# 1989 14ft Rivercraft rebuild



## Goldmine (Aug 29, 2017)

I got the sides cut out and some more sanding done. Is 1/2 Coosa Blue water 20 overkill for stringers and transom? What if l use 3/8 and laminate it for the transom? I've been side lined a little due to knee surgery last week.


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## yobata (Jul 14, 2015)

Cool skiff. I don't quite understand what you're asking about in regards to replacing foam, are you saying it's on the sides? Is it floatation foam?


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## Goldmine (Aug 29, 2017)

Yes the foam is in the sides of the boat. It is for floatation. It is a weird foam. Water does bead up off it. It's almost like the stuff florist use. It's very brittle. Most likely due to age. Once you compress it, it just about disintegrates.


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## yobata (Jul 14, 2015)

I think you made a good decision to get rid of that foam. You could always put some in the bow or in the bottom of the boat?? You can either use 2 part 2pound expanding floatation foam, or get the solid version and cut and fit in spaces


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## Goldmine (Aug 29, 2017)

Got some more work done on the boat. I learned I was to meticulous on the stringer demo. Made templates as I took the transom and stringers out. Then realized I would be able to adjust height in keel with epoxy putty when I put it back together. Rookie mistake=have never worked with fiberglass before.


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## permitchaser (Aug 26, 2013)

So how's your knee. Guess you hopped around on one leg to work on it


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## Goldmine (Aug 29, 2017)

permitchaser said:


> So how's your knee. Guess you hopped around on one leg to work on it


Thanks for asking. Definitely getting better. Physical therapy is getting in the way of fishing/ boat building.


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## Goldmine (Aug 29, 2017)

Finally got both layers of transom ground out. It was a pain once the second later dried out. Did some more grinding on the floor too. I had no idea how much work it would take to get the CSM and woven smooth before I can lay new 1708 down.


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## sbcorley (Jun 13, 2018)

Looks like the same hull design I’m about to redo. I was going to leave the foam in but found a spot that water had saturated. I’ll be tearing it all out and starting from scratch as well. Any updates on this boat?


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## Guest (Jun 24, 2018)

Goldmine, check out corelite fore transom and stringers. I have been having good results with it for thing that will have a clamping load on them like transoms. This stuff will hold a screw too and is cheaper than coosa.It would be overkill for decks and such which I use divinycell, corecell, or nida core for depending on application. The corelite will set you back about $130 for a 4x8 sheet of 3/4”


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## yobata (Jul 14, 2015)

I wanted to post the following link because 1. It is also a Rivercraft rebuild 2. It is the thread that inspired me to rebuild my own boat and 3. @LWalker does great work! I think you may find it useful!

https://www.microskiff.com/threads/14-rivercraft-rebuild-into-flats-skiff.17276/


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## Goldmine (Aug 29, 2017)

Almost got all the demo done. My wife is not happy with all the fiberglass dust on her new SUV. Is one layer of 1708 biaxial going to be strong enough on the hull interior. How much weight and thickness is it approximately with resin? The center stringer and two ribs will be bonded in as well with 1708 6" tape. Going to have a 1/2 inch Coosa board false floor laminated too. All decks and bulkheads will be 1/2” Coosa. The transom will be two layers of 3/4” bonded Coosa. Do I need to grind out the old CSM on the transom before bonding in new core. I've been told epoxy is the best choice. I've ground out the old woven and CSM. It's very thin now, accidentally grinded through the strakes in 3 places. Is it overkill/heavier to use 1708 for all my laminating. I plan on getting a roll of 50" wide to use. My goal is for it to be light and never rot again, hence all the Coosa board. Power will be a 2004 2 stroke Mercury w/ tiller. Thanks! Any recommendations are welcome.


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## trekker (Sep 19, 2015)

Boatbrains said:


> Goldmine, check out corelite fore transom and stringers. I have been having good results with it for thing that will have a clamping load on them like transoms. This stuff will hold a screw too and is cheaper than coosa.It would be overkill for decks and such which I use divinycell, corecell, or nida core for depending on application. The corelite will set you back about $130 for a 4x8 sheet of 3/4”


Where are you finding the corelite? Looks like a pretty good product.


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## Guest (Aug 22, 2018)

trekker said:


> Where are you finding the corelite? Looks like a pretty good product.


I buy it from fiberglass discount store in tampa. It’s a different brand but same product really. As far as the store goes, small business and great guy to deal with.


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## Guest (Aug 22, 2018)

Guys, I apologize! The product I use is a Kommerling CMG blown pvc board called komacell. It’s not a foam board and wasn’t really intended to be used like I do. I was turned on to it by another fiberglass tech and havn’t looked back! The stuff I buy is ran through a belt sander at the factory to achieve bond/shear strength. An acetone bath followed by a wipe with styrene and the bond/shear strength is as good or better than the foam cores that are available. This is heavier than divinycell, corecell, ect... so don’t think it is good for floors and decks. But it is great for stringers and transoms! Also good to core areas that need screw retention or through bolted. A 4x8 sheet runs around $150 too!


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## Goldmine (Aug 29, 2017)

Finally got around to laying some glass. Was experimenting to get familiar with laminating. The 1708 biaxial seemed to not want to lay in the strakes without pulling it up from the other strakes. My buddy was helping me who has built a stitch and glue boat and lots of repairs. We tried laying down csm first then the 1708. Even with the csm he suggested we mix thickend epoxy over the wet out hull so it would stick better. We we're using marine epoxy from boatbuilder with slow hardener. It was only about 72 degrees and I don't think we wet it out enough first. 6oz neat epoxy then 6oz thickend epoxy for a piece of glass 4" x 16". He was telling me you don't want too much resin because it will float the glass and be weaker. I pulled the 1708 up once the resin was tacky and it seemed to adhere fine. Any suggestions?


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## yobata (Jul 14, 2015)

Goldmine said:


> Finally got around to laying some glass. Was experimenting to get familiar with laminating. The 1708 biaxial seemed to not want to lay in the strakes without pulling it up from the other strakes. My buddy was helping me who has built a stitch and glue boat and lots of repairs. We tried laying down csm first then the 1708. Even with the csm he suggested we mix thickend epoxy over the wet out hull so it would stick better. We we're using marine epoxy from boatbuilder with slow hardener. It was only about 72 degrees and I don't think we wet it out enough first. 6oz neat epoxy then 6oz thickend epoxy for a piece of glass 4" x 16". He was telling me you don't want too much resin because it will float the glass and be weaker. I pulled the 1708 up once the resin was tacky and it seemed to adhere fine. Any suggestions?


If you are using epoxy, there is no need for CSM, that includes on your biax... instead of using 1708, try just a 17oz biax (or even a 12oz biax).

CSM requires the styrene from polyester resin to dissolve and help it lay down easier...


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## Goldmine (Aug 29, 2017)

Is this transom template good or should it match the lappy sides and be a tight fit? Also should the transom have tabs that fill the grooves of the strakes? The original build had all those voids just filled with resin.


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## yobata (Jul 14, 2015)

Go for it. Thickened resin can fill those gaps


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## Guest (Mar 30, 2019)

Yobata got it! Just mix up some thickened resin to fill the gaps with, the thickened resin will become core once glassed in.


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## Goldmine (Aug 29, 2017)

Thanks for the advice. Would it be beneficial to glass this in as a whole sheet or cut into 3ft strips overlapping a little on each one? I will trim it to fit better. Each overlap will create a small seam correct?


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## Flatbroke426 (May 5, 2018)

Goldmine said:


> Thanks for the advice. Would it be beneficial to glass this in as a whole sheet or cut into 3ft strips overlapping a little on each one? I will trim it to fit better. Each overlap will create a small seam correct?
> View attachment 67278


One piece is always better


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## Goldmine (Aug 29, 2017)

Well not stoked with my first fiberglass job. It is what it is though. Believe it or not it looks better than the chopper gun job I ground out. Lesson learned my buddy doesn't know as much as I thought. Maybe that's why he had that cheese eating grin on his face. I still want to fill in the patch in the





















picture. Still has a little bevel in the middle, problem is the resin has cured. Any advice?


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## Guest (Apr 1, 2019)

This will need ground back out unfortunately. The glass is just too dry and/ohas a lot of air under it. Grind it out, cut a patch piece to overlap the rest by 2-3” and glass it in. Make sure to bevel the edge so when you lay in the patch it doesn’t create a big hump.


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## Goldmine (Aug 29, 2017)

I'm afraid a lot of the glass I put down today is too dry. Expensive mistake. Resin calculator says a beginner should use 1.2g for 17oz. cloth 12ft x 45in wide. This is what's left from a 1.5g kit minus the 14oz we used last month when trying to figure out how the glass would lay in the strakes. It was a pain. We skimmed the hull first today with lightly thickend epoxy(syrup consistently.) Let that tacky up then layed the 1708. My buddy wasn't much help. Didn't get it down without air pockets. My help said we'll just cover it with thickend epoxy so we can't see them and cut them open with a razor knife. I was trying to learn/ not let my OCD make it hard. I went behind him scraping out the wood flour concoction that was just glopped in the strakes. Nothing was smooth. That "C" in the middle was where a mixing cup was left turned upside down to let the resin pour out.


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## Guest (Apr 1, 2019)

A gallon of resin will typically wet out around 32sq ft of 1708 with a little left over.
If you are using 1708 and not 1700 you should wet out the hull good then lay your glass into the wet resin. This will soak into the csm 1708 is stiched amd works fine with epoxy as the cam doesn’t have the binders in it that straight csm has. And I hate to say it but... you are right that most of that glass looks too dry and should be ground out. All is not lost, consider it an expensive lesson that won’t need repeating. Get slow hardener for your epoxy and work in the shade or evening under a tarp to keep the dew off while it cures.


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## DuckNut (Apr 3, 2009)

stop worrying about filling the strakes. It is not necessary.


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## Goldmine (Aug 29, 2017)

View attachment 67676


DuckNut said:


> stop worrying about filling the strakes. It is not necessary.


I'm not worried about filling the strakes. They do need a layer of glass on them though. Thickend epoxy was put down to cover up air pockets in the glass. I learned from our mistakes. My Coosa board for the transom was cut darn near too short on the first layer. I will need to fill that gap with putty. If I smooth out the bottom so it contacts the hull all the way across it will not reach the top of the outside skin. I'm sure I can build that up a bit. It's only off by maybe 3/8" at the most.


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## DuckNut (Apr 3, 2009)

Put some thickened resin at the bottom and split the difference. Then build the top to be flush and straight.

You're doing a great job.


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## Goldmine (Aug 29, 2017)

So today I start demo 2.0. When I scrape the resin the cloth is white as new and dry/flakey. If it truly was wet out will it be discolored/ tinted? Suggestions welcome. Total newbie here with OCD.


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## yobata (Jul 14, 2015)

Goldmine said:


> So today I start demo 2.0. When I scrape the resin the cloth is white as new and dry/flakey. If it truly was wet out will it be discolored/ tinted? Suggestions welcome. Total newbie here with OCD.
> View attachment 68112


I don't have an answer to your question, but here is a photo of an area that I used too little resin. I ended up just sanding that part off and re-glassing it...


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## Tonyskiff (Jan 7, 2018)

Goldmine said:


> So today I start demo 2.0. When I scrape the resin the cloth is white as new and dry/flakey. If it truly was wet out will it be discolored/ tinted? Suggestions welcome. Total newbie here with OCD.
> View attachment 68112


Hey mate. Project looking nice. I would grind anything off just take small drill bid make few holes and use syringe to inject liquid resin it will be all good. I did it on mine boat goes 41mph to problems.


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## Goldmine (Aug 29, 2017)

I cut my templates out onto osb to dry fit them before making cuts into Coosa sheets. This is how the boat was originally built. The center stringer will be 3/4. Wouldit be better to orient the outside stringers vertical in the outer strakes.? The way they lay flat over the chines allows a nice contact surface for the sole to bond to. Not sure how much rigidity they offer layed flat though. They will be glassed in so basically are a form for a fiberglass stringer. Opinions welcome. The original sole was not glassed on the bottom. Probably why it rotted. Does the 1/2" Coosa sheet need to be glassed on both sides or just neat coated with epoxy on the bottom. I've got 1708 or this mystery glass.


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