods as wood but it will not absorb water or rot It is recommended though that you cover the material in some way to keep it form discoloring. If you would like to discuss the specifics of your application please fee free to give us a call and one of our sales associates would be happy to assist you.
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