Cold molded construction?

I searched and saw the previous thread on composite construction, and wanted to revive it. I would be grateful for anyone's thoughts on cold-molded construction.

I realize the answer is, 'it depends on the quality of construction', and would especially appreciate anyone's personal experiences. With the low supply of used boats on the market, I'm debating expanding into things I hadn't previously considered. Specifically, I'm deliberating whether or not to consider a 15-ish year old cold molded boat.

I had previously thought that if done by a quality builder, longevity and maintenance could be comparable to a conventional 'fiberglass' boat. But earlier this year, there was a cold-molded boat for sale near me from Mast & Mallet. While thinking about whether or not to see it, the listing showed 'sale pending' - and then was re-listed at about 1/3 of the original asking price, saying that water intrusion had been found in the bottom. Yikes. It's now re-listed after repairs being done.

Vicem is another cold-molded boat that seems to appear in classified listings.

Any and all thoughts and experiences would be appreciated.

Thank you!

I am pretty sure a lot of the expensive, offshore fishing boat built in the Carolina area are cold molded...at least they were.


The older retired Navy guy across from me at the dock has a beautiful cold molded (could be strip planked) he build many years ago and has lived on it for years...looks better than my production trawler in so many ways.

There are many classic boat that could benefit from using an existing hull to make a mould and then begin construction of a 'new edition'.

My last boat was a cold molded lobster boat. You are right about "it depends". I think the greatest benefit of cold molding is getting a unique one-off hull shape. If the boat is shaped like every other boat, then I'm not sure I get the increased cost and effort of building it in cold molded construction. In the case of Mast and Mallet - I assume it was one of the boats built to Mike Kauffman's (sp?) design, which are somewhat original.

The idea of water in the core doesn't terrify me by itself. I would want to know what wood was used in the strip planking or molded veneers. In the case of my boat, I believe the strip planking was Atlantic yellow cedar and the veneers were Western red cedar, both highly rot resistant woods. So even if water got in, they wood would not likely rot in salt water in my lifetime.

If looking at an older boat, be aware that without a good pedigree, you should get the boat at a very good price. If is has a good pedigree, they should have some documentation on the wood used in construction.

And yes, many of the Carolina boats are still built cold molded. Although they frequently use high grade plywood rather than "tree wood". So in that case, the type of ply makes a large difference in quality of construction.

As an aside, a very experienced boat builder replied to my concerns about wood and cold molded construction with the observations: Rot requires 3 things. The right temperature, fresh water, and oxygen. If you deny it any one of those three things you won't have rot. That's why a cold molded boat kept in salt water is not likely to rot due to water intrusion. However, it is still subject to rot from fresh water (rain) getting into joints and crevices above the waterline.

The kiwis seem to have perfected cold molded boat building. I was on one years ago that I would of loved to own. I guess the statement that it depends on the builder holds as true here as on any boat. I do know that they can be really light and very strong at the same time
Hollywood

Thank you!

My concern level was raised because the (supposed) story on this particular boat is, the boat (allegedly) experienced a 'light' grounding. The owner was apparently either unaware or unconcerned with any damage. A survey found water penetration into the wood hull (beneath the fiberglass sheathing). This was supposedly repaired by grinding away affected areas, and filling with epoxy and reglassing.

I'm a big believer in vastly over-building, because sea conditions can throw things at you far beyond the range of anything 'expected'. There's no upside to a hull breach offshore.

Maybe I'm being overly paranoid, but my concerns with the explanation are,

1) if the grounding was 'light', why did such a light touch result in a breach that penetrated the sheathing enough to cause water intrusion into the wood hull? I could have a similar 'light grounding' and think everything is fine, until the sea tests it and I discover the hard way that it wasn't. Is this particular type of cold-molded construction so fragile that a 'light' grounding can cause significant problems?

2) If the grounding was more than 'light', what other hidden damage might have been caused? A careful survey and microscopic examination might reveal this, but then again, it might not.

I keep thinking back to a sea trial we did with an American Tug back in 2001. The dealer let my wife take the helm, to show her how easy it was to handle the boat. Shortly thereafter, she ran hard aground - at 15 knots. Literally nothing happened. We backed off and went on our way. I bought that boat and absolutely loved it for the years we owned it. There were no issues or any signs that the solid glass hull (about an inch thick) had ever hit anything.

Grounding damage depends on a lot of things....bottom composition, impeded objects, slope, duration, wave conditions, actions by skipper, etc...etc...

I think you need to be careful with the term cold molded. Modern wood/epoxy builds that are completely different beasts from the cold molded boats of my youth.

Not trying to be pedantic, but it matters. There are a lot of variations.

Also I've seen more than a few cases of GRP boats with water intrusion into coring.

Jeff F said:

I think you need to be careful with the term cold molded. Modern wood/epoxy builds that are completely different beasts from the cold molded boats of my youth.

Not trying to be pedantic, but it matters. There are a lot of variations.

Also I've seen more than a few cases of GRP boats with water intrusion into coring.

Click to expand...

Curious...what differences other than glues?....and maybe greater use of plywood?

psneeld said:

Curious...what differences other than glues?....and maybe greater use of plywood?

Click to expand...

Not an expert. But builders l'm passingly familiar with like Covey Island Boats in Nova Scotia probably would be probably be horrified if someone referred to their boats as cold molded. There are a number of yards in Maine that turn out beautiful - and very expensive - wood/epoxy yachts.

My point was that you have to get into pretty specific details about construction to talk about maintenance or structural decay concerns. And most wooden yachts built within the last 20-30 years bear little resemblance to their predecessors it terms of how they're put together.

I was paying attention when the Gougeon brothers who founded the WEST system were doing some really innovative things with sailboats and iceboats in the 1980s. My sense has been that they sort of revolutionized wood yacht construction, at least in North America. They developed some really innovative and high tech wood/epoxy structures, and payed equal attention to both components.

Or maybe it's me being pedantic. It looks like you guys all agree on what a cold molded boat is, so I'll shut up and learn...

A cold molded hull would be a great choice for a hull that needed to stay light.

Today epoxy takes much of the risk out as it spans gaps the old resourconal and other glues could not.

For a rock crusher single skin GRP over a male plug , would be first choice.

Look at Covey Island Boats in Lunenburg,NS for some beautifully built Cold molded boats

Wood epoxy refers to materials. Most modern cold-molded boats are made with those materials but not all boats made with wood and epoxy are "cold-molded".

My working definition: Cold-molding consists of multiple layers of thin veneers of wood set in epoxy over closely set frames. Each layer is at a 45* angle to the previous layer. The end product is essentially like a plywood, but in the shape of your boat. It's VERY strong and VERY light. It's highly resistant to rot. The biggest drawback is the cost and time to lay and fair each layer. I've seen this with 3 layers being considered the minimum.

Strip planked boats of the wood/epoxy type are square strips of wood, edge glued to one another over temporary frames spaced relatively far apart. There can be one or more layers of strip planking. This is a faster method and is lower cost. But water intrusion can run the length of the strip and can cause splitting down the length.

For hard chine and non-developable surfaces, plywood can be put to good use. This is a part of many of the NC sport fishing boats as well as "stitch and glue" construction. I've got some pics of those under construction somewhere. This is a good and cost effective technique, but requires a hull shape that can accommodate flat materials (i.e. a non-developable surface). I don't know how the construction cost stacks up - but the sportfishing boats I saw in NC under construction sold for well over a Million bucks.

For a curvaceous shape (my favorite), a good compromise is strip planked, followed by one or two layers of veneer (topped off with fiberglass set in epoxy). Once the veneers are set, they resist any lengthwise splitting of the strip planked layer. Its cost is somewhere between strip planked only and cold-molded only. They only way to know this is how a boat is built is to specifically ask about the construction method.

All these (and probably others) can be accurately described as "wood epoxy" but not all are cold-molded.

My last boat was one layer of strip planking followed by two layers of red cedar veneers and only layer of fiberglass, all set in epoxy. The deck was plywood with Dynel set in epoxy. In the end, the whole boat was a single structure, stiff, very watertight, and light. At 5,500 lbs, she was around 1500 lbs lighter than the same boat that was built in traditional wood.

I had a composite boat that was built in 1961. It was a Sumnercraft built in Amitivile NY. A 29’ diesel cruiser powered by a Sabre 120 engine that is based on the same Ford engine that Lehman engines used.

The hull was built up first as a strip built boat, up side down and planked w cedar. The “forms” (kinda like bulkheads) were placed crossways to form the shape of the hull. Then it was overlayed w polyester resin and FG cloth.
Then the hull was turned right side up. The forms were removed and the interior surface of the hull was overlayed.

My description above may be somewhat inaccurate. It’s just from memory except for the photo below.

I bought the Willard and for a time had both boats. This was just before we moved to Alaska. Soon I had to sell one boat and move north. I really wanted to keep the Sumnercraft but I was wary of having a composite boat in Alaska. I tried and tried to trust the hull but in the end I kept the Willard boat .. that was well suited to Alaska.

The Sumercraft showed no signs of failing in any way but I thought water will at some time reach the structural wood that was nowhere visible. The boat had already given good service for about 40 years. I was kind-of embarrassed for my inability to accept the mostly obvious. I loved the boat. It was capable of running at speeds very very few other boats could gracefully go. Nine to about 14 knots in this size boat.

The Sumnercraft didn’t leak anywhere that I could see. But I was afraid of having to repair it in Alaska. But If I had to choose again and wasn’t going to Alaska I’d choose the composite boat.

We came really really close to buying the 67 Vicem at NPB boat show, due to the CV it lingered on the market far too long and did not sell well. Gorgeous boat, at a bargain I think. I too had questions about cold molded. Their interiors are incredible. Been waiting for the other shoe to drop, but instead the drum beat is getting faster and louder, time getting shorter.

https://youtu.be/gIewtyQd9pM


https://youtu.be/jtYPUdfbo5Q

If resale is a concern then be very cautious. If you lived here in Florida then forget about it unless you're paying 1/5 the asking and consider it completely sunk cost. Maybe in the PNW or northern Europe it might be more accepted. There's a nice trawler for sale here and the broker keeps hammering me about it, but I'm not paying six figures for a vessel that no matter how you look at it, is "wood cored below the waterline" in essence.

Mako said:

If resale is a concern then be very cautious. If you lived here in Florida then forget about it unless you're paying 1/5 the asking and consider it completely sunk cost. Maybe in the PNW or northern Europe it might be more accepted. There's a nice trawler for sale here and the broker keeps hammering me about it, but I'm not paying six figures for a vessel that no matter how you look at it, is "wood cored below the waterline" in essence.

Click to expand...

Of course they are going to try and market it to their advantage, Vicem claims CM is lighter, stronger, more durable. They have a lot of these boats out here, has anyone heard of or seen issues with them? That first video shows how they build a CM boat. I think someone said they are doing more in FG now.

Bkay is giving you some really good textbook answers on this.

My particular boat:
My working definition: Cold-molding consists of multiple layers of thin veneers of wood set in epoxy over closely set frames. Each layer is at a 45* angle to the previous layer. The end product is essentially like a plywood, but in the shape of your boat. It's VERY strong and VERY light. It's highly resistant to rot. The biggest drawback is the cost and time to lay and fair each layer. I've seen this with 3 layers being considered the minimum.

The builder utilized six layers of 3/16 thick Western red cedar, with epoxy on each side with a resulting 1 5/8 thick hull form.

The exterior has fiberglass roving for abrasion resistance etc.


After owning this boat for almost 20 years, I am pleased today as I was on day one with the construction technique.


As has been previously mentioned the light weight of the hall is a definite Factor. If my boat weighed another 10,000 pounds it would not Bob around like a cork in big seas.

I believe the op is asking more about durability or longevity, and agree wholeheartedly that this completely depends on who built the boat.

Without doing destructive testing sometimes that's hard to figure out without the backstory on construction.

Also would mention that it's only typically the hull that is cold molded so the cabin and superstructure will need to be protected from the rain. Just make sure you can cover the boat in the off season weather in Moorage or boathouse or in a shed somewhere.


Find a surveyor who understands the technique

A big hassle today is finding marine grade plywood that can be udes.

In the mid 1960's I had a 45 ft boat built in then British Honduras (now Belize).

The Thames Ply was African Mahogany 5/16 thick was 5 ply so very stiff , and the factory shipped it CIF (carige, insurance & freight) with the final surface not finished sanded to save time.

The pressure for the layup was Monel staples that did not have to be removed after the glue dried.

Dynel in epoxy was the outer surface covering , was a great combination, the boat
was a success. 6,000 hours of superb wood working was $4,500US.

Clearly it depends on how well the process is executed. But Cold Molded boats as defined above with thin layers of plywood crisscrossed over a "mold" then glassed produce some of the lightest and strongest hulls going, with significant improvement in performance, weight, and speed over similar FG hulls.

Top tier Carolina sport fishing boats like Jarrett Bay, Bayliss, and Spencer build Cold Molded works of art that are highly coveted and perform significantly better in terms of speed and economy over similar sized FG boats from well regarded manufacturers like Viking and Hatteras.

In short, to me, Cold molded is a high end, high performance construction technique, that if done well is superior to FG but takes significant skill and expertise, not just to build, but to maintain, when it comes to drilling holes and installation of ancillary equipment by subsequent owners...

I remember an argument over I heard in a cafe in Juneau Alaska.

One man who owned a Rienell (sp?) boat and the other a Bayliner. The boats were exactly the same except for the FG layup and resulting weight difference .. think chopper gun. The two boats had just arrived via barge and their paperwork included the weight of each boat. The Bayliner was considerably lighter.

The Rienell boat owner was of a mind that heavy was better .. period. The kind of mentality that would put a big Navy anchor on the light plywood boat.
The other owner w the Bayliner knew light was better within reason.

They yelled w great enthusiasm to support their philosophy and boat brand. I was naive to a degree then and considered every pound “extra” as sinful and stupid. Could hardly believe the Rienell owner was spewing such stupidity. I’ve come a long way in the last 50 years and realize there is some advantages to more mass in certain things. But generally speaking boats are better off weighing less.

And cold molded boats offer the highest level of performance possible short of almost unimaginable extremes.

But most here on TF are a bit closer to “it’s hard to get a rec trawler too heavy”. So I don’t think many here will be inclined to pay extra money for light construction in boats. Or want to take even small chances on unusual construction methods or materials or both to get a lighter boat. However me being of the lighter is better opinion, sometimes to extremes has for the last 16yrs owned a 30’ boat w 25% of it’s weight in ballast says heavy has some very appealing advantages. So weight isn’t as big of a sin as I had thought. But one would be hard pressed to find a better way to more speed .. generally speaking .. and there are many many skippers here keenly interested in more speed. So would a lightly constructed trawler be the ideal trawler? Perhaps. But more likely just 10% lighter would please a lot of trawler people. My opinion still isn’t that of most in that I’d rather have a FD trawler or a light cruiser but less so boats in-between. However many more should consider this element of quality in a boat before buying .. new or old. If you buy a heavy Huey it will be mostly impossible to make it light. While adding weight to a light boat will probably just make a bad boat. So when you buy is the golden hour.

I recently sold my Vicem 58' due to my health issues. It was a cold-mold model from 2005.

The state registration considered the hull plastic/composite - not wood.

Storage, cleaning, motoring - I did everything the same as all my FRP boats since 1981. There is plenty of wood in a Vicem, but as mentioned the layup and use of West System epoxies makes the boat every bit as light and even more resistant to puncture than the super expensive MJM carbon/ kevlar boats.

The hull stiffness and strength means the boat does not twist in big seas or heading against chop. No twisting means that a 15 year old boat has every door, hinge, hatch, locker, bearing etc all in the same place as it was when newly built. Very quiet too.

The low weight/ length means the bow will lift and the boat can cut through and surf over chop. I found I could accelerate and completely smooth out the ride when there was a chop. The boat was still the heaviest vessel I ever owned, and the most comfortable boat I ever drove or lived aboard.

The Vicems don't seem to be very well known here in the USA. People always came over to us to chat about our "Hinckley" and had never considered the superb design and craftsmanship of Turkish builders. Nordhavn is now building their 41' in Turkey, and many aluminum FPB types are built there. The factory also readily answered my emails about parts and build questions - this on a 15 year old boat!

Vicem will build FRP boats since they are much cheaper to fabricate.

If you can get a Vicem you'll have a safe and sea-kindly vessel. I think the Vicems are highly undervalued. The interior woodwork and detail, the hardware, and the hull are 100% superior to Palm Beach or new Grand Banks.

just my opinion, but I owned one for a while.
Richard
ex-Vicem 58 Classic
New Haven, CT

My first boat is a 40' cold molded Kiwi sloop. It was built and launched in 1982. I am the third owner. It has taken me more than 30,000+ ocean miles, including twice across the Tasman, and once across the southern Ocean. It is double diagonal, and was built to a high NZ standard by a legendary Kiwi designer and builder. It is light, strong and fast. And beautiful to look at and to sail, in all conditions. The bilges still look llike high grade furniture.
Like a boat with a cored deck or hull, you have to pay attention. The market for them is funny, because those who don't know write them off, and those who do, seek them out.
If the OP is serious, find a survey who really understands the method of construction.

Cold Molded Boat

I have an over 20 year old cold molded downeast type hull. It is a one off Blackhorse 32, from which molds were made for later production fiberglass hulls. It was built with 3/4' cedar strips and two and in some areas three layers of Okume plywood on the outside and finished with glass cloth.

Inner hull was well covered with glass cloth. My understanding is that the key to all of the construction is the use of epoxy on and between every surface .

It weighs 3000 Lbs less than the sister glass boat, according to the builder. I have not been able to confirm that.

My biggest concern has been keeping the bilge as dry as possible. Evolution shaft keeps seawater out, but it is an express and occasionally rain water will get in.

I have been over it with a moisture meter many times, but I have never really felt the meters to be 100% accurate.

etype38 said:

I have an over 20 year old cold molded downeast type hull. It is a one off Blackhorse 32, from which molds were made for later production fiberglass hulls. It was built with 3/4' cedar strips and two and in some areas three layers of Okume plywood on the outside and finished with glass cloth.

Inner hull was well covered with glass cloth. My understanding is that the key to all of the construction is the use of epoxy on and between every surface .

It weighs 3000 Lbs less than the sister glass boat, according to the builder. I have not been able to confirm that.

My biggest concern has been keeping the bilge as dry as possible. Evolution shaft keeps seawater out, but it is an express and occasionally rain water will get in.

I have been over it with a moisture meter many times, but I have never really felt the meters to be 100% accurate.

Click to expand...

Just beautiful!

etype38 said:

I have an over 20 year old cold molded downeast type hull. It is a one off Blackhorse 32, from which molds were made for later production fiberglass hulls. It was built with 3/4' cedar strips and two and in some areas three layers of Okume plywood on the outside and finished with glass cloth.

Inner hull was well covered with glass cloth. My understanding is that the key to all of the construction is the use of epoxy on and between every surface .

It weighs 3000 Lbs less than the sister glass boat, according to the builder. I have not been able to confirm that.

My biggest concern has been keeping the bilge as dry as possible. Evolution shaft keeps seawater out, but it is an express and occasionally rain water will get in.

I have been over it with a moisture meter many times, but I have never really felt the meters to be 100% accurate.

Click to expand...

Wow,
That's a amazingly beautiful boat, what power does it have and what speed and fuel burn.
Thanks
Hollywood

It has a Yanmar 350 and cruises at 19 kts with 23 at WOT

I had a cold molded boat. About 50 years ago more or less. It was a 20 ft day sailor that lived in the water. It had age on it when I bought it, and more when I sold it. The hull was still in great shape. Better than the wood spars.

With reference to "Marine" plywood, today, for wood construction above the waterline, exterior grade baltic birch is available. It is constructed of much thinner layers which produce rigid and strong panels. I use this material to build interior walls, cabinets, etc. In my repair shop, nothing goes into a boat until coated with at least one layer of fiberglass and epoxy. This eliminates problems caused by condensation and high humidity. All that being said, we would never use ANY wood below the waterline, inside or out and that being a conservative statement. One BIG reason that you can't find Marine plywood is that few people even want it anymore, because it is wood. Would I even consider building another boat using anything other than fiberglass/epoxy, NEVER. After 50 years of repairing boats, except for impact damage, 95% of the needed repairs have been to find and replace the wood that was used that somehow had water intrusion. True, rain water causes rot damage, but ALL water intrusion causes failure of the wood whether it be structural strength, delamination, leaks, etc.
This week we chased a leak caused by a screw that was used to attach trim tabs. The screw broke off, allowing water to enter. But, this screw went thru the transom and into the trailing edge of a wood stringer. The stringer was encased in fiberglass, so the water had nowhere to go except forward thru the stringer. It exited 25' forward thru a cross hole drilled between stringers in the bilge. Obviously, the stringer core was water soaked and it allowed enough water to enter to trip the main bilge pump every hour or so. The stringer appeared sturdy everywhere that it was inspected. The customer chose to have the hole repaired rather than gut the boat and replace the stringer. Again, the point of this whole reply is that in my opinion, wood should be avoided at all costs in boat construction. Eventually, it will suck up water, and cost someone many times the savings of using it in the first place. Lastly, termite damage is easy to chase down and fix in a cabinet. When they get into structural wood, including cored materials, replacement is the only fix, if even possible.