1969 Chris Craft Roamer 46 Refit: Insulating and Installing the Port Salon Panels

I wrapped up the varnish on the ceiling panels that go under the port side deck, then insulated the backside and installed them all.

I’m working in the port aft corner of the salon

The last ceiling panel is varnished, drilled, and ready for insulation

The backside gets wetted out with epoxy

Since I had epoxy mixed up, I glued and screwed all of the mahogany backing cleats in place.

Buffalo Batt insulation gets pressed in place

The forward ceiling panel also got insulated

And the middle panel, too

Next day…they’re ready to install

Next day, the forward panel is glued and screwed in place

The insulated envelope

The hull and deck are covered in spray foam insulation rated at R7. Then there’s the air gap, with the backside of each wooden panel insulated with Buffalo Batt, which provides an additional R3 insulation. The boat should be cozy in summer or winter with all of this insulation. I hope it’s worth the extra effort.

The middle panel was next

One more to go

The last panel goes here

The contact areas got wetted out with epoxy, then topped with wood flour-thickened epoxy

Boom

And that’s a wrap

With the insulation envelope done on the port side of the galley and salon, I can get to work on the salon cabinetry there.

Next up in our 1969 Chris Craft Roamer 46 Refit: Cutting and fitting the Port Salon Cabinet

1969 Chris Craft Roamer 46 Refit: Installing the Bow Seat Window Mahogany Panels

Back in May 2015, I made the bow seat window interior panels. But they sat gathering dust as other priorities got done, like installing the port and starboard engines, installing the helm windshield frame, painting the aft head. staining and varnishing the salon…it’s been a busy year. But I’ve got to get the exterior weatherproof, so it’s time to install those bow seat interior panels and get the windows in.

Panels cut and beveled in May 2015…ready for ICA clear coat

Mahogany panels coated with ICA in the spray booth

Ribbon stripe is very pronounced in new mahogany under the bright spray booth lights

“Paint adjustment” to accommodate Motion Windows oversizing 2/3 of the window frames

Another “paint adjustment” for Motion’s oversized window and some spray foam insulation had to be trimmed

I had to take a grinder to two of the window openings because Motion Windows tends to make their frames too big. It doesn’t seem to matter whether I send them dimensions in text form, drawings, or even templates of the window holes cut from 1/4″ luan plywood with explicit instructions to NOT make the frame bigger than the template…Motion Windows STILL makes 2 out of 3 frames too big. But enough of that nonsense. It’s time to get the panels installed!

Step 1: wet out the backside of the mahogany panel with West System epoxy

I wetted out the panel around the window opening itself, too, so there’s plenty of epoxy soaked into the wood. Since I’m using screwless construction here, the epoxy bond has to be very strong.

70% wood flour and 30% cabosil used to thicken the epoxy that will fill the gaps

Slather the thickened epoxy on both panels

Clamp in place…good squeeze out at the top

Need some creativity when clamping the corners

I used a long mahogany board pulled from the pile to push the long edge of the panel up tight to the side panel.

Let it sit overnight

Looking good!

Cut edges will wick water and start to rot if the windows ever leak

The shot above shows the joint between the new panel and the painted bow seat window opening. If the caulk that seals the window ever leaks, water might be able to wick into the unsealed plywood edge and start rotting out the panel.

I fully saturated the cut edges with epoxy so water can never get into the panel

Saturating the edge and the joint with epoxy might be overkill, but I never want to have to deal with rotten plywood again. The down-side to this approach is that once the epoxy is applied, I have to wait until the next day for it to cure. Fortunately, there’s lots of other stuff to do on the boat. The following day, I installed the window.

Tape off window frame in preparation for Sikaflex 291 LOT caulk

Tape around the window frame catches most of the squeezed out caulk

Use a squeegee to remove most of the caulk, then pull the tape and clean up

Done!

I can’t wait to get all of the windows in so I can wash the boat. All of the wood and sanding dust makes the brand new paint look like hell.

Center panel, repeat the process

Clamp and come back the next day

Looking good!

Good epoxy squeeze-out means the panel is fully bonded to the substrate. The following day, I sealed the cut edges with epoxy, and the day after that I installed the window.

Tape off the center window for caulk

After wiping the flange with alcohol, I’m ready to run a heavy bead of caulk

A nice, heavy bead of Sikaflex 291 LOT

Good squeeze-out all around means 100% contact

Use a squeegee to clean up most of the caulk

Pull the tape and wipe down with kerosene to remove Sikaflex residue

Done!

The up-side to this approach is that I believe I will never again have to deal with rotten plywood around these windows. The down-side is that it’s very time consuming. Installing two panels and two windows consumed three days. I’ll have to wrap up the last window in the next go-round.

Next up in our 1969 Chris Craft Roamer 46 Refit: Completing the Bow Seat Window Installation

1969 Chris Craft Roamer 46 Refit: Aft Stateroom Wall Panel Install

Since the insulated galley wall install went pretty well, I decided to try the process out on some of the pretty African mahogany panels that go around the aft stateroom porthole openings.

1/4″ African mahogany panel finished in ICA base-coat clear

I added a cleat to secure the leading edge of the new panel to the bathroom wall

I cut out notches to make space for the hull frames on the transom

As you can see in the pics, the back-side of the panel is still bare wood. The plan is to get the final fit right, then coat the backs and all edges with epoxy. The ICA coating on the face will allow me to wipe off any wet epoxy with an ethanol-soaked rag. With the panel fitting to the hull and interior wall, the next step involved the missus holding the panel in place while I marked the porthole openings from outside.

Cutting out the porthole openings

Two down…

Good test fit at the transom and window cut-outs

African mahogany panel-to-panel fit is good, too.

Epoxy coating and insulating the back of the panel

On the galley panel I installed recently to test my insulation plan, I used 3M spray-on contact cement to adhere the Buffalo Batt polyester nonwoven fabric insulation to the cured epoxy protecting the back of the panel. I figured I could save a step by applying the insulation as I roll on the sealing epoxy coat. The missus was a big help putting her craft skills to work cutting the insulation to size, leaving room for the attachment points.

Insulation applied to port and starboard panels, then pressed gently together until the epoxy cures

Epoxy drippage from edge sealing was caught by tape

Tape comes off clean, leaving the edges sealed with no residue or stains on the African mahogany

If I hadn’t already finished the front face with ICA base-coat, the epoxy would have bled under the tape and stained the pretty mahogany.

Ready for installation

Nice!

The dead air cavity between the insulated hull and the insulated interior panel

The insulation gurus all say that dead air space between the outer and inner layers of insulation significantly adds to insulating properties of the material. Hopefully, this approach is worth the effort.

Before I permanently install these panels, I need to assemble the portholes and get some other things done. So for now, the panels are sitting in place, out of the way, covered in plastic, and protected from abrasion. With the heat of summer making it too hot in the tent to work up top-side, I’m getting myself into the engine room next.

Next up in our 1969 Chris Craft Roamer 46 Refit: Gantry Time II!

1969 Chris Craft Roamer 46 Refit: 1st Galley Plywood Install

Back when I was first thinking about insulation, I figured I’d get the best bang for the buck with spray foam (R7 per inch) on the hull and cabin top and 1-1/2″ thick Buffalo Batt polyester nonwoven fabric (R3) on the backside of each plywood panel that faces the hull. That combination should stop condensation dead and keep conditioned air in the living spaces, where it belongs. With the spray foam done, I decided to make the plywood stack smaller and install a panel.

1/4″ marine doug fir ply, cut to size and epoxy sealed on the back-side and edges

Need to square away some wiring and install a couple more cleat attachment points

The big wire loom on the right is the main feed shore power line that will go to the isolation transformer in the V-berth.

3M contact cement ought to hold the Buffalo Batt in place

Rolling out and measuring the polyester nonwoven fabric

This stuff is a LOT nicer to work with than fiberglass. No itch, and since it’s a fabric it doesn’t lose fibers.

The polyester nonwoven fabric needs to fit between the cleats the panel will attach to

Hose on the contact cement

Press the insulation into position, leaving space for the cleat attachment points

Buffallo Batts are all in place

Shore power main feed and stbd running light wires are secured out of the way

Dead air space inside the cavity between insulation layers reportedly yields best results

Polyester nonwoven fabric breaks for the cleats

Nice fit! Done!

So, the lesson learned here (and in a lot of other instances) is that cutting the panel, slapping some primer on the back side and edges of the panel, and installing it (like Chris Craft did originally) would have taken maybe an hour. Doing it the way I did took a day, including an overnight curing process for the epoxy. Multiplying that out over the entire boat, I figure I’ll  have a literal month of Sundays added to the time the project will take to complete with this approach. It better be worth it. In any case, this one panel install gave me some ideas for how to improve the process that I’ll try out on the next panel.

Oh, and if anybody’s interested, I’ve got a low-hour set of Cummins 6CTA exhaust risers that I just listed for sale.

Next up in our 1969 Chris Craft Roamer 46 Refit: Aft Stateroom Wall Panel Install.

1969 Chris Craft Roamer 46 Refit: Spray Foam Insulation

After a whole lot of time prepping the boat for spray foam insulation, I decided DIY Tiger Foam was the best bang for the buck. I initially intended to have a pro come out and do it, but I couldn’t find one who had experience foaming a boat. There was also a wide gap between estimates: $2,000 from one contractor vs $3,500 from the other. Tiger Foam was $1,350 for two 600 board feet kits, including shipping, and its E-84 fire rating is better than what the pros were offering. Plus, I like the challenge of DIY so…

1200bf of Tiger Foam

Moving big things away from the hull

After moving the plywood stack up against the galley bulkhead and the track saw table to the center of the salon, I started taping the place up the 3M hand masking film.

Ready to spray foam

Plastic and cardboard protect everything in the aft stateroom

Overhead panels got taped to protect the ICA clear-coated African mahogany

under-side of the side decks are clean and prepped for foam

I taped off the vent hole up above before spraying began.

V-berth taped off

Stem to stern, she’s ready for foam!

Having read all sorts of comments, seen tons of youtube videos, and read the manual front-to-back several times, I knew for a fact that spray foam is temperature sensitive. There are all sorts of warnings about application when it’s too cold, which yields a foam mix that may not rise at all. But there are no warnings at all about application when it’s too hot…which pretty much describes this whole year since two days after winter ended. I mean, we went straight from snow to hot–it was 75 degrees two days after the last snowfall, and it’s been over 85 on many days pretty much since late April.

So, on the day I sprayed foam, overnight temps never went below 79. That’s good, because 70 degrees is the minimum recommended tank temp for the foam. But by 10am, it was over 100 inside the tent up topside. The tanks were on the warm side when I finally brought them inside the boat, suited up, and started spraying. What they don’t show you in all of the videos is the amount of foam that rains down from above–what a mess!

That said, the first tank didn’t quite get the coverage I expected. But I attribute that mostly to the tank being too warm. There’s a bit of a learning curve, too, with respect to petroleum jelly you use on the nozzles (hint: use lots, and keep reapplying it or the foam doesn’t exit the nozzle smoothly). It also takes a bit to figure out which nozzle to use and how hard to pull the trigger (hint: use round nozzles and a very low application rate to frame out the perimeter of very box section between frames, then the fan nozzle and a higher application rate to fill in the middle). There’s also the eye protection problem.

It was 90+ in the boat and sweat running in my eyes made the job that much harder. The goggles I used kept fogging up on the inside, and the spray foam was coating the outside. After ten minutes, I was basically spraying blind. Swapping out the old goggle lenses for new, the same pattern repeated. And unlike spraying in a house, like they show on all the videos, all of the nooks and crannies of the hull and deck framing make it especially important to be able to see what you’re doing.

But it worked. It’s not perfect, but I got foam!

3 layer, full-depth coverage in the overhead of the aft stateroom head

Fairly uniform coverage on the aft stateroom head walls

Aft stateroom head

Aft stateroom

Spray foam over original Chris Craft bitumastic coating should keep condensation down

Foamy goodness inside the hanging lockers

This locker has the new aluminum deck outboard, so that aluminum didn’t have any of the OEM bitumastic. I laid the foam on heavy in here, in three layers yielding 2″ thickness minimum.

More foam in another locker

Note the slightly yellow foam at the center of the overhead above–that’s from the first tank that was a bit too warm. It expanded well, but perhaps not 100%.

Salon overhead foamed in

Condensation-proof AND bullet proof salon top

Hull side and under-side of the side deck

V-berth overhead

When I finally wrapped up, it was late after a looong day.

Next up in our 1969 Chris Craft Roamer 46 Refit: 1st Galley Plywood Install

1969 Chris Craft Roamer 46 Refit: Prepping the V-berth for Foam Insulation

One-by-one, I’m knocking out the honey-do list toward getting the boat splashed this fall. There have been some set backs, like the ongoing windshield frame fiasco, that might make it impossible to splash this year. But I’m still going full speed ahead in the hope of getting back on track, hopefully before I run out of steam.

With the aft stateroom all prepped for insulation, next I’ve got to do some things to get the V-berth ready for foam. And in getting that stuff done, I found a surprise left behind by a woodworking sailor who worked on the boat for a couple of months in 2012 and sold his services as “good but slow.” I found a mess Mr. Good-but-slow left behind when I was cutting the interior panels for the galley windows, and as I’m revisiting each part of the boat that he touched, it seems that all of his work left something to be desired.

The v-berth concept

V-berth major walls installed by Mr. Good-but-slow and wrapped in cardboard

In the pic above, I pulled up the v-berth floors to vacuum out the bilge one last time before fastening everything down. There were some surprises awaiting me as I pulled up the floor panels.

Mr. Good-but-slow’s patented “floating wall” system

When the woodworker initially installed the wall, he had the panels bolted to the hull frames but not connected to the deck frames overhead. Instead, they were held in place between a series of mahogany blocks that sort of pinched the panel while permitting limited up and down movement. I’d given him wide amount of discretion on how to accomplish my concept for the v-berth, so I wasn’t upset with the approach. And I understood his theory that an overly rigid structure can catastrophically fail, so permitting some degree of movement can be a good thing, as in the case of viscous couplers used to make bridges earthquake-resistant. I also knew from talking to a former Navy ship engineer that in underwater mine testing of fiberglass hulls, the engineers determined that FRP joint failures were prone to happen when explosions happen nearby. But, I pointed out to Mr. Good-but-slow, an FRP hull to engine stringer joint is a different beast than 3/4″ marine plywood bolted to an aluminum hull and deck. And in any case, I have no intention of running my boat in waters containing mines. Having a bullet-proof cabin top is one thing…I don’t need mine-proof v-berth walls!

So, Mr. Good-but-slow followed my explicit instructions and bolted the v-berth panels to the mahogany that was bolted to the overhead deck frames. What I didn’t know was that he’d left the bottom end of the panels free-floating, too. In the pic above, you can see that the panel is sitting firmly on the floor framing but it’s fastened to nothing along the bottom. When I removed the two floor panels, I discovered that he had used the same pinch approach as he used on the top!

Three large mahogany blocks bolted under the floor frames

I stared at the three blocks in the pic above for a while, trying to figure out what their intended purpose was. In the end, I was stumped and decided Mr. Good-but-slow might have wanted them to support the center floor section (which lifts out), but the blocks are under the floor frames–they don’t have a rabbet cut out so the edge comes up to the top of the floor frames. Plus, they barely stick out far enough to support anything, even if they were high enough. Finally, Mr. Good-but-slow knew I was using rounded corners on the walls, so it’s unclear why the transverse wall he installed comes out so far that the longitudinal wall that will attach to it cannot land on the floor frame.

Geesh. Time to get busy.

Everything glued and screwed together

I was too busy to take step-wise pictures, but the shot above captures pretty much everything. First, I cut mahogany blocks and used epoxy to glue and screw them to the mahogany blocks Mr. Good-but-slow installed. I installed them so they’re high enough and stick out far enough to support the center floor panel. Next, I wetted out both sides of the lower end of the wall panel and saturated both floor panels along the end grain with epoxy. Then I used my Kreg Mini Jr pocket hole jig to drill screw holes, and I applied epoxy thickened with wood flour and cabosil along the joints, Next, I fastened the floor panels to the wall panel glue joint using pocket screws, which pull the whole assembly together tightly, and I fastened the floor panels to the aluminum floor frames. Next, I cut out a bit of the center floor section that will support the longitudinal wall, and glued and screwed it in place. Then, finally, I installed the solid mahogany corner piece that’s pre-coated with ICA basecoat clear.

The overhead plywood finally gets installed

I started the day only planning to install the overhead plywood in the v-berth, then get on with other projects. Instead, it was nearing the end of the day when I finally got the overhead piece installed.

Epoxy stains on unfinished plywood won’t matter

The v-berth wall finishes will be a combination of off-white painted surfaces, ICA-coated natural mahogany, and Whisper Walls fabric. Because there’s limited light in the forward compartment, we decided there should be a lot of surfaces in white. The walls here will be finished white or covered with foam-backed white fabric, so the epoxy stains on the okume ply aren’t a concern.

Done!

With the v-berth finally ready for spray foam insulation, the next step is waiting for the foam to arrive.

Next up in our 1969 Chris Craft Roamer 46 Refit: Spray Foam Insulation

1969 Chris Craft Roamer 46 Refit: Aft Stateroom Head Ceiling

There are many, many things going on all at once as I work through the issues on my helm station windshield frame. Getting the aft head done is one of those multi-step processes, and everything has to get done in a certain order. While we were getting the walls fiberglassed and faired, we’re also cutting and fitting plywood panels to use for the ceiling. In preparation for spray foam insulation, I also removed the original fiberglass insulation from overhead. As you can see in the pics below, there’s some of the tar-like adhesive Chris Craft used to attach the fiberglass remaining. But, according to the spray foam literature, the substrates don’t have to be perfect so long as they’re clean and well adhered.

Cheap luan ply makes good patterns

Breaking down a sheet of 1/4″ marine ply

My EurekaZone EZ-One woodworking center and track saw make it pretty easy to break down large panels. There’s no way I could do this with a conventional table saw.

Plastic guide strip shows exactly where the blade will cut

The track saw guide strips stick out a bit when new. You do the first trimming cut on scrap wood down the full length of the track, which cuts the plastic exactly to the edge of the saw blade kerf. Taping the guide before the trimming cut makes for a cleaner cut. From that point on, just align the guide strip edge with the start and end points of the cut.

Clamps on the underside hold the track tightly to the wood

Final cuts on the ceiling panels

After checking the fit of the panels in the aft head, we moved them up to the aft deck and applied fiberglass to what will become the inside surface.

FRP on the ceiling panels

We then applied home-made fairing compound when the epoxy resin became tacky

We’ll sand the fairing compound later and applying Alexseal 202 fairing compound, which is reportedly the best stuff to use in showers. Then we’ll sand the Alexseal and apply Buffalo Batt insulation (R3) to the backside of the panels, then glue and screw the panels into place. But first, in preparation for the spray foam insulation, I need to get all of the African mahogany pieces that will be attached to the overheads cut and installed. Word has it it’s much easier to install bulkheads and then spray foam than to spray foam and remove strips of it to install bulkheads.

Next up in our 1969 Chris Craft Roamer 46 Refit: Cutting and Installing Overhead Mahogany Plywood

1969 Chris Craft Roamer 46 Refit: Aft Stateroom Head Walls

I installed the aft stateroom bulkhead and main walls back in March and April, which was one of many big things that must happen if we’re going to splash the Roamer in the fall of 2015. The windshield saga may put a hitch in that plan, but I’m going full steam ahead on other things while I work on a resolution for the windshield problems.

After getting the aft stateroom walls installed, my Boatamalan painter asked why I don’t make the aft head into a giant shower: basically, fiberglass and fair the walls and ceiling, then bond the ceiling to the overhead frames and fillet the corners. Then, prime and paint with Awlgrip. You end up with a monolithic room with no cracks or seams for water vapor to hide in and support mold. They do this on the showers in the multimillion dollar sportfishermen that the Boatamalan makes at Weaver Boatworks (his day job), though their showers are much smaller than my aft head. I figure what’s good enough for a multimillion dollar Weaver boat ought to be OK for a Chris Craft Roamer refit.

Expensive little pile of materials

1810 biaxial fiberglass, a roll of Floor Guard (the blue corrugated plastic), four rolls of masking film, a bucket of wood flour, a gallon or two of epoxy resin, hardner, and some fancy-schmancy filler…$1800. A small price to pay for a bathroom that’ll make the missus happy. By the time we add in the Awlquik, 545 primer, and Awlgrip top coat (in an off-white eggshell color), reducer, and catalyst, materials for the aft head total $2500.

This AlexSeal product is the only fairing compound to use in showers

The Boatamalan says other fillers–even Awlfair–can end up having problems years down the road in a shower application. The Alexseal product, while eye-poppingly expensive, is worth every penny since we’ll never have to do it again.

Roamer bathroom w/jet bath > Weaver multimillion dollar boat w/shower 🙂

The challenge is, we have to fiberglass, fair, prime, and paint in a small boat bathroom (relative to your average house bathroom) while the jet bathtub is in the space. Taping off the tub with Floor Guard and setting it up on end out of the way, the Boatamalan hit the bulkhead and walls with the sander. In retrospect, if we’d thought of this approach earlier, we should not have beautifully finished the interior walls of the head with ICA base coat clear. It all got turned to some very expensive dust in preparation for fiberglassing the walls.

Sanded with 36 grit and ready for epoxy and 1810 biaxial fabric

First layer of 1810 fabric applied at the top

Second band of 1810 applied down to the floor

Looks like a good place for fillets

I’m a big fan of fillets.

Skim coat of fairing compound

Once the epoxy was tacky, we hot-coated it with home-made fairing compound using the same epoxy and a 70/30 mix of microballoons and cabosil to a stiff, whipped cream consistency. We did this when fairing the exterior as well, since it puts a layer of fairing compound between the sand paper and the glass fibers in the FRP matrix when the fairing process begins. The strength of FRP is in the fibers, so not breaking them makes for a stronger finished product.

Bulkhead wall coated in fiberglass, epoxy, and fairing compound

That’s a wrap for Step One in the aft stateroom bathroom. I’ve described before the complex order of operations for this refit, where seemingly unrelated and even trivial stuff has to get done before a bigger thing can get done. The order of operations as of right this second is:

Sand walls
Apply Alexseal fairing compound (wait to cure)
Make ceiling panels (1/4″ marine ply, FRP & fair inside surface)
Insulate ceiling between frames (spray foam)
Sand Alexseal fairing compound smooth on walls
Install wiring for overhead lights
Epoxy back-side of ceiling panels and install (glue and screw to overhead frames, fiberglass joints, and fair)
Sand joints and make fillets
Sand & apply Awlquik
Sand Awlquik and apply 545 primer
Final sand 545 and spray Awlgrip topcoat in eggshell white

Since I’ll be spraying insulation to get the bathroom ready, I might as well do the rest of the boat, too. I’d like to have all of this done by July 1, when I plan to start on mechanical and get the engines finally installed. Busy, busy, busy…I need to quit my day  job! 🙂

Next up on our 1969 Chris Craft Roamer 46 Refit: Aft Stateroom Head Walls II

1969 Chris Craft Roamer 46 Refit: Insulation follow-up

A while back I wrote about the insulation plan I have in mind, with sprayed urethane foam on the overheads, under-side of the decks, and hull sides and Mountain Mist Buffalo Batt polyester nonwoven fabric applied with contact cement to the backside of all wooden panels that face the hull and overheads. The spray foam insulation has a lot of excellent properties, including a very high R-value per unit thickness of applied product, it improves structural rigidity (which is always good for cabin tops and aft decks), and it’s self-extinguishing in the event of a fire. I still haven’t decided whether to DIY the spray foam or have a pro do it, but nine rolls of Buffalo Batt arrived and are awaiting fitting and install.

Three rolls per bag

Looks kind of like fiberglass, but without the itch

1-1/2″ loft, just like the spec sheet said

That 1-1/2″ loft should yield an R-value of 3.0, which will be a vast improvement over the original approach that used no insulation on the backside of panels. The R-7 value that each inch the spray foam provides coupled with due care to avoid air leaks between the hull envelope and interior, with a dead air gap between the two types of insulation, should do a good job of keeping the conditioned air on the inside of the boat. In the Mid-Atlantic region, where winter temps recently have dropped below zero Fahrenheit (hello “global warming!”) and summer temps go into the 90s and even over 100°F on occasion, proper insulation is a very important thing. Insulating the back-side of the panels should also greatly contribute to keeping condensation in hanging lockers, drawers, cabinets and storage areas under control.

That’s the theory, anyway, and I’m sticking with it. 🙂

Next up in our 1969 Chris Craft Roamer 46 Refit: Installing the Bow Hatch…or not.

1969 Chris Craft Roamer 46 Refit: Insulation

In the spirit of jumping around from topic to topic, which is pretty much how the project has been going for the last few months, today I’m writing about insulation.

Yup. From a gantry design to laying out the floors in the aft stateroom to insulation, in three sequential posts. Makes sense, doesn’t it? 😉

Believe it or not, there’s actually some reason to the madness.

Anyway, I remember when we sold our Chris Craft Constellation 52, a mahogany hulled boat, for a Commander 42 in FRP. Oh boy…THAT winter was a lesson in thermodynamics. The old woody was so warm. So I tried my hand at insulating the Commander using a variety of materials, which yielded a variety of different ways NOT to effectively stop unwanted heat transfer. It’s all good, though, because lessons learned on my other boats are helping pave the way on our Roamer. And since the Roamer is an aluminum hulled boat, mastering the heat transfer issue will be mission critical.

I am, after all, a happily married man, and I intend to keep it that way.

So, in the category of things I definitely will not do when insulating the Roamer, we have foam board, Liquid Nails, silver tape, or any other materials sold at big box home improvement centers. Shrink wrap tape, while tenacious when used on shrink wrap, doesn’t hold for more than a few months on foam board insulation. Fiberglass batts are great for insulating… houses. On boats, fiberglass holds water and is just miserable when it inevitably fails.

Fortunately, Chris Craft’s original hull coating was in pretty good shape on our Roamer. I think it was called Bitumastic, a semi-hard tar or asphault-like substance, though I’ve heard others call it coal tar. Either way, as you can see in the pic below from when I was removing the old exhaust pipes, Chris Craft gave it a coat of silver paint to pretty it up, and it really does a terrific job of stopping condensation dead.

Good looking silver-painted Bitumatic…so long as there’s no oil around

Unfortunately, residue from oil mist of the sort that’s common in engine rooms of all but the most fastidiously kept boats pretty much dissolves this petroleum-based insulation in short order. And, really, Bitumastic (or whatever it was called) stops condensation, but it’s not going to keep the missus warm in the middle of winter. As insulation, adding more of it won’t be of any benefit.

So, here’s what I’m thinking for insulation:

All of the ceiling surfaces, including the new aluminum side decks near the helm station, the bullet proof cabin top, the underside of the side decks, and the V-berth will get an inch or two of closed cell spray foam. The thermal insulating properties of spray foam are great, and word has it nothing is better at filling voids and stopping air infiltration. Most of the two-part urethane foams have to be applied when surface temps are 70* or more to get proper expansion, which is why I’m working on getting bulkheads installed now in the middle of winter: chipping away foam insulation to make room for bulkheads sucks, and by the time the weather warms up I’ll be ready to spray the foam.

For the vertical surfaces, I haven’t decided what to do. There’s no exposed aluminum, so condensation isn’t a concern. I could foam the hull, but that would still leave me with cold air in the hull envelope coming into contact with the back-side of all my cabinets. That could cause condensation problems, plus there would be heat loss through the wooden cabinetry panels. To keep the air conditioned (i.e. warm in winter or cool in summer) interior envelope thermally isolated from the unconditioned hull envelope, I’m thinking of using spray contact cement to attach nonwoven fabric insulation to the backside of all of the wall panels and cabinet back panels that face the hull.

The table below summarizes the information I’ve pulled together on the various insulation options. It also estimates Bang for the Buck, which I define as the ratio of R-value to $/ft^2, with a higher number being better. Sorry the table looks goofy; wordpress is notorious for not being table-friendly.

Product	Width (inch)	W (ft)	L (ft)	ft^2	Price	$/ft^2	R-value	Bang for the Buck*	Notes
3m Thinsulate 1″	60	5.00	90	450	$1,018	$2.26	3.8	1.68	polyolefin
3m Thinsulate 2″	60	5.00	90	450	$1,146	$2.55	5.8	2.28	polyolefin
Thermozite	48	4.00	3	12	$12	$1.03	1.3	1.27	polyester
Mountain Mist Buffalo Batt	50	4.17	15	62.5	$28	$0.45	3.0	6.66	Nonwoven polyester fabric
Spray foam on ebay				600	$658	$1.10	6.0	5.47	DIY
Foam it Green				1200	$1,429	$1.19	6.0	5.04	DIY
Tiger Foam				600	$575	$0.96	6.0	6.26	DIY
Icynene ProSeal						$1.25	7	5.6	Pro-applied
* Bang for the Buck is the ratio of R-value to $/ft^2, with a higher number being better

3M Thinsulate is easy to handle and install, hydrophobic, and (relatively speaking) very expensive. Weaver Boatworks uses it, and reportedly so do other luxury boat and car manufacturers, though it’s marketed as acoustic insulation rather than thermal. Still, it has a fair R-value. Thinsulate fabric is a mix of polyester and polypropylene, and it’s the very fine polypropylene fibers that make Thinsulate so much thinner and lighter than other nonwoven fabrics with the same R-value. Polyester nonwoven can yield the same R-values, but it’ll be thicker and heavier. And by heavier, I mean a few ounces per square foot, which falls into the “insignificant” category on a 46′ motor yacht.

Thermozite was another product I found online that some camper enthusiasts seem to like. It uses polyester, but it’s a very thin product that’s foil lined. You might see it on the under-side of your hood, for example. It’s less than half the price per foot^2 as Thinsulate, but the R-value is so low that it really drags down the Bang for the Buck.

Which brings us to a surprising entry: Buffalo Batts, which quilters and other crafty sorts use when they need a 1.5″ lofted batt that doesn’t absorb water. It’s a nonwoven polyester fabric, but not faced like Thermozite or Thinsulate. Frankly, I have no idea if a vapor barrier facing is necessary, and the bang for the buck on this stuff is outstanding: the per-inch R-value is less than Thinsulate, but not by a huge amount. And the price is excellent. I’m leaning toward Buffalo Batts as the material I’d use on the backside of all the vertical walls.

But back to the spray foam. Tiger Foam is clearly the best bang for the buck, assuming manufacturer’s coverage data is accurate for all of the products. Tiger Foam’s product info page indicates an initial R-value of 7 and an aged R-value of 6, and the loss of aged R-value has a huge impact on Bang for the Buck. Icynene Proseal, by comparison, claims to be an advanced new formula that’s set the high bar for the industry with an aged R-value of 7, but they don’t sell DIY kits. There’s a potential cost savings of $450 for DIY vs having a pro spray Icynene Proseal. Then again, I know from spray painting that there’s a reason you pay the guy with the magic hand who can lay it on just so. Whether DIY or pro-applied, I’ll be taping and covering the whole boat to protect shiny paint and pretty wood. But, on the other hand, I do like DIY experiences, especially when they work out well.

What a conundrum. If anybody has any thoughts, experience, or suggestions, please feel free to comment.

Next up on our 1969 Chris Craft Roamer 46 Refit: Turning Mahogany Plywood Into Aft Cabin Walls