1969 Chris Craft Roamer 46 Refit: Bullet-proof Cabin Top

By February 2013, it was time to take the next step and get the cabin top covered with new fiber reinforced plastic. The plan was to put one layer of 1708 biaxial fiberglass over the salon roof hatch repair area, then cover the whole cabin top with a single monolithic layer of the same material. Modern biaxial cloth is a huge technological advance over anything that was available in the late 1960s, offering much greater strength than even heavy woven roving with a much, much lighter final layup. Since the original Roamer 46 cabin top FRP layup was only three layers of light woven boat cloth (and very resin heavy in spots), this new FRP skin should greatly strengthen the roof. No more collapsed hatches from broken roof frames and 3″ fiberglass tape!

On the big day, my fairing crew boss showed up with a surprise (albeit an expensive one): several yards of biaxial Kevlar cloth. He felt this would be the best option for the first layer over the salon roof hatch repair and for the base of the windshield.

I’ve looked at the original spec sheet for these Chris Craft Roamers, and I can say for an absolute fact that “bullet-proof cabin top” was NOT a factory option. But it will be on mine! 😉

Previous repair to the base of the windshield.

The repair was done in lightweight boat cloth and it was dry in spots. There was another repair to the starboard side but not as extensive as this. We decided the best approach would be to apply a new layer of FRP from the bow seat, over the windshield base support area, and all the way to the dashboard.

We also stripped off the remainder of the gelcoat on the aft end of the cabin top sides.

The helm station door frames still needs to be built and tied into the cabin top, but I haven’t had time to do it yet. I’ve also been looking for a competent carpenter who can do the work but thus far haven’t had any luck. I’ve found competent carpenters who are too busy to focus on a big project. Incompetent ones, needless to say, are everywhere and ready to work…but no thank you.

1708 bi-axial fiberglass is pretty stuff.

Random oriented mat on one side stitched to 90* bi-axial on the other.

Bi-axial Kevlar Fabric is Bullet-proof (and almost scissor-proof!!)

My Wiss 1225 scissors are pretty good, but that Kevlar fabric put up a good fight. It’s incredibly tough stuff, and we haven’t even saturated it in epoxy yet!

Boatamalans* brushing US Composites 635 epoxy thickened with wood flour over the hatch seams and other imperfections.

We’ll brush and squeegee wood flour-thickened epoxy into all of the blisters I documented while stripping the cabin top. Doing so fills the blisters and gives the FRP layer a solid surface to bond to. If we just ‘glassed over the blisters, we’d get air bubbles under the new FRP.

* Boatamalan: portmanteau indicating highly skilled boat workers of Central American origin. 😉

Rolling on the US Composites 635 epoxy to wet out the new cabin top plywood and old fiberglass roof.

Bullet-proof Chris Craft

Ruis, the head Boatamalan, tells me that they use Kevlar and 1708 fiberglass bi-axial on the bottoms of Weaver Boatworks’ multi-million dollar sportfish boats. Apparently, the manager at Weaver took a sample of their bottom layup to the shooting range and set it up as a target. Later analysis showed that .308 rounds would penetrate two layers of fiberglass, but they could not pass through one layer of 1708 over Kevlar. The ‘glass layer was damaged, but the Kevlar stopped the bullet.

OK, I’ve been informed that “bullet-proof” is the incorrect term, since a modern .50 caliber machine gun might (with some effort) breach the fabric. Bullet-resistant Chris Craft is apparently the preferred term.

That’s still pretty freakin’ kewl! 😉

Wetting out the 1708 bi-axial fiberglass.

Once a big fiberglass job like this begins, everybody has to move fast until it’s over.

Unfortunately, I was unable to take pictures after this because I was the official epoxy mixer. We went through 20 half-gallon batches that day.

After putting the 1708 biaxial layer down all the way to the bow seat, we cut more Kevlar and 1708 and applied it to the base of the windshield. By the time that was done, the epoxy in the hatch area had set up.

Time for fairing compound!

US Composites 635 epoxy + 3m Microballoons + Cabosil (5:4 ratio) = world’s best fairing compound.

After the FRP layer was done, I continued mixing resin for the fairing compound.

Since we’re using the same epoxy for the FRP layup as the fairing compound, chemical compatibility is perfect and so is the chemical bond between layers. When we sand the fairing compound layer and apply more compound to the low spots, we won’t break the fibers that give the FRP layer strength. This approach is also less labor intensive than applying the FRP then sanding it to apply fairing compound.

My secret resin makin’ lair. What a dusty, sticky mess!

Frosted goodness.

The evil cracks and weak spots from the original FRP layup are forever entombed…in modern epoxy, Kevlar, fiberglass and glass microballoons.

Once the epoxy cures, we’re ready for the fairing crew!

That was a very long day…and it happened only two weeks ago.

Next up on our 1969 Chris Craft Roamer 46 Refit: The Helm Station/Dashboard.

Advertisements

4 comments on “1969 Chris Craft Roamer 46 Refit: Bullet-proof Cabin Top

  1. 1969roamer46 says:

    That’s a fine looking Marinette you’ve got there. Very nicely done!
    Aquia Harbour is just a bit south of my home port. If you’re ever in the area, let me know!
    btw, what powers your Marinette?

  2. gratefultwo says:

    I did a complete refit on a 39 ft. Marinette in 2011. I would be lost with all this fiberglass work. My wife, friends and I thought we did alot of work – floated the Marinette from Aquia Harbour, Virginia to Hamilton, Ontario Canada before we took it apart. You humble us with this effort, I want to drive down and see this 46….

  3. Outstanding analysis and even more outstanding restoration work.
    Only wondering iffin’ you performed adequate wind tunnel testing – fuel efficiency/stability considerations no?
    Great job!!
    -E

    • 1969roamer46 says:

      Thanks, E!
      On fuel efficiency and stability, I figure a roof you can walk on without the hatch failing is worth the extra 200lbs or so. Heck, we get that much extra weight up topside when we load the beer fridge for a weekend out! 😉

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s