# Question about coring for you have that have completely redone a small skiff



## Wasy_ (Jun 30, 2018)

Hey guys, Learning all i can about redoing an old boat. I have a question about pour foam and coring. From my understanding there are 2 ways to do it.
1. Only core the Freeboard section of the boat. Then pour foam between the stringers. Level foam, Glass over foam. Install Deck.

2.Core bottom and sides of boat. and instal deck on top of the stringers. and have essentially a hollow hull.

All the searches I have seen do not really address this. I know the downside to foam is that it will absorb water if exposed. But aren't all new boats filled with foam? 

If it helps I am building what i believe to be a Wenzel 14 and i have a thread in the bragging spot about it. Just thought i would post here to get the question answered. 

Right now with the way the hull is setup, its straight glass. no core except for the transom. and does not drain for shit. If you catch a bad wave and catch a decent amount of water this thing is going down. So id like to raise the floor to be self bailing, and possibly even install a bilge for extra punch god forbid i take a nasty wave. Along with adding coring for rigidity. ( i wouldn't be out if conditions were not safe for the boat, but safety is a priority as this boat may become what my nephews learn boating basics in.)

Thank you for your input! 
and here! I drew reference pictures while at work lol


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## yobata (Jul 14, 2015)

If you are going to use 2 part expanding foam, just make absolutely sure that area is completely water tight (encapsulated) and use epoxy resin which is more impervious to water intrusion than polyester resin. 

Also, you stringers look huge! For a small boat like this, you could do two smaller stringers...


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## Wasy_ (Jun 30, 2018)

yobata said:


> If you are going to use 2 part expanding foam, just make absolutely sure that area is completely water tight (encapsulated) and use epoxy resin which is more impervious to water intrusion than polyester resin.
> 
> Also, you stringers look huge! For a small boat like this, you could do two smaller stringers...


Yea they are huge. Lol nothing's to scale. I beleive what I see most guys useing for stringers is either 3/4 inch or 1 inch for the stringers?

So you are telling me if I use pour foam I do not have to core the bottom of the hull?


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## BassFlats (Nov 26, 2018)

Why do you feel you need to core the sides.


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## Wasy_ (Jun 30, 2018)

BassFlats said:


> Why do you feel you need to core the sides.


Simply because that's what i see other guys doing. And the added rigidity to the hull i guess? 
I am really new to this. so if anyone knows a better/ simpler/ more productive way of doing this i am all ears! 
Thanks guys


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## yobata (Jul 14, 2015)

Wasy_ said:


> Simply because that's what i see other guys doing. And the added rigidity to the hull i guess?
> I am really new to this. so if anyone knows a better/ simpler/ more productive way of doing this i am all ears!
> Thanks guys


if you add bulkheads, rod holders and gunnels, you will also make the sides more rigid


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## yobata (Jul 14, 2015)

Wasy_ said:


> So you are telling me if I use pour foam I do not have to core the bottom of the hull?


I am not really saying either because I don't know your boat's condition. You could (as I did), add a layer of fiberglass to the entire bottom of the boat (I used 12oz biax). This could be enough to stiffen up the bottom (I am also assuming that your boat originally came with bench seats which also add rigidity to the bottom and sides). On my re-build, that single layer of 12oz biax was not enough and under power, the bottom of the boat would flex. I then added 2 stringers (1x2 southern yellow pine in my case) and ribs to support a "sole" / cockpit deck. I chose to add foam in all the spaces/cavities in between the stringers and ribs before adding a "sole"/ cockpit deck. But all of this depends on the condition of your boat. You absolutely CAN core the entire thing, but sometimes in smaller skiffs like this, it isn't worth the effort/cost.

See the link in my signature for pictures of stuff I describe above.


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## BassFlats (Nov 26, 2018)

You are probably going to have a front deck and some sort of seat tying the sides in. You will be surprised ,when you fasten the floor to the sides, how ridgid the sides get. Wait till then before deciding whether you need to stiffen up the sides.


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## Wasy_ (Jun 30, 2018)

yobata said:


> I am not really saying either because I don't know your boat's condition. You could (as I did), add a layer of fiberglass to the entire bottom of the boat (I used 12oz biax). This could be enough to stiffen up the bottom (I am also assuming that your boat originally came with bench seats which also add rigidity to the bottom and sides). On my re-build, that single layer of 12oz biax was not enough and under power, the bottom of the boat would flex. I then added 2 stringers (1x2 southern yellow pine in my case) and ribs to support a "sole" / cockpit deck. I chose to add foam in all the spaces/cavities in between the stringers and ribs before adding a "sole"/ cockpit deck. But all of this depends on the condition of your boat. You absolutely CAN core the entire thing, but sometimes in smaller skiffs like this, it isn't worth the effort/cost.
> 
> See the link in my signature for pictures of stuff I describe above.


Saved your build thread. Thank you. A ton of similarities with my hull. Yes, the weight concern of coreing the entire hull concerned me especially since i am going with marine plywood on this. for 2 reasons. 1. I dont feel like spending a ton of money for my first build. 2. Up where i live i cant seem to find a composite supplier locally.


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## Wasy_ (Jun 30, 2018)

BassFlats said:


> You are probably going to have a front deck and some sort of seat tying the sides in. You will be surprised ,when you fasten the floor to the sides, how ridgid the sides get. Wait till then before deciding whether you need to stiffen up the sides.


Thank you. This is why im asking these types of questions here. i did not think those would stiffen it up enough. But with transom is redone, 2 bulkheads added, and stringers. It would probably hold up fine. and at tat point i find out its not i could always glass in some coring to the sides correct.


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## BassFlats (Nov 26, 2018)

Here's a couple of pics of a bassboat hull I converted to a tiller flats skiff. No foam below the floor.
View attachment 107370


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## Wasy_ (Jun 30, 2018)

BassFlats said:


> Here's a couple of pics of a bassboat hull I converted to a tiller flats skiff. No foam below the floor.
> View attachment 107370
> View attachment 107372


Thank you. Did you finish it yet? Or just start it?


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## BassFlats (Nov 26, 2018)

I finished it last year.


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## DuckNut (Apr 3, 2009)

@yobata gave you good advice and so did @BassFlats .

You have two issues here which need addressing. 1) stiffness and 2) flotation. If you want it stiffer a layer of 1708 will be plenty on the gunnels. You can add core but not needed.

You need to find places to stuff some flotation foam. If I am right it was under the seats in the original. So, now where can you hide it. Build a walking tunnel like bass did and put it under there. Doing that you will stiffen the sides without anything additional. If not you will need to put it under the floor.


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## PG350 (Jan 19, 2012)

Did you cut out the seats and deck yet? If not dont cut them all the way out, just cut them down to the level of your floor and use the as partial stringers. This will save material and keep the shape of the boat.


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## Wasy_ (Jun 30, 2018)

DuckNut said:


> @yobata gave you good advice and so did @BassFlats .
> 
> You have two issues here which need addressing. 1) stiffness and 2) flotation. If you want it stiffer a layer of 1708 will be plenty on the gunnels. You can add core but not needed.
> 
> You need to find places to stuff some flotation foam. If I am right it was under the seats in the original. So, now where can you hide it. Build a walking tunnel like bass did and put it under there. Doing that you will stiffen the sides without anything additional. If not you will need to put it under the floor.


 I'd like to install a deck and foam underneath that.


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## Wasy_ (Jun 30, 2018)

PG350 said:


> Did you cut out the seats and deck yet? If not dont cut them all the way out, just cut them down to the level of your floor and use the as partial stringers. This will save material and keep the shape of the boat.


You are 100% correct. I have not started cutting anything out yet. I will definitely be doing this.


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## DuckNut (Apr 3, 2009)

BassFlats said:


> I finished it last year.
> View attachment 107392


I just noticed.

That is a first for me. This is the first time I ever saw a house painted to match a boat.


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## DuckNut (Apr 3, 2009)

Wasy_ said:


> I'd like to install a deck and foam underneath that.


Go read the other thread about foam and you will know what to do from it.


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## BassFlats (Nov 26, 2018)

Apparently I like green Ducknut.


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## PG350 (Jan 19, 2012)

I did not foam under my deck but did make it air tight in Hope's it will hold air and act as floatation.


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## Wasy_ (Jun 30, 2018)

This also makes me want to add a single fiberglassed foam stringer down the middle.


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## JPizzle (Nov 9, 2017)

I was planning to redo a Johnson skiff before I bought my J16, might still do it. My plan was the following:
Keep the middle bench
Do not add any stringers or raised floor
put in front bulkhead and casting deck, have foam up at front of bow, exposed up off the floor
In the rear, do back deck with bulkheads and have foam in each rear corner. 
about 60% of the foam in the rear and 40% of foam in front, hoping to float somewhat level if ever needed. 

My Carsten duck boat has foam in each ends under the deck and is pinned in place with the spud pole sleeve. It is exposed to get wet, but being open the air, doesn't asborb and can dry out. 

Might not have been the best look wise, but this was to be a simple skiff and not have to worry about it.


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## DuckNut (Apr 3, 2009)

PG350 said:


> I did not foam under my deck but did make it air tight in Hope's it will hold air and act as floatation.


You are running a mile off shore and hit a dead head punching a hole in the hull and she turns over.

Now what?


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## Wasy_ (Jun 30, 2018)

DuckNut said:


> You are running a mile off shore and hit a dead head punching a hole in the hull and she turns over.
> 
> Now what?


See I wouldn't be running a mile offshore with this. But. There's alot of shit in my local waters that regularly ruins many peoples days and lives. That's why Id really like to foam fill


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## DuckNut (Apr 3, 2009)

Wasy_ said:


> See I wouldn't be running a mile offshore with this. But. There's alot of shit in my local waters that regularly ruins many peoples days and lives. That's why Id really like to foam fill


Did you read this thread yet? tells you how to do it.
https://www.microskiff.com/threads/foam-flotation-questions.73238/


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## Wasy_ (Jun 30, 2018)

DuckNut said:


> Did you read this thread yet? tells you how to do it.
> https://www.microskiff.com/threads/foam-flotation-questions.73238/


Yes I did. Thank you very much.


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## PG350 (Jan 19, 2012)

DuckNut said:


> You are running a mile off shore and hit a dead head punching a hole in the hull and she turns over.
> 
> Now what?


Life vest and bean bag chairs. . Actually I never fish outside Charlotte Harbor in my boats. Have friends with really nice off shore rigs.


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## DuckNut (Apr 3, 2009)

PG350 said:


> Life vest and bean bag chairs. . Actually I never fish outside Charlotte Harbor in my boats. Have friends with really nice off shore rigs.


I think you missed the point.


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## PG350 (Jan 19, 2012)

DuckNut said:


> I think you missed the point.


Must have.


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## DuckNut (Apr 3, 2009)

PG350 said:


> Must have.


You are driving along anywhere you travel, hit a dead head, punch hole in boat and sink.

Doesn't have to be offshore, happens inshore as well.


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## PG350 (Jan 19, 2012)

DuckNut said:


> You are driving along anywhere you travel, hit a dead head, punch hole in boat and sink.
> 
> Doesn't have to be offshore, happens inshore as well.


That would suck. Then I would have to walk the flats home. lol.


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## JPizzle (Nov 9, 2017)

We were running the channel in Pine Island in my 16' Hewes years ago near Cabbage Key and saw one of the old I beam markers that must have rusted off and broke. The remaining stem of the marker was just a few inches below the water and I happened to notice it while driving by as I thought it was a triple tail. Could have destroyed our boat and probably killed someone as we were on full plane. Stuff happens when you aren't expecting it.


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