View Full Version : concrete hull
09-10-2012, 07:20 PM
Just looked at a 58 x 18 concrete hull boat on craigs list looks kinda like a sailboat it doesn't say what kind of boat it is. Any opinions about a concrete hull?
09-11-2012, 05:09 AM
I dont believe that I have ever seen any other kind of concrete hull than a sailboat hull. I suggest that you read a lot of info on building a concrete hull so you can figure out how to repair it. I know some were comercially made but most were home built. When you do your reading, figure out every way to cut corners and assume that the home builder did just that.
You can buy the boat cheap and over a period of time you might have some money tied up in it in the way of additions and improvements so keep in mind that insurance may not be available. Sorry I couldnt be of more help
09-11-2012, 05:20 AM
I would imagine that finding insurance would be a huge issue. There was a concrete sailboat near our dock some time ago. Memory serves me that he had all sorts of problems with spalling...
09-11-2012, 12:15 PM
Concrete boats can last a looooonnnnngggg time. Over time (lots) the reinforcing steel can start rusting caused by water leakage from micro cracks. This rusting results in spalling of the concrete and eventual distruction of the integrity of the structure.
If you PROPERLY built one today your great grand children might start to have problems.
There was a concrete sail boat in the Florence/Huntsville area in the 80s. It was a stable beast.
You need to do a search on ferrocement boats. These boats are actually a composite of rebar, chicken wire, and cement. As said they are almost indestructible. During WWII thousands of barges (called lighters) for moving supplies off of ships to the beach were built of ferrocement. In the 60's and 70's ferrocement had a very popular following. But they are also, almost all, very heavy and ugly. It needs to be a big boat before you begin to really gain any advantages in weight and volume. Most ferrocement boats are sailboats and I have seen other boats of ferrocement, but not a houseboat.
The only real advantage to ferrocement is ease of repairs. All you need is chicken wire and cement. But they are usually cheap compared to boats of the same size and age.
The disadvantages are, rusting rebar leeching out of the cement, heavy construction, they look bad (generally speaking), almost constant repairs need to the hull.
09-20-2012, 01:47 PM
Ike is dead on and Kaiser built ferrocement ships. Really indestructable except for what OHB said
Actually I think the building process is very interesting. You build a larger wood mold much like you would for building a wood boat. Then you build an Armature over the mold out of rebar, initially wired together, but eventually all welded together. This is the phase that takes the longest and it has to be done right. Everything has to be aligned properly or your whole boat will come out crooked. It takes along time to weld each individual rebar until you have a large rebar cage (the armature). Then chicken wire is spread over this, inside and out and wired to the armature. When that is done the cement is applied. But the crucial part is the cement has to be applied to the whole boat in one pass. Otherwise it cures at different rates and expands and contracts at different rates, resulting in cracks in the cement. (it's a lot like pouring the foundation for a house). If you have a big boat you need a lot of friends willing to help you make the cement and spread it. But if you do it right the cement cures in one piece. This is the part that is usually screwed up. Unfortunately the only cure is to take a jack hammer to it and remove all the cement and start over again.
After that the interior and decks are like building any boat.