Rolling a boat for 'upside down' work

[ian_upton]

A buddy of mine had his 20 foot Bertram turned over when the bottom was being done.

On my 25 Bertram, all of the deck 'coring' is not covered with an inner fiberglass skin.

To stiffen up the deck and replace some questionable core, would it be easier in the long run to flip the boat over and work or do everything upside down?

Ian.

[rwatson]

I dont know a lot about the Bertram, but upside down glassing is a real awkward thing.
One idea that sprang to mind is to lay up glass sheets on a smooth surface, and epoxy the 'sheets' that have been cut to shape onto the underside.
You could then use some temporary supports to hold it in place.
You could even use an inflatable bag(s) for the last 6 inches to make sure even pressure is applied all over.
Miight be a bit easier than flipping, thoug hthat is a viable option

[PAR]

Of course down hand work is preferred to vertical and especially overhead, but it's only practical if you have enough to warrant stripping the boat of everything.

If your boat is basically complete, then it's not practical to remove, tank(s), engine(s) and everything not bolted down, build a contraption to hold the boat inverted, etc., just to skin a new headliner (for example). If your boat is just a shell, then rolling it is a consideration, but overhead work can be done, it's just more difficult.

One trick I use on overhead work is to very lightly apply spray adhesive to the surface, then stick the fabric to that. It will hold it until you wet out and it can be repositioned too. Another method is to wet out the surface and wait until this coat gets quite tacky, then apply the fabric which will then stay stuck.

[ian_upton]

Thanks guys...

The boat is basically a shell, engines are removed, fuel tanks are empty. All wiring has been removed. Just getting prepped for paint, etc.

I might talk to the fiberglass guy and see what he thinks.

Ian.

[the1much]

flip it,, a couple chain hoists, pick it up, and as you let it down, pull 1 end under the other, it sets it down nice and easy. i've done it with a 23 footer and set it upside down on barrels and 4x4's.,,,,plus,,,fiberglass in ya hair makes ya bald

[Geoh]

I have a coupla 15' jet boat hulls that i have the same problem want to roll and repair bottom damage no engines...thinking back trailer in the water and float off sideways to the shore... strap a coupla 4x4 cross ways and flip with the truck from shore...than load upside dn on trailer...
George

[Kaptin-Jer]

Turning a boat is not difficult. Think in terms of a one-off mold in reverse. There are a number of ways to accomplish it. I have turned a 78' hull with one other person and turned a 26' wood walk around in it's own space. Check out all the books that describe fiberglass hull building. They all show various methods of flipping a hull.

[fiberglass jack]

use the spray glue 3m super 77 will breck down in the resin, all you need to do is prep the area and then cut the mat or cloth to size place it and then wet it out lightly to much resin and it will fall down, do one layer at a time, you will want to use a small roller for this its easier than a brush as a brush the resin will flow down your arm, in the corners you might need to use a paste, its hard to say what to do with out seeing it, fliping the boat is alot more work then glassing overhead, just my opion

[PAR]

3M 77 is what I use and it beats rolling a boat. I'll be done before you get it rolled.

[rwatson]

If any of the underneath is going to be close to someones head, its usefull to put a layer of peel ply on over the fibreglass cloth to make sure you get a satin smooth, professional looking, sharp protrusion free surface that will require no sanding afterwards. If you think laying fibreglass upside down is bad news, try sanding it.
Just apply say, metre square "patches" after the section is wet out.
If you are not keen on creating smooth sheets of fibreglass to cut and glue up inside the boat, a good grade of marine ply would be attractive and easy to place. Nice coat of varnish before you attach it, and there is a great finish.
Obviously this doesnt have to be structural, or they would have put it in already?

[OGM]

I've done verticle and upside down work by wetting out the glass on carboard board covered with wax paper and then placing it on the over head area. Make sure you wet the area over head first. I then taped the cardboard with the glass in place and used a roller to work out any air. It worked pretty good - much easier than applying resin and working the air out upside down.