First Deadline Missed
Our newly certified BS1088 Meranti hull-planking, clamped in place by 200+ screws and fender washers
On my January 1st post Affirmations and Aspirations, I said I hoped that by the end of January we would have the lower hulls glassed, faired, and turned, but that’s not to be.
As mentioned in my Making a Living in the Wake of the Pelican Disaster, we had to jump through some extra hoops to get our plywood selection signed-off on by USCG Marine Safey Center and that set us back a couple of weeks.
We spent those weeks making rudders and crossbeams, but since those aren’t parts we planned to work on until April, it’s hard to say how far ahead or behind we are at this point.
Either way, the boat is now in two distinct sections, which makes figuring out how to deploy more hands and backs easier, which means the Montauk Catamaran Company is hiring again – 2-4 more workers to get things moving along.
It’s probably too early to expect Karl Rove to hold himself accountable, or even give an update (he’s a conservative, and conservatives believe in accountability, don’t you know), but I expect at least a few of his chickens will have come home to roost by the time Mon Tiki is launched.
Also unknown is how many jobs Karl Rove has created. But I shouldn’t be so smug. I have a car commute for the first time in my life, and not a short one. That blunts the edges of my patriotic pride.
What additional information or tests did the USCG want to approve the plywood?Report
We had to send a sample of our plywood to an ASTM certified lab and have a battery of tests conducted on it. It came back about 65% stronger than required to meet the USCG spec, and the USCG spec itself includes a generous safety margin. MON TIKI is going to be one very strong boat!Report
If you’re the very first builder to get through this certification process, you should submit your story somewhere others could benefit from it.Report
Yes, we should and we are. You guys are my beta readers. 😉Report
I’ve been dinking with the design of my houseboat in a desultory way. Every pontoon houseboat I’ve ever seen has been a marvel of both ugliness and unseaworthiness. Mine won’t be.
I’m learning how to do expanding foam wall construction onto a draped form, making it possible to have an insulated air conditioned space, like a fridge itself. Thick wall though, unavoidably Roger Dean-ish, there are no corners, it’s all curves and chicken wire on forged steel rods.Report
I’m learning how to do expanding foam wall construction… there are no corners,
Perfect for Wisconsin!
And we’ll finally see that house of foam
…It’s our dream vacation in the DellsReport
Won’t be build in Wisconsin. I’m trying to confine the keels of the standoff pontoon skids to the dimensions of a standard lowboy trailer: that’s my constraining dimension. Neither love nor money could convince me to spend so much as a cent in the Wisconsin Dells.
I don’t do dream vacations. I don’t work more than 10 months a year anyway, screws up my taxes. I put the sharp point of my compass point down in a port town and swing the pencil point out a day’s voyage out, looking for somewhere to put in of nights. If I play my cards right, anywhere I can get AT&T to give me a data channel, I’m in business.Report
I’m trying to confine the keels of the standoff pontoon skids to the dimensions of a standard lowboy trailer:
Sounds pretty constraining for a house boat. Love the overall idea, though.Report
That’s an understatement, heh. Clearly the boat is going to be wider than the truck bed. A flat bottomed boat is a lot easier to work with but if I do it right, I can put in some system to adapt it to a standard truck trailer.
Louisiana waters feature many submerged snags: if I go the pontoon route, I’m going to fill them with foam and armor the bottom with the aforementioned skids, taking guidance from the little crawfish boats that roar around in swamps, running over submerged logs and such with considerable aplomb.Report
Are those screw/washer combinations a permanent part of the boat now, or do they unscrew before the fiberglass epoxy stuff goes on?Report
The screws/washers are performing a clamping function, and are removed prior to the exterior being skinned in glass and epoxy. That’s what we did today for the port hull: took out all the screws and started filling and fairing in preparation for glassing.Report
So how did you connect the skin of the hull to the framing? Or is it floating?Report
Ahhh. GLUE! Is that right?Report
Glue is the correct answer.
The boat has very few fasteners or other metal components. She’s glued together using epoxy and additives that give different properties. By volume 8 parts mixed epoxy, 8 parts fumed silica, and 1 part milled glass fibers makes a good glue: stays were you put it, fills gaps, and is very strong.
There are also a lot of structural fillets: coved beads of epoxy and fillers that go into corners where bulkheads and side panels meet. These at a lot of strength/stiffness to the structure.Report
Yes, of course. That makes perfect sense. For some reason I was thinking fasteners would be necessary, but my own experience has taught me that isn’t so. It just took me a while to remember that.Report
Total boat idiot question: what’s the lifetime of a skin?
And how do you extend/replace it? Do you have to take the old one off, or just…Report
The safest answer is “It depends.” Some data points:
My friend Bob built a Tiki 31 using exterior-grade plywood. 30 years later, the boat is still in service somewhere in France. For MON TIKI we’re using Bob’s epoxy application methods, but using marine-grade plywood from a more rot-resistant species.
At the other end of the scale, I’ve build a handful of semi-disposable dories and dinks, using the cheapest materials and treating them very poorly. They seem to last about 5-10 years depending on use and luck.
The two enemies are rot and sunlight.
Rot is an internal enemy promoted by fresh water (leaks through the deck) and lack of air circullation. Good design and keeping fresh water out is the best preventative of rot.
Sunlight is bad because of the UV component. UV breaks down epoxy, which exposees teh wood. A well-maintained paint job will protect epoxy from UV.
Damage to a plywood skinned boat is easy to fix. Cut out the damage; use the hole as a template for the patch; back up the patch with glass and/or plywood; fair and paint the exterior.
BTW, each hull of MON TIKI has five (5) separate water-right compartments. I won’t call her unsinkable, but she’s very well protected from sinking. If her skin was damaged, we could beach her at high tide and probably get the repair done before the next high tide.
Report
If her skin was damaged, we could beach her at high tide and probably get the repair done before the next high tide.
Heh, that reminds me of the time I was using a folding canoe (skin stretched over a collapsible frame of aluminum poles) on the John Day River in Oregon. 5 miles down river (with 78 miles to go before the next road) I noticed the boat was filling with water. A quick examination revealed that a shockcord holding one of the sets of aluminum framing poles together had broken, and where two poles came together (butt jointed, not a male/female connection) they had already rubbed a hole through the skin of the boat. Oddly, when I rented the boat the day before, the shop had forgotten to give me the patch kit, but were still there after hours when I realized and rushed back. So we taped up the pole joint with duct tape, then sewed a patch on the bottom of the boat by the light of the moon and a campfire.
Pain in the ass, but a great memory.Report
Comment lost in the database crash earlier today:
So does the ply need to breathe? Can you bypass the possibility of a rot problem by epoxying the interior? I imagine there are cost implicationsReport
The boat is “mumified” in epoxy inside and out, and as long as that stays intact, the wood undernegth is safe.
The trouble comes when the coating is breeched, so care must be taken with the mounting of hardware, etc.
Another nice thing about plywood is that worms hate the glue. Even if they get into the first layer, via a ding or damage or what not, the first glue line will stop them. So what you end up with is a material with the strength/weight ratio comparible to steel, but workable with handtools, and resistant to worm damage.
BTW, my friend Bob is a big advocate of carbon fiber for much teh same reasons: very strong, but fabricatable with ordinary tools. Add Dyneema for rigging and you can make a very strong boat with little more than a skilsaw, squeegee and knitting needles.Report
Can you buy dimensional and sheet carbon fiber? Where?Report