North River - Removing foam from under floor advice

[Trigger05-11]

I have a 19 foot 2001 North River Sportster. I have never had the floor out. It has marine plywood wrapped in the vinyl. All original and super solid. Always covered and fished in fresh water.

Tomorrow I am going to take the floor out. I anticipate the water logged foam that people talk about under the floor. Does anyone have any experience, pointers or suggestions for removing it? All pointers and help are greatly appreciated.

Thanks!

[HntnFsh]

Do a quick search on Ifish. This has been talked about a lot over there. I am thinking an oscillating multi tool will be a big help. Also a variety of scrapers.
 

[Blacklab]

Power washer

[h2ofowlr]

I removed all of my foam out of my 19' Alumaweld.  I had used a putty knife for most of it.  I removed about 300lbs of water logged foam.  Lost of talk about it on IFish.  Different techniques and what others have done.  Those that have had water logged foam from the salt really have had some work to do when they see all the pitting in the aluminum.

[Irish_hunter93]

Best thing I found.

Grab a cordless drill, battery charger, shop vac and a handful of the quick change long rigid and flexible extensions, and some wire bristle brushes. Run your shop vac and hit the foam with the wire bristle brush, turns it into a powder that just goes into your shop vac.

Makes a frustrating project easy.

[Irish_hunter93]

In the case of my boat, a weldcraft, I took it out one day fishing and I had a friend of mine in the boat who was rather heavy set, but I noticed a substantial loss in top end speed and I noticed the  boat took longer to get up on step, and I also had noticed I was burning more fuel than normal.

I decided to give my friend the benefit of the doubt and pull my floorboards, in my case, I had waterlogged foam.

The foam itself is a closed cell expanding 2 part mixed foam that gets injected into the boat with floorboards on (per manufacturer when I called to pick their brain).

I had to do it myself, because unfortunately with weldcraft, 1st owner gets a lifetime warranty, 2nd owner gets nothing. I got the short end of the stick as a second owner.

What happened to mine, on installation of the foam, some of it over expanded into a couple of drain channels, and essentially blocked them off.


I had to cut a portion of the aluminum out underneath to get to the drain in question.


Called up weldcraft and went over blueprints and engineering drawings, worked with their engineers to figure out where I could cut a section away that wouldn't hurt structure.


Found my point, cut my access patch in and went to town on getting the foam out.



Got.it cleared and did a re-pour of the 2 part foam, wanting to keep things basically stock the way they came..... we'll, that bit me as I had to remove more foam all over again....



As it sits now, I took most of the foam out, drilled extra drain holes being mindful of structure, and riveted my access plate back in. I pull my floorboard once a year, pop my access plate under the floor out, make sure it's clear, rivet it back in and put my board back down and everything is good to go.



Long story short, ditch the foam and don't look back.


I'll post pictures.

[Irish_hunter93]

Start of project

[Irish_hunter93]

Access cutout in floor "non structural" substructure (right hand side of picture) and access holes cut by rear splashwell

[Irish_hunter93]

Re pour, that I ultimately wound up re-doing later, you can see my access plate riveted back in place.

Welded two tabs on wither side of the plate that would overlap underneath the structure so the plate would fit flush.

[Irish_hunter93]

Re-removing pour foam.


You can see the drill extensions I'm talking about in this picture attached to the drill.


Flexible ones work great as well

[Irish_hunter93]

Finished.


I also took the time to get corrosion off the structure underneath and prime with I believe a zinc phosphate marine primer.



Long story short, take the foam out and be done

[Irish_hunter93]

Hope this helps

[Crunchy]

Glad my NR is foam free.  Does not look like fun.

[jamesfromseattle]

A tip I saw in a boatbuilding book is to shove it full of cheap lifejackets. Does the same thing as foam (takes up space that water can't fill if your boat sinks) but they're easy to take out and inspect.

[Trigger05-11]

Thank you all so much. Great information!! Going to get started today.

[huntnphool]

Glad my NR is foam free.  Does not look like fun.

+1

 I’d also make the drain holes in each segmented compartment bigger while you are in there. This helps them from getting clogged and standing water being trapped under your floor.

[Trigger05-11]

I started pulling the floor up. We have foam from the bow all the way to the stern. It’s in there super tight and appears difficult to impossible for water to flow under the floor. I can’t believe it.

[huntnphool]

I started pulling the floor up. We have foam from the bow all the way to the stern. It’s in there super tight and appears difficult to impossible for water to flow under the floor. I can’t believe it.

 Legally that’s the way it’s supposed to be, they did what they had to in order to comply.

[Trigger05-11]

Got it all out. Two enclosed boxes the length of the hull are filled with foam.  Couldn’t get it out without cutting into the aluminum. No glue or anything. It came out really easy with little crow bars and putty knives. Was much easier than I expected.

Found three soft spots in the wood floor. I think we will swap out the floor for diamond plate next year.

Thanks for the help!

[HntnFsh]

Looks really good. Glad it wasnt too bad a job!

[Stein]

All boats under a certain length are required to be virtually unsinkable, i think it's 20'?  They have foam in them so if you get swamped you have something to hold onto while you wait for rescue.  Over 20', well, it's going to the bottom.

There are two types of 2-part foam, the cheap expanding stuff and the really expensive stuff that can be in the water for years without absorbing water.  People also put other stuff under there to provide some flotation.