3rd test of the Rockboat concept. On the way to making a house boat

The Rockboat concept is, as far as I have been able to find out, uniquely my idea. In order to fulfil my plan to make a house boat with the Rockboat technique, and live on  rivers and lakes I have to perform various tests of the concept before spending money on a fullscale floating home.

The two preceding tests were hull models in scale 1:10. They were aimed at finding the most optimal hull shape for sailing shallow waters without compromising sea abilities to much.

This test is too make a sculler/canoe/kayak with the planned hull form in scale 1:5 This allows for actually sit in it and get the full feeling of the hull performance.

The Rockboat principle is to laminate the hull with "bricks" of Rockwool to clad on the inner walls of the hull. The bricks are cut to form the outer shape of the hull. The outer surface can be covered with a skin for the desired purpose. For this build I plan to use glass fibre in my own secret blend of acrylic rubber concrete to make a semi hard surface, as I also keep it lightweight by not making it too thick and strong.

I think 5-7 cm spray concrete skin will be better for the full scale product. After all it is meant to possibly have to withstand ice and driftwood during its full life expectancy.

Here I have chosen 4mm sub-roof mdf plates. For the inner skin of the hull. They are water resistant, light and strong. To keep it stable under the construction I build them on a jig of cheap wood materials.

This is how it looks after the first day of work.

The inner hull will have a very box formed shape.  The outer hull shape will be created as I work with the "bricks" I cut from Rockwool.
Probably the best way to build a concrete boat

2nd test of the Rockboat concept. On the way to build a floating home

My obsession at the moment is to look into how to build a floating home with a completely new way of thinking. My idea is to build it in the same way and with the same materials used to build a house.

About my progress on building a Rockboat

The hull is the equivalent to the house foundation. Making it with watertight spray concrete on Rockwool, should be possible in theory, at least . So to test it out and avoid expensive failure I have to make different approaches to the task with scaled down models. This is my second test .

For the model I can only use a thin layer of plaster due to the weight. A full scale Rockboat can have armoured concrete between 5-7 cm and still have a shallow-going hull for use in canals and lakes .

The models are made from casual building materials I have had laying around the basement, but it gives some impression of a real houseboat .

The rear has a self emptying deck. For the sake of simplicity the Rockboat has no rudder nor engine. But the rear deck can be fitted with one or two outboard engines.

For the first test I just kept the boat in a line.

The test was on a local lake and it was a little windy so it was hard to judge from the test this day how the hull split the water. The water dynamics is improved, from the previous test hull to minimise energy consuming bow and aft waves.

Link to the 1st test Rockboat

The hull was made quite flattened at the bottom to allow shallow water use, but the test revealed that it lacked direction stability, particularly in the windy weather this day. This was kind of  predictable, so my backup plan is to fit a keel to the hull. The estimated depth for the full scale model is up to 50 cm, so a keel of about 7 cm doesn't add too much to the total depth.

1st test of the Rockboat concept. On the way to make a Float home model, scale 1:10

I have got this idea which obsess my mind. It is a more casual and sustainable living off grid on the lakes and the rivers.

To get the real vagabond feeling the vessel must have some sea ability in order to sail along the coast, at least when the weather is optimal. That rules out many of the catamaran constructions with a tiny house balancing on top, which are quite popular. It must be more a barge type of hull and narrow enough for rivers and slusses.

The typical British narrow boats are only about 2 meters wide to pass the narrowest canals and slusses. Most other countries in Europe have broader waterways, so I think a width about a railway compartment will be more comfortable for permanent living.

Boat hulls of ferrocement are strong, low maintenance, but also heavy. My idea is a combination of plaster, stonewool and armoured cement in the bottom. I am not aware that this has been tried before. Therefore I have to test it out in small scale to save costs.

Stonewool is fire resistant, insulating and non water absorbing. All of which is desired in a floating home.

My first idea was to cast the hull in a form. This is my first prototype :

But I realised that this construction is both heavy and quite difficult to make without the use of heavy machines. Therefore I came up with a new idea; to do this more like the way you construct a sort of tiny house. By craftsmanship . The hull can be constructed as a floating floor construction, only that it doesn't float on the ground, but on water. Therefore the stabilizing stiffness has to be the boat side of the hull, the inside!

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The hull is cut from Rockwool clad with glass fibre armoured plaster. It turned out to be impressively light and solid. I even lost it on the ground without harming the shell, but to make the bottom even harder I made the bottom with double thickness. The dolphin nose is to break the bow wave so it will glide more quiet in the water.

The sides made from some leftover wood and plexiglass I have used on a glazed terrace for my house. This served as frame for the Rockwool. The hull was then ready for a new turn with plaster. Both bottom and sides.

This is a downscaled model and it serves primarily to test the function of the material, but under way I try to think which building materials will be possible for a full scale model and how it can be built to withstand the forces of solid water rather than wind and rain which is the forces those materials are meant to withstand .

The hull is given a layer of paint too seal the plaster before it is fully hardened . It will now be allowed some days for hardening before testing it in the tub.

First test, February, 20th

My tub, it turned out,  wasn't big enough so I found a park pond for the test:

It floated higher than I expected, so I picked some rocks to fill into it .

It still kept stable, but as the last picture shows it picks up too much waves at the shoulders and it also seems as there could be made some improvements to the aft to release water more smoothly. After all, waves are energy consuming and also disturbs the environment. Minimizing waves is worth some more trials.

2nd test Float home model Press the link to see