Restoration Of Fiberglass Boat

Hello - I'm new to this adventure of boat restoration so please forgive me if my questions seem to the learned - fundamental.

I have an older 16ft Chrysler Charger 183 fiberglass boat - weighed in about 300 lbs overweight - determined that the floor was wet/rotted and the foam used in original construction was waterlogged. The floor (save for a 3 inch strip around the perimeter where it is fiberglassed to the hull) has been removed and all the foam has been removed --- now to restore this.

Just as general information - the boat will be on a trailer / outside and covered when not in use - Winter (temperatures here drop to -20 to -25 degrees celcius = -5 to -10 F) Summer runs in the plus 20 to 30 degrees celcius ( 70 to 90 F )

Questions

Is the foam required for structural integrity (along with safety floatation needs) and can current closed cell foam kits be used.

Does the new floor need to be "marine grade plywood" and whatever wood I use - does it need to be sealed or fiberglassed on both sides - if sealed - what should be used.

I was planning on screwing the new floor to the 3 inch strips I left in place and then giving the fiberglass (existing) and light grind or rough up and then using fiberglass mat to readhere the new floor to the hull sides --- Does that seem reasonable.

Any suggestions are most welcome and your input willbe greatly appreciated.

Thank you

 

No you don't need to install the foam again, but many think it's a good idea. Closed cell foam is the only foam to use.

It's wise to use marine grade plywood in the replacement sole, though many use a BCX sheet, available from their local lumber store, but it's weaker and prone to failure because of lower panel construction requirements in these grades of plywood, but fortunately the sole in most boats isn't highly loaded.

You can lay the new piece(s) on the flange created by the old sole tabbing, but the support stringers under the sole will need to be shimmed up the thickness of the removed plywood, to accommodate the height difference. This can be a tedious pain in the butt, so most just tab it back it where it was, reusing the old tabbing (flange) to marry the old to the new. Taper the old and new work together.

Yes, you need to coat both sides and especially the end grain of all the new pieces going in the boat, with particular attention to all cutouts and screw holes. This is the reason the original failed, not enough goo.

Epoxy is the usual choice for this type of driveway repair, for several reasons. It's actually waterproof, while polyester (boat resin at the local store) isn't, it's way stronger, doesn't smell or gas off harsh fumes and is easy to work with. Epoxy will actually seal and waterproof the wood. Epoxy does cost more then polyester resin, but you don't need as much because it so much stronger. Lastly if using epoxy, you don't need mat, just use cloth or knitted fabrics.

 

Hello Par - thank you for your advice --- a few questions.

The hull of the boat has NO ribs or other structural cross or long members save for the keel itself - with the old foam removed - there is nothing there but the inside of the hull. I think Chrysler used the foam to give the hull fiberglass - integrity and strength while maintaining a very moderate amount of flexibility (the old open cell foam is softer then the new closed cell stuff ).

If you ran the boat up on trailer rollers without support - I doubt it would take much to crack the hull - so if I do not RE-foam it - then I think I need to create some form of hull support system in its place -- you views. ( will try to get some pictures to post)

I like the idea of the epoxy resin vs polyester - sounds easier. Where would I likely source this product.

When the new sole (floor) is installed - how would I adhere / seal the epoxy coated floor to the old strips and sides of the hull (fiberglass) and around the transom well (where the drain plug is) as this area will most certainly see water at some time.

You mention I need not use matting - so fiberglass cloth (woven) would be suitable???

 

If it's one of the old Chryslers then it has a humongously thick hull shell and really doesn't need anything else.

It would be a wise thing to use the search tool on this site, looking for "sole replacement" floor replacement" stringer replacement" etc. This is an often covered subject and you need to brush up on techniques and materials.

Download the "user's guide" at Westsystem.com and Systemthree.com. These epoxy formulators have a host of information about how to use their products, but the techniques and methods apply to all epoxy work. Bateau.com is a good source for epoxy and fabrics. Also have a look at epoxyproducts.com for information and materials.

The old open cell foam was purely floatation and didn't have any structural value. Contrary to what you might think, I'll bet you could strip the boat of everything and the hull shell wouldn't move much on the trailer. It's probably 3/8" to a 1/2" in most places.

 

Hello Par - thank you for all your wisdom... I have attached a few pictures of the inside of the hull (floor and foam removed - save for up in the bow area - have not got that far yet) hopefully you can make out the small strip I left around the perimeter -- along the sides - it is just an inch off the bottom of the hull. When I step into the boat - the hull flexes easily (enough for the "crud" on the outside to flake off the hull ) and from the pictures you can see there is only a keel support built into the hull fiberglass structure.

The boat is a 1967 Chrysler Charger Hydro-Vee --- found an article on the web and it states that the new design (the first actually designed by Chrysler and should mark the end of the "Lone Star" name from the original purchase in 1965) is significantly quieter due to the "new patented" Foam Pac design - where the Hull is filled with Polyethylene foam which provides for great structural strength along with floatation...... While the foam in and of itself is not structural - when injected and confined in a cavity - it becomes structural --

Thank you again and the tips on the wood and expoxy and the links are great.

 

To risk re-post, do not reinstall the foam unless you want someone else to perform the task you are presently undertaking. The space beneath your soul should be left open. If you are concerned with sinking if you hit a reef or container, you can always seal the area airtight with epoxy, But this is overkill. You have an "old glass" boat that will bounce off of all but the sharpest of rocks. I usually install a nice drain hole in the bulkheads down the "keel" for when the floor eventually fails(many years from now).

 

Oh and in 67 they were still using old glass formula, You may never see a blister on your boat. Check it out, at the time humans had not figured out how strong fiberglass was, so the designs tended to lean towards excess. You have a sound hull that will never need any reinforcements other than some little bulkheads to catch your soul.

The easiest way to fit bulkheads I have found uses Popsicle sticks and a glue gun.
lightly screw a block of wood where you need your bulkhead and start gluing the sticks(or well cut scraps) along the hull. When you have created the outline of your bulkhead unscrew the sticks and transfer your new pattern to your plywood.

Use string lines to determine floor level on your patterns before/while, you create them, These marks make the straight line on your plywood that catches the floor.

 

one more thing, the add said:when injected and confined in a cavity - it becomes structural --

ONLY Structural because it supported the floor without fitting bulkheads. even closed cell foam sucks eventually.