Why Cement Ships Were A Terrible Idea 

I knew a guy that built a ferrocement sailboat. I sailed on it many times. It was very stable, and durable. Last I heard, the boat was looking for an owner, and still in pretty good shape, considering that it was decades old.

And repairs are easy to do ! I ve seen a few around marinas in the UK and Spain.

I saw a cement sailboat in Fajardo, Puerto Rico, looked like like it was doing well then.

Was on one last year (unfortunately only in the harbor) and the owner told me that the durability is because of the hull shape. Up to a certain wind speed and wave height, which is beyond what he liked to travel in, the whole hull is under compressive stress.

@@Andyswolftraxx I’ve been there!!

Ferrocement is a composite reinforced concrete material, originating from marine construction, in which concrete is applied in a very thin layer to densely spaced small diameter reinforcement. ‘Ferrocement is a form of reinforced concrete in the sense of the grouping of the terms ‘reinforced’ and ‘concrete.’ It differs, however, from reinforced concrete by the manner in which the reinforcement is distributed in the matrix. The general arrangement of closely spaced continuous reinforcement converts the matrix into a composite material unlike conventional reinforced concrete. Because of the closer spacing (of the order of 1 to 2 inches) and the thin sections. The nature of the reinforcement is such that hardly any formwork is required to form complicated shapes.’ --Ferrocement-Materials and Applications. ACI Special Publication SP-61, Detroit, American Concrete Institute, 1979. The definition of the ACI Committee on Ferrocement is ‘Ferrocement is a type of thin wall reinforced concrete construction, where usually a hydraulic cement is reinforced with layers of continuous and relatively small diameter mesh. Mesh may be made of metallic materials or other suitable materials.’ Ferrocement was the material of choice for Nervi, and he speaks of the material in these terms. ‘The fundamental idea behind the new reinforced concrete material Ferro-cemento is the well known and elementary fact that concrete can stand large strains in the neighborhood of the reinforcement, and that the magnitude of the strains depends on the distribution and subdivision of the reinforcement throughout the mass of concrete. With this principle as a starting point, I asked myself what would be the behavior of thin slabs in which the proportion and subdivision of the reinforcement were increased to a maximum by surrounding layers of find steel mesh, one on top of the other, with cement mortar. The square mesh was of the standard type on which plaster is sprayed in the construction of ceilings, and was made out of ductile steel wires 0.02 in. in diameter, set 0.4 in. apart. It weighed 0.15 to 0.35 psf. The mortar was made of 0.6 to 0.75 lb. of cement to the cubic foot of good quality sand [probably meant to be …to the pound of good quality sand.]. The slabs were very thin, but extremely flexible, elastic and strong. Later on, in order to increase the thickness and the strength of the slabs without using more than 10 or 12 layers of mesh, I tried inserting one or more layers of steel bars 0.25 to 0.4 in. in diameter between the middle layers of mesh, thus attaining thicknesses of 2.5 to 4 in. It must be noted that the thickness of all slabs was only slightly greater than the thickness of the package of mesh, the additional thickness being that of the mortar required to cover the two outslde layers of mesh. The material thus created did not behave like regular concrete, but presented all the mechanical characteristics of a homogeneous material. Experiments with the new material demonstrated immediately its most important and fruitful properties: it could withstand great strains without formation of cracks in the cement mortar, as a result of the subdivision of reinforcement, and it eliminated forms, because the mortar could be applied directly to the mesh, which would act as lath to retain it. # Intersecting steel rebars that form right angles forming a double-shell reinforcement 1 inch deep below the concrete top surface and 1 inch above the conrete bottom surface. With post tensioning used in bridges that has 2 supporting beam and post supports, then on a slab it should be INTERSECTING LENGHTWISE AND CROSSWISE POST TENSIONING for the supporting beam and post supports are replaced by the EDGES of the slab at the FRONT AND BACK AND LEFT SIDE AND RIGHT SIDE. The the post tensioning should be Intersecting post-tensioning cables that form right angles from the front to the back, and from the right side to the left side. But personally I prefer a double-shell of intersecting steel rebars that form right angles like a square grid pattern. And combine it with double twisted pre-anodized galvanized steel fibers. Forming a very dense hybrid steel rebar-steel fiber reinforced concrete.

most modern ships have sealed compartments, but that is so even if the ship floods it will still have enough displacement to stay afloat.

@@kenbrown2808 What a Titanic idea! 😉

I hope you make more videos. Hopefully about subjects that you actually know something about, and/or have done more substantial, unbiased reasearch on. This one was, well.... cringe-worthy.

Is that a slander against the TITANIC 1912 sinking ⁉️

He's not a good presenter. Their most extensive and dramatic life expectancy was 4(!!) Years. Most ships - even liberty ships - can last decades with repair. At least longer than that. On top on that you can't really tell if you have normal cracks or if the highly corrosive sea water has started to break your ship. That alone is killer. With steel, at least if you see a crack you know it's a problem. With concrete they're expected. This is the plastic cup of ship building. It has a lot of complex issues around them and are not sustainable, or even practical. They typically end up more expensive too. With cups people are happy to overlook it, but shipyards are a little more picky. Sailors hater them, and to be blunt, that's as much a reason as any. They're the experts.

@@RobinTheBot in a war four years is plenty, before airborne radar got functional, the U-boats were sinking a lot of shipping

Like wood construction, the cost of labour is the drawback.

t wasn't a terrible idea, it's just a clickbait title.

@@RobinTheBot i could imagine that with todays high developed concrete, you could rise that by alot of years of service. the biggest problem i see is, that with huge waves, cracks could appear in the hull. imo a very cheap alternative for calm waters

Surprised these weren't mentioned honestly

Judging from satellite photos, there seem to be nine of them. Or are they not all concrete?

There’s what’s left of one off of cape may itself as well

In Craig Alaska there was a concrete hulled former 58 foot seiner stripped but still afloat and tied up in a slip… about 20 years ago

Who was the bird brain who first conceived the idea of concrete ships anyway? There's one of them at the end of Cape May, New Jersey, that can still be seen today, jutting up from the waves. Why didn't the idea of using straw instead suggest itself to his mind? It would have been cheaper anyway, before white coated, cooler and wiser heads had prevailed.

Problem is that they crack in a million places. That said, a naval architect named Jay Benford came up with a boatload (Pun intended) of designs for power and sail boats. I was actually seriously looking at building one of them, a 32 foot motor sailor. That was back in the 70s.

@@sabrekai8706 I understood one of ferocrete's advantages was any cracking or damage remained localized rather than unzipping seams or welds or buckling frames

@@zopEnglandzip It does but where the problem comes in, especially up here in the North, is when water gets into the cracks. It corrodes the steel inside, be it chicken wire or welded mess. Rust expands, causes the concrete to break up further. You see it all round here, especially on bridges that are not maintained regularly. Benford went away from chicken wire to welded mesh, a much better system. But unless the mesh is epoxy coated, it will corrode. The concrete needs a sealer coat on it regularly to prevent seepage. An example more familiar to American readers would be the photos taken of the underground parking lot of the condo that collapsed in Florida a year ago. Concrete spalling off as the rebar rusted. It's even worse in a salt water environment.

@@sabrekai8706 ok yes the microcracking not damage. I'd expect the poly fibres to be popular with people still building with this technique but from everyone I've ever spoken to, in the eyes of the insurance companies the irreparable bad reputation was earned in the 1970's boom days of ammeter boatbuilding which amuses me as my only regular contact with buoyant cement structures is the boat yard's fibre cement floating dock which the insurance company paid for following it's plastic predecessors demise in a fire. Be an interesting field to keep an eye on over the next few years, obviously graphine was somewhat oversold but as a concrete reinforcement it's finding it's first commercial success. Did your boatbuilding aspirations ever come to fruit? Michael Verney's "complete book of ammeter boat building" lead to several canoes and dinghys but I'll never build anything bigger as I'd find fitting out too tedious.

@@sabrekai8706 Again though, the persistence of the wreck proves its durability even in salt water. This is a world war 1 wreck where many world war 2 era wrecks, made of steel, have broken up completely.

Check out The History Guy, He tells us of history that as he says deserves to be remembered.

We used to go to Sunset beach every time we went to Cape May. During the summer months every day at sunset they would retire the flag with taps and or the national anthem played. Always a sight to see.

What about fiberglass?

@@TheWaynester101 Fiberglass (polyester laminated with glass fibers) was thought to be a very good material for building boats, until the first boats suffered from osmosis. Up to now nothing like this is known about ferrocement.

The Cadillac of the Sea

Do you have any photos or memorabilia from Atlantus while growing up?

I thought some WW1 liberty ships were ferrocement as well. I think the ships mentioned as breakwaters (previous commentors) are examples. The idea sucked big time, from day 1 IMHO

A late 40s edition of Jane's fighting ships (reprinted in the 90s) mentions a number of concrete harbor tugs, small tenders and other coastal auxiliaries built for the Royal Navy as well. Besides saving on essential war materials, the other great advantage was that small concrete ships could be built outside navy yards, by construction companies with no previous shipbuilding experience.

I vaguely remember seeing the remains of a concrete ship beached on Hayling Island (England) in the 1940's.

we have her sister ship the ss peralta up in powell river serving as a breakwater.

Well whats left of it. Storms have torn it apart

@@calebbrooks3193 Yup, it's in a few pieces but it's still pretty visible.

"Let's Break Apart, Together"!

The biggest problem with all cheap to make hulls is people tend to go bigger than they would have, missing the point that the fitting out cost is no cheaper regardless of the cost of the Hull, hence many of these boats always look ""poor".

Got a 48 footer in my dads yard. Full keel beehive

I believe that ferrow cement kinda exspires at a point like 17 , 20 years. Also think these concrete boats are different from ferrow cement in the 70s

@@o9rgeronimo979 17-20 years? look at the remains of the mulberry harbours, I know of three ferro cement barges still here and from the same time and one that was broken up with jack hammers, they are basically reconstituted rock and will be with us for many decades to come. ps WWll ended a bit over twenty years ago☺.

@@o9rgeronimo979 Not as described in the video. the process is basically the same. Sheets of wire mesh bound tightly. Concrete is vibrated into the voids. the concrete is really used as much for structure as it is as a sealant.

They had all kinds of factories building liberty ships and people had no idea what they were doing. They tried, but... some liberty ships literally broke in half on the way to Europe. Poor welds, worse design

@@someotherdude the liberty ships were some of the earliest all welded ships, the design wasn't the problem, welding techniques at the time lead too cracking beside the weld, (if you don't do it right it will still crack today), and hence failure, it was unfortunately a learning curve that had tragic results but for everyone that broke dozens of others plyed the trade routes for years after the war ended, proving the design and their worth.

Just looked it up. She was named Helsal

I remember a day of sailing on Sydney Harbour with some friends in a ferroconcrete ketch.

I almost got on board her in 1959, no pier then, you got out to the crack in the hull. The tide was coming in during my attempt but my father and his brother-in-law stopped talking about baseball and noticed what I was about to do and ordered me back.

As memory serves, Drexel University has a concrete boat program, as well as plans for and operational concrete canoes. I suspect that more modern concrete mixes and coatings would make the vessels far more longer lasting as seaworthy vessels. It's just currently, we have no need for them, as steel isn't something that there's a great shortage of.

No they are concrete not cement.

@@neiloflongbeck5705 most people don't know the difference between concrete, which consists of aggregate and cement and just plain cement. I actually mixed up a light concrete mix and let it cure, as well as just plain cement to show the difference. The cement being exceptionally weak, the concrete cementing yet again its reputation as a tough construction component. ;)

Ah another Powell Riverite! Yes one was sunk just north of Willingdon beach a few years ago. I was down by the old arena site to watch it! Very hot day that was.

There's some wrecked WW2 cement tow barges seen at low tide near me , i was surprised how thin some hull sections were . Barnacles like them !

It’s at the end of the pier in Aptos and is clearly visible in Google Earth.

now it’s inhabited by sharks!!

Yep, but they had problems with the coolant pipes they had to run through the entire ship to keep it frozen, and the giant refrigerators that operated them. Yup they are remarkable things, it's an interesting substance, in the Arctic it might be a worthwhile construction material, but anywhere it's usually > 0C, Pykrete isn't viable because of the refrigeration needed. There's a famous bar in Sweden or somewhere, made entirely out of ice. They construct it from scratch every winter, enjoy a few months drinking overpriced vodka, then as spring approaches, the whole thing trickles down the drain. Pykrete is good because when you damage it, it's limited to a small area, and you can repair it just by adding more liquid Pykrete and letting it freeze in place. The wood fibres are very good at holding the ice together. But, again, the refrigeration is a problem. Ice doesn't conduct heat well, so you need to run pipes all over the place to keep the coldness flowing. Pykrete ships could operate without refrigeration in waters that are naturally just below freezing. But around there you'd have to worry about sticking to icebergs and any other random bits of ice. Even including seawater. Not practical for this planet. Maybe better on methane oceans somewhere.

I actually have target molds and I make targets for the kids out of Pykrete, it's nice cause it melts and leaves only sawdust on the range. But gives the kids (and me) a reactive target. They last for quite a while in the sun too.

unsinkable ha

@@codysmith605 Wood floats, so does ice. So not as silly as it sounds.

The titanic would like a word...

Look up Powell River Hulks to see them.

There was only a one barge made of pykrete and it was only used to test the viability of pykrete. Warships and aircraft carriers were considered but never when forward. Pykrete is quite strong and resistant to melting but tends to sag under it own weight when it warms making a poor choice for a large ship that will be sailing in to even Luke warm water.

@@jasonirwin4631 you’re right. I vaguely remember a modern marvels episode about this.

I was just thinking foam fillers in the aggregate would also improve the buoyancy of the concrete …

@@chrisbraid2907 With the above method the weight of the ship is close to that of a steel ship so no added buoyancy is needed unless you want to prevent sinking from a hull breach or storm swamping

I have walked out on that ship during some large waves and it was really sketchy, my friends and I jumped the fence and walked all the way to the end at night, this was probably in the late '80s

I grew up down there in the early 60s and always thought it was odd they made ships from concrete. There was a pier out to it and you could walk out on it and look at the broken back section.

We used to go to Sea Cliff from San Jose in the 60s. The ship had been run into the beach according to the info on the ship. The front 3rd (seaward side) had cracked apart from the main body. There were several information boards on board including pictures of the ship sailing (one or two pictures showed people dancing in a ballroom). Lots of people fished from the sides of the ship. Never thought as a kid or teenager to take pictures, we were swimming or looking around on the boat. We would go onto the boat each time we went to Sea Cliff beach. I heard decades later, while in CO, that an extra heavy storm and a very heavy undertow dragged the ship into the bay. I haven't been back there since '73, so everything after that is hearsay.

There was no pier in the late 50s when I was there, you had to wade out. When I tried I got almost to the broken part of the hull, where I hoped to find a way up to the deck, but my father saw me and thought a 9 year old shouldn't be doing that.

In other words. Cement, thats concrete baby.

One of my pet peeves for sure. I worked concrete construction, cutting and demolition for years and it used to drive me crazy that construction people didn't know the difference. I heard an argument between two guys. One said something about ce' ment and the other guy said "It's ce ment'". I say "No, it's concrete." I doubt the point stuck.

@@tomjackson4374 I don't understand. Kindly explain the point.

@@docmix see original comment in the thread, cement is one of at least 3 components of concrete, often components are 10 or more and cement is just one of them. The final product is concrete. Cement is what “hydrates” with water to harden the concrete. It is an exothermic chemical reaction. So another fun fact, concrete does not “dry” it actually “hydrates”. That’s my pet peeve. How long till the concrete is dry? Oh a couple hundred years…

@@snowmastr Thank you snowmastr, I did get that point of chemistry but what I didn't understand was Tom Jackson's use of the words "ce' ment" and then later of "cem ent". I thought that I was missing some technical detail however I now realise that they were just typos. Kindly excuse my obtuseness!

I think the ice and cement were mixed

Pyecrete ice and wood chip .Amazing Stuff HMS Habbakuk ? Idea was huge unsinkable Mid Atlantic aircraft carrier to cover the convoys. I think Canadians and Brits actually built something but it wasnt deployed due to costs and material shortages

@@glaslynx123 The material was good, but I don't think it got beyond prototype stage.

She was used as a nightclub briefly until a storm caused the crack in her hull.

Ah, the SS Crete Boom! Straight prow, counter stern, classic lines, sitting on the rocky shoal in the middle of the river. Lovely!

Can you reinforce concrete with glass? They're both brittle. The point of iron in concrete is surely that the iron bends a little to absorb stresses, where the concrete can't. In GRP, brittle glass supports flexible plastic. You can get rebar coated with epoxy or plastic, meant to protect it against corrosion. It needs to be inspected carefully for any missing spots of paint, which a worker tops up from a spray can. What about aluminium or titanium? Would they make decent corrosion-resisting rebar for marine concrete, you think? What do they use for bridges and docks by the sea?

Aptos CA, the only real attraction there beyond the really nice beaches, a cement ship at the end of a wharf. Used be able to go on it and people could reserve events on the ship but recently, lol like 2015 maybe now whenever that crazy storm hit half of the ship pretty much flipped on its side.

I'm glad someone else remembers that. I grew up in Sana Cruz county so I instantly thought at about it when I saw the thumbnail

@@MeansOfProduction209 …. I presume it’s still there. Haven’t seen it in decades

I've been to that one about 30 years ago

Does it turn green when it’s angry?

I also grew up in Santa Cruz and even fished off the ship though I never knew it's name but it was a landmark of Aptos it eventually did sink however that took till late 1990s so 50 plus years kinda puts to shame the narratives ascertain they weren't made to last

Not letting people on the highway know you have anything made of concrete is a great way to keep scum in transit from graffitiing your local history in gang tags and pentagrams. The best places are the ones not advertised because idiots can't find them.

@@madelaine2734 I wish. I was actually thinking about that when I watched the video. I may have a picture somewhere I’m hoping, but I kind of don’t think so. I should have gotten some over the years.

Cutting holes in a concrete submarine during renovation or major repair in dry dock to gain access move equipment in/out that won't fit through the hatches might raise some concerns about the ability of the repair to hold the very high pressures a sub can experience.

Although concrete has reasonable compressive capabilities, this is not suitable for a submarine, as all the pressure has nothing but the air inside the hull to compress against.

@David Wang My dad loved the boat and it was built really well apart from a non luxurious interior. After 30 years it was ready and my mum said "I dont actually want to go sailing around the world, I thought it would never happen"..... big blow that one. The amount of money that boat cost was truly massive. Plus he sold it for 40k ! Someone got a bargain. Glad to see other people know about this and yes he started building it in his garden, problem was it went into the neighbours garden and the road, eventually.

You dad is awesome! My ex’s uncle built a biplane in his living room in Pensilvania. It was made of wood and needed a VW engine to fly. He found it he could not get it out of the house without removing a wall. I don’t think he ever finished it. He passed away. He loved building it and he had flying dreams. He flew B-17’s in WWII. God bless these builders!

When I first got into boats, there was a fellow building a ferro cement ketch in Port Credit. I used to talk to him all the time and was looking at Jay Benford's designs. He got it finished and they launched it. Turned out to be be very badly out of trim (his mistake) and to get the ballast out they'd have to have bashed the hell out of the lower part of the hull. That was doable but the insurance companies wouldn't re-insure it. In the end, he ate $70k as a loss and had it broken up.

@@sabrekai8706 but not a problem with the material or design, many people have made poor boats in all the other materials as well.

@@CrusaderSports250 I agree with you. Epoxy was the up and coming thing, and sealing cracks and micro pores in a ferro cement hull would have been easy. I had a wood boat at the time, with some pretty severe rot in the keel, and floors. The bottom 12 inches of over 30 pairs of ribs were turned into dust. The previous owner had decided the boat wasn't stiff enough and poured about a half a ton of cement in, covering over various bits of steel scrap. Problem was, he'd not sealed the wood before pouring. The lime in the cement, always wet with bilge water, literally ate the lignin out of the wood. I ended up sealing the keel and floors with West System, several coats as it sank in like water in a sponge. I took one of the floors to a rifle range and bounced .22 calibre long rifle slugs off it for half an hour with next to no penetration. I have sworn by epoxy since then. But I have despised insurance companies even longer for the numerous ways they screw over their customers. This is just one such way. Don't get me going on my joys of car ownership.

@@sabrekai8706 never had a good experience yet with the leeches, but that's another tome it pays not to open. I currently have a steel twenty footer with 3/4 of a ton of cement in the bottom, needed to make the boat sit in the water, I was going to do a ships lifeboat but at twelve people to the ton and a thirty two person capacity I would need two tons to keep the prop underwater, not a boat I could transport easily, anyone fancy a twenty four foot ships lifeboat made in 1961 and still got its ministry plate, going cheap?, very seaworthy!😀, thought not!. Knew of a twenty five foot ferro motor boat, the owners had made it to master the techniques and so build a larger boat, that they never got round to building, seen it in some rather uncomfortable weather and it seemed to have quite a good motion, its weight carrying it through the waves rather than bouncing around on top, recently read an account of a couples trans Atlantic journey with a ferro yacht, as a material for boatbuilding it is not everyone's cup of tea but it has its place and many journeys have been made with them, much maligned because its not what the racers would use!!.

What? Walk away from a hole in the water into which you pour copious amounts of money? Lucky break !

I dove on the Sapona in July 1975 while spending time in Bimini, it's marked on google earth. It was my only experience with concrete ships but a lasting memory for sure!

Yes, a small percentage of each new generation can be deluded into thinking it's a good idea.