Amsterdam Houseboat Trivia, page 3

Nederlandse versie
Final page
Houseboatpage #1
Numbers and history
Types of houseboats
Houseboatpage #2
Provisions on board
Typical on a houseboat
Houseboatpage #3


As you could have read under types of houseboats, only the 'arks' on a concrete hull are blessed with an almost maintenance-free under-water-ship. All ships on a steel or iron hull must be taken out of the water every three or four years for treatment against the inavoidable rust and to be checked for signs of wear and tear.
Ships that still sail wear off faster than permanently moored houseboats and the maintenance interval mostly depends on conditions in the insurance policy or the mooring permit.

The most popular ways of getting ships out of the water are the slipway and the drydock. In some cases a hoisting crane or boatlift is used, but only for the smaller vessels.
A slipway is a kind of railway track which runs down a slope till under water. On it are several special carts, moved by a winch. The carts are lowered in to the water, the ship is manoeuvered above them and then secured with ropes. Once everything is in place the winch pulls the carts with the ship on to dry land. To make it clear i've drawn a sketch of a slipway (GIF 7Kb).

In a drydock a ship comes out of the water straight up, which is very practical because then you won't have to empty all the shelves and cupboards in the house to avoid mayor household disasters. A drydock is in itself a large container. Once the ship has entered the dock can be pumped dry and the work can begin. A fixed dock is shut with watertight doors before pumping and a floating dock is so to speak 'pumped afloat'.
A floating dock is a sort of submersible barge. It is sunk far enough to allow the ship to be manoeuvred in. Then pumps start to bring the two above the water.
I've also made a drawing of a floating dock(GIF 8Kb) .

Once a ship is out of the water it is cleaned with water under heigh pressure, more than 100 atmosphere (1470 psi) to get rid of waterplants, alge and stuff like small shellfish. Then the hull can be inspected.
The first inspection is a visual one for deep rust and/or loose rivets. Then a ship is often 'knocked', hit on with a big hammer to hear (frequency) and feel (buoyancy) whether the plates are still thick enough. The required amount of plate differs on the use of the ship and on the insurance company, in general 3 to 4 millimeters is considered good for a permantly moored houseboat.In some cases a ship has to be measured for thickness. The old way consists of drilling holes on supicious spots and measuring the plate. Nowadays a lot of inspectors have ultrasonic measuring devices which only require thourough cleaning at the spots to be measured.

As soon as the ship is found in order or is repaired it gets coated for the next four years. Until recently with tar or tar-containing products, but this will soon be over due to new environmental regulations. Unfortunately the quality of the given alternatves is not proven yet. New regulations do bring up the price because shipyards have to meet tougher requirements.
Don't get me wrong, I do support environmental improvements but find it sad to see that it will probabely mean for some people that they'll have to leave their floating house because they cannot afford the maintenance anymore. The new rules may also mean the dissapearance of some characteristic small shipyards in Amsterdam.

Going to the shipyard is probably the biggest and most costly event that regularly returns.You're out of a house for a week, or can camp in it on the shipyard, without water, gas and telephone. The costs can add up to 2.000 Euro and that is if everything is o.k. Repairs vary from 300 to thousands of Euros. On top of that you have to take a leave from your work because you have (or want) to be present wen repairs or inspections are carried out. Welding and grinding for instance, bring along an increased fire-hazard. But, if all goes well it brings you years of house-boating-fun and freedom!

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