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replacing wet foam in an 84 2020


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#1 fretz

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Posted 20 September 2017 - 08:41 AM

Hope you all have had a great summer boating!  We got allot of use out of our classic robalo and hopefully stretch the season well into october.  However it is time to work up the to-do list for next year.

 

Last winter i replaced the aft floor and re-did the scuppers.  Part of the project was removing all of the wet foam and re-pouring new flotation foam.  We couldnt be happier with the results.

 

With the law of unintended consequences always at play the boat now floats noticeably higher in the transom.  So the logical solution is to continue cutting up the floor and replacing the soggy foam.  

 

My question for all of you is...

 

How structural is that foam between the hull and deck?  

 

If i cut up the inside of the forward fish well and remove it is there any support for the hull besides the foam sandwiched between the 2 skins?

 

  • the plan is to cut the glass
  • grind the cut so that i can tabb it back in before i remove 
  • remove the floor
  • remove the foam
  • let sit for a few months with a dehumidifier
  • glass the floor back in place
  • Pour new foam through a few holes
  • plug the holes

 

Im not worried about the "cosmetics" in the forward fishwells and the entire floor will be covered with new non skid or something like raptor deck.

 

I just want a better idea of what is going on between the hull and deck.  If there is a specific density foam or something that i can inject with lower expansion properties please let me know.

 

Thanks!

 

Chris

 

 

 

 



#2 2-N-TOW

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Posted 20 September 2017 - 07:48 PM

2 lb foam is what is used below decks on boats.  What structural support it provides for the decks is really secondary since it's primary  purpose is floatation.   It does provide sound deadening and does help support the deck a little.  Bottom line, removing the foam should not have impact structural support.

 

So you plan on tabbing the deck on the top side only?  I would lay up some flat tabs out of fiberglass cloth, then attach them to the bottom of the remaining deck with a thickened cabosil/resin mix and pull tight with sheet rock screws.  Once set, remove the screws.  When it is time to re-install the deck, it will sit on the tabs and then you can glass the joint back together from the topside and not have to fight working around the tabs.


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1988 2160 / 2003 Evinrude 225

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#3 fretz

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Posted 21 September 2017 - 07:08 AM

Thanks for the tab suggestion.

 

I knew something would have to be done but figured the solution would present itself at the time.

 

So you dont think the foam is structural like a boston whaler?

 

Im concerned that i will have voids when i go to re-pour it 



#4 2-N-TOW

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Posted 21 September 2017 - 09:04 PM

No, it is nothing like a whaler.  I would love to know the hull thickness on a whaler compared to that of a Robalo.  I do know for a fact the glass in the hull bottom 12 inches forward of the transom is about 1/2" thick.  These hulls are strong enough with the frames and stringers that the foam does contribute to the overall strength.  Once the deck is in place and glassed to the coamings, you now have a ridgid grid system below deck surrounded by a box beam (hull and deck structure).  This results in a very strong hull.

 

Regarding potential voids when re-pouring the foam...I would foam the open areas below deck prior to installing the deck.  You can do multiple small pours to fill in the areas until the expanded foam is slightly above the floor level.  Once it is hard, use a hand saw to trim it flat so it is just below the bottom of the deck.  Brush a coat of fiberglass resin over the cut foam to seal the exposed cell structure, then install the deck.


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#5 fretz

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Posted 25 October 2017 - 07:15 AM

We used a hole saw in the forward fish boxes and the foam is dry.  Dug down about 4".  I'll do a 2nd large hole directly in front of the console once its inside the garage to dig to the centerline and confirm.  

 

If thats the case i have to adjust the waterline one more time.  Has anyone replaced the core in the lids for the forward fishwells?  i know they are soggy so i should get a few pounds out that way too if i use corecell.

 

On a different note the teleflex cable broke while we were pulling the boat for the winter.  There is a 150 merc for power.  would you replace the teleflex cable or upgrade to hydraulic steering?  The merc is an 03 so i would have the steering for the next motor when that day comes.

 

Thanks!



#6 2-N-TOW

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Posted 25 October 2017 - 01:03 PM

There is no comparison between hydraulic and teleflex steering.  Hydraulic has no torque feeback which is really nice when you are running any distance.


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#7 fretz

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Posted 02 January 2018 - 11:55 AM

I was able to cut open the floor and dig down to the bottom.  Its deep up there leading me to believe that any water in the hull is sitting up in the bow not draining aft to my bilge pump when in the water.

 

The foam is dry till the last 4-6" which is soaked.  So...  how crazy do i want to get here?  Should i remove the floors in the fish boxes and get it all out?  I could just leave it open for the next 2 months and see if it all evaporates.  I could help things with a de-humidifier too.  When i put it back together should i add a 2nd bilge pump up there?

 

I was hoping for an itch free spring...   not likely at this juncture.

 



#8 fretz

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Posted 02 January 2018 - 12:07 PM

IMG 1038
 
Back inside.  Hopefully one classic influences the other.
 
IMG 1031
 
Cut a nice access infront of the console.  Foam was dry
 
IMG 1104
 
Dug to the bottom and found standing water again...


#9 2-N-TOW

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Posted 03 January 2018 - 08:03 AM

I would try the least invasive approach first.

 

Raise the trailer tongue so the water flows back to the fish box.  Get rid of the accumulated water from the hole, then see how long it takes to fill up again.  Repeat the process, tracking if the amount of water migrating back to the hole diminishes over time (it should).

 

If possible, get some type of flexible pvc or plastic hose that is stiff enough to sharpen the edge of one end to make a cutting edge/blade, then start boring a hole along both sides of the raised area along the keel (I do not recall there being a stringer there...just a glassed over piece of tubing).  This will allow water to move back to the dug out place faster instead of having to "seep" through the foam/hull interface.  The hole does not have to be very large.  Just go forward as far as possible to speed up the draining process.

 

Once this is done and if you are happy with the results, glass a mounting pad in the opening, install a bilge pump, and enjoy the rest of the winter with no additional glass cutting involved!

 

One day I have to do the same thing to my boat as I know there is water trapped forward of the coffin box.  I am trying to delay it until we have built the new house, which will include a detached shop big enough to store the boat inside.


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