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bertsboat
04-15-2010, 02:10 PM
WOOD VS COMPOSIT (FOAM) COOSA COMPOSIT BOARD

I see money and work going into some pretty expensive and impressive restorations and I see something that troubles me. That wood is being used in favor of new and better materials. The reason we have to remove the deck (other than gas tank issues) is that the wood has been compromised and water has entered and deteriorated the core of the hull, stringers and deck.
Seems to me we would not want to make the same mistake and replace the wood with the same problem causing material WOOD.
I am sure if you were looking for a new boat you would look for one that used no WOOD in the production or as little as possible. True, there would be a cost involved but that cost would be small compared to the problems we have seen all too many times in a fiberglass boat.
When buying a boat what is the first question that comes to mind? Of coarse the price but after that the question is how are the stringers and the transom? They MUST be rotten. If they are not then it has just been rebuilt. If rebuilt, who did it and what did he use to do it with.
OK So I say it again, why did you use WOOD AGAIN??????
What is COOSA BOARD?
Coosa board is structural panels made of high density, polyurethane foam manufactured with layers of fiberglass.
The NO-ROT (key word) and light weight (7 pounds less than a comparable size sheet of ply wood) advantages of foam combined
With the structural properties of fiberglass make Coosa panels an excellent replacement material for WOOD and other traditional core materials.
These panels can be ordered in 5X12 ft up to 5X12 ft and can be pre-cut. http://www.coosacomposites.com/ (http://www.coosacomposites.com/)
I would think members here would embrace this product to avoid future traditional failures encountered in the past.
This product along wit the use of 1708 fiberglass cloth makes a forever repair that is WAY stronger than original.
Regards,

glashole
04-15-2010, 03:04 PM
would have to say the additional costs of this product would steer me away from it and stay with the original tried and true wood encapsulated

would,'t want the foam to flex with the strain of a high HP motor

just do a better job of it the second time

call me in 30 years and if i have the same boat i will let you know how it is making out

Shea

bertsboat
04-15-2010, 03:19 PM
The main reason that I ignore most of the posts on these message boards is simple, The average guy on here has already made up his mind, based on the ease and availablity of wood for his transom.

They don't want to even consider a non-wood alternative, for the same reason that they didn't take a Physics elective in High School...They don't want to feel dumb, they don't want to learn how to master a new process (although its relatively simple).

It is the main reason that Ford owners hate your chevy truck, and Camaro owners hate Mustangs. They want to re-assure themselves that they made a WISE buying decision.

There is no intellegant community searching out new product and boat building ideas. Everyone is talking and FEW are LiSTENING.

Just Say N20
04-15-2010, 03:37 PM
Whoa! Slow down there, just a little.

People usually feel more comfortable with what they know. Just human nature.

Coosa board has been discussed here before, and if I remember correctly gcarter was very open-minded regarding the plus/minus of the product.

Seems someone (I'm thinking Silverghost?) bought some instead of wood based on that dialog for a project he was doing, for many of the reasons you mentioned.

I appreciate what you wrote, and that you took the time to do so. Knowledge shared is a good thing.

I don't know what the cost is, but I paid $120 for a 4' x 8' x 3/4" sheet of marine plywood for redoing my stringers. I knew what to expect with wood, and I figured that the non-marine (I don't know this for sure) plywood with raw limber holes in my boat lasted 42 years.

So I figured better wood, WEST epoxy, sealed everything, should last at least another 42 years, at which point I will be 96, and probably won't care. :biggrin:

BUIZILLA
04-15-2010, 03:55 PM
my Sea Hunt fish boat is all Coosa...

light too.. :pimp:

which is a main reason I bought it..

joseph m. hahnl
04-15-2010, 04:30 PM
I believe all the newer Donzi come from the factory with foam stringers.
My understanding is that the wood or foam is only for filler. The stresses are taken out on the fiberglass frame work around it. If this is in fact true. Why would you ever cut it apart just to replace filler? Why not just reinforce it with more mat and resin. I can see it needs to be where the motor mounts are and even that can be done with kiss block standoffs
in between a metal channel or plates.

I do agree that if you go to all that trouble to remove rotted filler to only put more rot able material doesn't make sense.

Funny Though how people act like the foam isn't a provin technology. I think I can safely say it's been used for decades.

I would also like to note that being a lighter material means lighter boat less displacement more speed. so from a performance standpoint it would make more sense to use foam. Hmmm!! I wonder if that's why the Factory went to using it?

I Think the bottom line comes down to performance enthusiast and classic enthusiast
http://images.webkrafters.com/trinity/26000/53stude26032-1.JPGhttp://www.hubcapcafe.com/i/2000/branson/stude5301.JPG

Some people think stock is better:rofl:
http://www.youtube.com/watch?v=AMsjRtOHXow

bertsboat
04-15-2010, 05:24 PM
Thank you sir!

glashole
04-15-2010, 05:28 PM
well

i don't agree with it

come down to AOTH for a complete discussion on the pros and cons

:nilly:

rustnrot
04-15-2010, 05:47 PM
1. While not necessarily something that would be required in a Donzi, can I lag bolt into Coosa?

2. Can you suggest a laminate schedule using Coosa as the core for stringer replacement in a Donzi 16 or 18 Classic?

thanks!

hardcrab
04-15-2010, 05:52 PM
Coosa Bluewater is a lightweight, WATERPROOF . high strength (far superior to plywood) fiberglass stranded board.
It is easily cut and shaped, drilled, glued and screwed.
About $300 for a 3/4 X 4X8 sheet.

It is used for stringers and transoms and anywhere a permenant light weight, super strength and WATERPROOF application is important.

DonziJon
04-15-2010, 06:32 PM
Just a completely different thought ..just to muddy the water. I'll get to the point in a minute.

I worked for Brown & Sharpe Machine Tools back in the seventies. For a Century, floor standing machine tool bases for (Lathes, Milling machines, Automatic Screw machines, grinders,..etc) had been cast iron..made in a foundry.

In the seventies, "Foundrys" were coming under fire for environmental reasons. So we decided to try "Fabricating" machine bases out of sheet steel....welded. It didn't work as we had hoped. When the machine was fully assembled and running...the fabricated steel bases caused the machines to RING..... Transmit machine sound to the environment like never before. Cast iron on the other hand had the abbility to "Dampen" sound.

So I wonder if composite cores in engine beds (solid and completly rigid) would cause such ringing through the hull in a Donzi Classic. :nilly:

mattyboy
04-15-2010, 06:33 PM
Can any examples be given for go fast boats with all composite construction? Also can any examples be given of durability and longevity with composite under our type of boating?

I may not be the sharpest but arguements have been made that newer donzi have composites in them would these be the same donzi that have been cracking under higher hp applications? of course one would be foolish to not see layup and workmanship have much to do with longevity regardless of materials used. Not to mention care and upkeep .

I guess my point my 67 16 is still going strong some 43 years after being leaving E188th st with wood construction. I guess time will tell with these newer technologies. again I figure like Bill if it went 40 + the first time done without sealing if it is done right should last at least that long done properly.

I guess Bert you'll have to run that 14 hard for 10 years or so and then let us know how it holds up.

gcarter
04-15-2010, 06:39 PM
Yes, we've had EXTENSIVE discussions on Coosa.
If you do some serious study into how to build boats and to accomodate high clamping forces on foam cored stringers, and transoms for that matter, the approved manner is to cut out fairly large areas in the core where the bolts will be and fill the cutouts w/epoxy or similar material to standup to the high forces.
I've now done several of these boats, and have yet to run into any rot. If I do more of them, I know I will, but so far, It's not been an issue.
It's easier to use wood for those challenged ares, like the engine mount areas, and the gimbal assembly, you needn't worry about really torqueing down the bolts.
I really like Coosa as a core material, but I wouldn't necessarily use it everywhere.

bertsboat
04-15-2010, 06:42 PM
Uimate high strengh to weight ratio. I spent $400 on Bluewater 26 to do the 14 Baby. I could have saved $200 if I had used wood. I will rest in peace knowing my Nephew Billy will never see the side of this boat I did.
Just boating and more boating.

mike o
04-15-2010, 07:00 PM
High density foam has been around for 25 yrs like Airex. Airex is a vacuum bag only material type foam. Anything layed up under vacuum can be completely totally sealed with only (2) 6 Oz layers of cloth. Stiff and light weight is the advantage of any foam. But, If any of it (any foam) gets wet and freezes it will turn to powder and a sandwich panel like coosa "might" fall apart faster than wood "possiably" with the same amount of moisture intruded. Its all about keeping everything dry. Thats y they telling and showing to cover it with that super dense 1708 fabric. Unlike that old school 28 or 32 oz roving you see in the pictures being cover up. It let all the moisture-water in the laminate because the weave is wide open. Repairing small sections wont save ya much in the over all weight of an old over built boat for the cost. Thats because everything was over build in the old days. If your ripping and tearing the whole boat apart like some do here. Its probably worth it, if you know what your doing. Saving a lot of weight will pay off in the long run on fuel..........:kingme:

mattyboy
04-15-2010, 07:47 PM
Mike
great info so it is just as vunerable to water as wood in a climate where it freezes, so you'd have to do some kind of sealing around cuts and bolts just like wood or you could suffer the same as wood.

realbold
04-15-2010, 08:01 PM
I redid engine beds with high density foam and would have tried Coosa if it was around then, or maybe it was and I didn't know of it. But there is nothing wrong with using wood as long as its sealed properly. I would do it no different with Coosa. The reason the original wood rots is always due to poor workmanship.

Walt. H.
04-16-2010, 12:23 AM
The main reason that I ignore most of the posts on these message boards is simple, The average guy on here has already made up his mind, based on the ease and availablity of wood for his transom.

They don't want to even consider a non-wood alternative, for the same reason that they didn't take a Physics elective in High School...They don't want to feel dumb, they don't want to learn how to master a new process (although its relatively simple).

It is the main reason that Ford owners hate your chevy truck, and Camaro owners hate Mustangs. They want to re-assure themselves that they made a WISE buying decision.

There is no intellegant community searching out new product and boat building ideas. Everyone is talking and FEW are LiSTENING.
Hey Bert,
From your above post sorry to say you sound very arrogant and opinionated coming off like you're cruising for an argument standing on a soapbox with your insulting demeanor about others right from the get go, i'd suggest cutting back on the caffeine or what ever else got you wound up so you don't find yourself being ignored by those you stated you've been ignoring.
And one more observation as you commented to Shea aka Glashole, one could also say the same exact thing about your avatar that it says it all too but then that would be insulting as well.
Anyway the content of your topic is good, its just your delivery needs alittle diplomacy.:wink:

mattyboy
04-16-2010, 07:35 AM
well it looks like the composites have their cons as well and it boils down to what works best for you and your boating environment.

I do get a kick out of the comments "we talk but don't listen " coming from a guy who has jumped in on a tire thread and how to remove a transom housing thread ranting about using wood in a restoration. sounds like someone is shouting to get noticed??


again the question remains

what go fast mfg'rs are using composite stringers and transoms, for how long and how are they holding up?

I may not have taken a physics elective but from limited dumbness I know if you want to make a point, you need facts and that kinda stuff to back it up.


Mike again thanks for the info, maybe George could link the thread about the composites.

got to go I have bad news for Pearson, the pumpkin is 10 years old now and well it is going to fall apart on him

oh and a last point to mull over, taking weight out might help speed and fuel economy but it will also effect ride wiil it not?? too much weight taken out and you'll start bouncing off waves not cutting thru them.
less weight will also effect feel and sound too will it not??

tawk amognst yourselves


funny as I sit here on the 18th floor of 230 west 38th st and look out over the roofs of the bdlgs in NY city , every bldg has a water storage tank on it, guess what they're made of???? WOOD seems to me if newer technology was around and better they would be made of something else but WOOD LMAO :p

glashole
04-16-2010, 07:44 AM
i just started this to give bert a hard time, wasn't really thinking it would be a huge discussion but obviously there are solid arguements for both sides

but as Matty was asking are there any proven results on using the composite construction?
can it be screwed into enough to hold say a set of k-plane pumps, or even a set of k planes hanging off the back?

proven results bring along respect

on another note

was helping a buddy fix up a steeple that was made of wood and had a copper covering

we were rebending all of the copper and fitting it to the thing building it exacly as it had been done 40+ years ago only we were using pressure treated lumber underneath

we started talking and I asked why they were building it the same as before if it rotted and had to be redone and why not make one out of stainless

the answer was " so it will be like it was originally"
The I asked " well if they had the technology to make it out of stainless originally they probably would have"

gcarter
04-16-2010, 08:03 AM
The weight discussion is interesting and reminds me of the wannabe Lance Armstrong bicycle racer. He spends $5K-$10K on the ultimate bicycle that is lighter and stronger than anything made before.
But the truth is, the guy is 75# overweight and the huge investment is completely meaningless.
There was a very interesting thread on another site about high tech race boat hulls. The interesting thing was it was between actual people in the industry. One of the details that came out was today a 38'-40' raceboat hull could be built that weighed only about 3,500#.
But all that is almost meaningless as the boats need water ballast tanks in the bow, the extra weight savings is carried in fuel and other consumables. At the end of the day, the boats really weigh the same and the real benifit is the newer materials are stronger........and the boats not necessarily lighter.

MOP
04-16-2010, 08:45 AM
Like mentioned above the real strength is in the laminate not the wood or coring materials, the majority of rot that I have seen is from what I will kindly call manufacturing error you call it what you like! Transom/stringer rot is caused by water weeping in from two places the stringer bungs and the hull drains not being sealed properly! The biggest thing that has always bothered me is VERY few manufacturers isolate the stringer wood from the transom wood! By not isolating one will leach into the other! Most every I/O transom that I did over was in fine from about 1/2 way up bone dry, just the bottom was shot and so were the several feet of the stringers. When doing one over the transom should be fully completed first the the stringers fitted slight loose removed and fully encapsulated, bungs bored and glassed then glassed into the hull. Where there is any possibility of water intrusion wood should never come in contact with other wood. Even the wood I used in the 22 which was aged and treated and was fully encapsulated, true it will never rot but any end grain exposed to water will leach and the wood get vary heavy over time.

berstboat why are you shouting at us! A full caps post is considered shouting we can all read regular type!

gcarter
04-16-2010, 09:01 AM
Here's the thread I reffered to about one of the discussions on Coosa.
http://www.donzi.net/forums/showthread.php?t=58236&highlight=coosa

Please note my comments about using several layers of 1/2" Coosa for stringers, rather than one, to help compensate for crushing from clamping forces.

It's one thing to mount a 3.0 Merc or a 4.3 V-6 to some stringers,
And then there's 500 HP and 500 '/# of torque on essentially the same stringers.
On this site, we've seen a lot of damage from such installations.

rustnrot
04-16-2010, 09:06 AM
The weight discussion is interesting and reminds me of the wannabe Lance Armstrong bicycle racer. He spends $5K-$10K on the ultimate bicycle that is lighter and stronger than anything made before.
But the truth is, the guy is 75# overweight and the huge investment is completely meaningless.
There was a very interesting thread on another site about high tech race boat hulls. The interesting thing was it was between actual people in the industry. One of the details that came out was today a 38'-40' raceboat hull could be built that weighed only about 3,500#.
But all that is almost meaningless as the boats need water ballast tanks in the bow, the extra weight savings is carried in fuel and other consumables. At the end of the day, the boats really weigh the same and the real benifit is the newer materials are stronger........and the boats not necessarily lighter.

Well said. Regardless of the core, the laminate schedule will probably be identical (my question never answered). So let's assume two 4 by 8 sheets of Coosa vs. plywood are used in a restoration. Based on the data here, that's only 14 lbs. The difference is virtually unmeasurable or observable.

mattyboy
04-16-2010, 09:14 AM
The weight discussion is interesting and reminds me of the wannabe Lance Armstrong bicycle racer. He spends $5K-$10K on the ultimate bicycle that is lighter and stronger than anything made before.
But the truth is, the guy is 75# overweight and the huge investment is completely meaningless.
There was a very interesting thread on another site about high tech race boat hulls. The interesting thing was it was between actual people in the industry. One of the details that came out was today a 38'-40' raceboat hull could be built that weighed only about 3,500#.
But all that is almost meaningless as the boats need water ballast tanks in the bow, the extra weight savings is carried in fuel and other consumables. At the end of the day, the boats really weigh the same and the real benifit is the newer materials are stronger........and the boats not necessarily lighter.

George, so what you are saying is if you use composite in a donzi you would need to add weight to maintain ride and if you use plywood you don't

so in other words

Skinny Chicks = WOOD
Fat Chicks = NO WOOD

:p

CHACHI
04-16-2010, 09:35 AM
Well said. Regardless of the core, the laminate schedule will probably be identical (my question never answered). So let's assume two 4 by 8 sheets of Coosa vs. plywood are used in a restoration. Based on the data here, that's only 14 lbs. The difference is virtually unmeasurable or observable.

From the weight side of the equation. What is the difference in cost?

Why would (no pun intended) a builder like Donzi use a non-wood product
that cost more in an already overpriced boat? From Donzi's side, hey wood has worked so well for so long ......

I am sure that a stock build will get the owner/owners 10-15 years of ownership with little to no problems given the boat has some care and protection from the elements.

I am sure Donzi or any other boat company could care less if an owner 20 years out has to change stringers/transom.

Some boat companies are using wood free construction and I applaud them. I consider it forward thinking.

Someday there will probably be a big injected molded piece that just drops in to a hull and just gets bonded down. Wait doesn't Formula do this to some degree?

Just rambling....

Ken

Just Say N20
04-16-2010, 11:08 AM
Skinny Chicks = WOOD
Fat Chicks = NO WOOD

:p

Very, very clever. :biggrin:

mike o
04-16-2010, 11:55 AM
Mike
great info so it is just as venerable to water as wood in a climate where it freezes, so you'd have to do some kind of sealing around cuts and bolts just like wood or you could suffer the same as wood.I'm just talking shop. So take it for whats its worth I'm not putting any material down. Coosa is a sandwich of foam and glass panels, so you have different density materials in that panels. the foam provides light weigh stiffness. If the foam get wet it will be much heavier than wood would be wet, cause foam is like a sponge. And I would think that the foam- glass panel would delaminate from long term pounding. Because the structural part of the foam "could" get compromised and the panel fall apart. Old 13 Boston whalers from the 60 where full of foam and weighed 800-900 lbs. Ever try to pick up a old water saturated 13 whaler? It takes 4 guys busting nut:kingme:. They weigh a ton, full of water. Some high end ski boat companies when with ALU stingers long ago. When you use all the high etc stuff, you have to build the whole boat with all the other high etc stuff, resins, fabrics etc. In other words you don't spend the $ on Kevlar and wet it out with a cheap resin, your wasting money. Every building material has there own proprieties ans really wood has the most for the $ like compressive strength in a transom. So whats best, Ill take the light weight boat, full of skinny girls, with an over weight full cooler.:kingme::kingme::kingme:

VetteLT193
04-16-2010, 12:08 PM
using a new, high-tech, material for one part of an old boat is like putting a Carbon fiber hood on a Honda Civic and thinking you are Billy Bad Ass.

Are there other options to wood? Yes. Does it make sense to use in random boat repairs... maybe. But probably not on 30+ year old boats.

The idea behind a classic is to have fun on the water not be the absolute latest and greatest. And this is coming from one that will update with the resto-rod thing going.

MOP
04-16-2010, 03:01 PM
Another point that needs to be brought up, laminating to composites especially foam is not as easy as it sounds. I did quite a bit of foam and honey comb work it takes a little more know how than some think, if you intend to use these product "DO YOUR HOMEWORK"!

The way to support cored laminates in sections where they must have clamping pressure and stress is to solid glass core plugs. I used to make thick plugs in a cake pan using roven woven, I would and lay pieces cut to fit the pan to the build up I needed for the particular job then lay plastic over it and set a 40lbs block of lead on top to compress and force out excess resin.

Excess resin is a killer in many jobs!!! I have seen so many jobs glisten with resin, just looking at work like that tells me it will break twice as fast as a proper layup, more then needed is not GOOD!

gcarter
04-16-2010, 03:06 PM
I subscribe to Professional Boat Builder, and ,no surprise, more and more mfgr's are using high tech materials in their layup schedule. It only makes sense to do so. The more these materils are used, the more the price comes down, the more the necessary processes are in the forefront. I think, but don't know for sure, that the material cost difference of using
things like vinylester resins, by-directional stitchmats, infusion processes, completely waterproof core materials may be only 20%-30% more than the materials and processes of 30 years ago. A big part of the difference today is the processes that require more specialized talents and tooling.
A company needs to decide that's the direction they want to go, and buy the tooling, and train their staff. They can't look back. They probably can no longer just hire bodies off the street to do this kind of work.
I really don't know were Donzi is in this transition.

joseph m. hahnl
04-16-2010, 05:03 PM
I don't think that the ballast is added to make the boat heavier, but to balance the boat. Buy using water tanks for ballast you can adjust
the balance for drive-ability and water conditions.

I guess you could call it an attitude adjustment :kingme:



http://www.donzi.net/forums/showthread.php?t=55831&highlight=balance+boat

mattyboy
04-17-2010, 09:41 AM
so let me see if i got this right?


to do a transom with composite you cut 3 boards to get the required shape & thickness then get them into a vacum bag with some resin get all the air out once you have the boards laminated together and cured. then you glass them over then glass them in??. now you cut the holes then reseal the exposed boards. do these boards wick up resin? or are they just encapsulated? can normal adhesive sealers be used or are there special ones?

again the question remains is a go fast mfg'r using them in stringers and transoms?? what does cig or OL use?? and if so how are they holding up?

I appreciate the race boat application but those are really disposeble boats not meant to go fast for long periods time like 10 or 15 years plus cosmetics are not that important either as stress cracks and small areas of de lam that don't effect structural integrity don't matter either.
pull a classic up to a dock with more cracks in it than joan rivers face and see the reactions, remember looks are an important part of the classic thing.

Sweet Cheekz
04-17-2010, 03:43 PM
Hey I think Joan got all those fixed when she replaced her face.
Parnell