A bumpy night, indeed! Clearly Bette Davis wasn’t talking about boats here (we all know what she was talking about). But talking, writing and selling boats is what I do. So this week The Fog Warning turns to the timely subject of hull construction. Specifically, an analysis of cold molded vs. fiberglass construction methods.
Let’s start with a video. Here’s a [cold molded] Vicem 72 doing 26 knots through 7 foot waves (and 30 knot winds), somewhere off the Chesapeake. Watch (and try to imagine the feel) as the boat comes off each wave, burying its substantial bow:
Wait, I say! Where’s the Archimedean (spellcheck assures me this is a real word) crash of 60,000 pounds of boat suddenly displacing 250,000 pounds of water? Where’s that teeth and kidney-rattling thump? And how does that laptop just sit there, unsecured, on the nav table? These questions all have the same answer: cold molded construction.
Here’s another example, bringing a [cold molded] Vicem 78 from Fort Lauderdale to Miami (yah, that’s me dating myself with the Victory at Sea comment). It’s deceiving, as this is a bigger, heavier boat than the 72, but these are 8 footers, with a few 9’s thrown in for effect:
To quote Aretha Franklin, my eternal Queen of Soul:
Steady enough that a helicopter could have landed on our deck, first attempt.
As an aside, that sort of ride can lull you into a bit of ill-advised complacency. When we reached Miami we had to plan a starboard turn into Government Cut. We belatedly appreciated how rough those conditions were, and how critical the timing of that turn had to be (those were not waves we wanted to stay broadside to for very long). But we throttled back, cruised along until we found a longer fetch, and did a fast power turn right into the channel. Peace of cake.
Got it? Cold molded construction is all about the ride.
In my hundreds of hours of running cold molded boats, all over the world in all sorts of conditions, I’ve experienced very few instances of pounding. Here’s an eye-opening and stomach-churning clip about pounding, offered for definitional purposes only:
The rare instance I had came when dodging a fierce lightening storm off Croatia, running too fast for the conditions. (Lightening strikes were hitting the water randomly, and I’d do it exactly that way again, all things considered.)
Notwithstanding that day (it’s become a great scene in my novel), if you blindfolded me aboard a test boat I could tell you with near 100% certainty if she was of fiberglass or cold molded construction. So too could most of my owners and captains. When the issue is ride, cold molded is better, every time. Why? Because the hulls are designed to flex, to squeeze themselves through difficult waters rather than hammer themselves through. It’s a thrilling feeling.
So then, what exactly is cold molded construction? Personally, I prefer the term “Composite Construction.” But I recognize that can be confusing to many (“Wait Dave, I thought fiberglass is composite construction?”). So let’s stick with “cold molded” for today.
It’s lunchtime here in the snowy Hamptons, and I’m writing in front of my fireplace, thinking about sandwiches. Which, whether cold molded or fiberglass, is exactly what a modern hull is. In fiberglass hulls the “meat” that makes up the inner layer is hi-tech foam. The outer layers (the bread, if you will) are fiberglass cloth, saturated in resin or epoxy. When everything cures, you end up with a bonded sandwich, much lighter and stronger than a hull built of solid fiberglass.
With cold molded, the “meat” is thin strips of solid mahogany, four or five layers’ thick, saturated in epoxy. Then, as above, the outer layers (inside and out) are fiberglass cloth. The strength comes largely from the way the the mahogany layers run in alternating directions, like this:
This method works brilliantly up to about 120 feet. At mega yacht size, boats tend to twist laterally as they rock and roll, and every component must be designed and built to handle that movement. It’s easier to accommodate that twisting with fiberglass, steel and aluminum construction. But make no mistake, very large yachts have been built with these mahogany cores:
[This is a good place to note that Reliant Yachts and SuMarine (our builder in Turkey) has the expertise and experience to design and build everything up to and including mega yachts — from expedition yachts to the fastest of the go-fasts — in fiberglass, steel and aluminum as well. Call me for the details.]
So a sandwich is a sandwich. But, as we’ve seen, cold molded gives you that great ride. It’s also:
- Lighter (which means you can go faster with the same engines;
- Stronger, both torsionally and for impact-resistance;
- Quieter (nothing beats the natural sound-deadening qualities of wood);
- More insulated against heat and cold;
- Doesn’t need a gelcoat, so gelcoat blisters are moot;
- Cheaper (there’s no need to build an expensive mold) if your skilled labor costs are low; and,
- It gives you that romantic (if not technically accurate) thrill of connecting yourself to thousands of years of navigating wooden boats. That romance is easier to show than to describe:
The flip side, you may ask? I’ve spent all morning trying to come up with the disadvantages of cold molded construction, and I’ve come up with only one: The comparative lack of familiarity with the technology, making re-sale more challenging. That’s where….
Warning: Self Serving Statement Ahead
….an informed broker can be your best friend.
Which sandwich would you like? At Reliant Yachts, each of our models is available in either cold molded or fiberglass.
Fiberglass costs more, of course (remember that mold?). But if — like Bette Davis — bumpy nights turn you on, we’re happy to build it exactly your way. Please feel free to call me (or see me aboard our Commuter 40 at the Palm Beach Show next week) for the details on any particular boat.
So that’s it for this week. Thanks, as always, for indulging me. And stay tuned for the next edition of The Fog Warning, where I talk about presidential yachts —
— and, after much urging from you, my loyal clients, I begin a four-part series on the history of downeast boats. Hmmm, someone should write such a book, no?
The season approaches, so enjoy!
Big Wave Dave
PS: I must leave you with a small gift: The original Rock Steady!
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