April 21, 2010
To lift the catamaran out of the water or into the water four removable lifting lugs can be bolted to the deck at specific lift points. It is then possible to lift the catamaran out of the water with a big, movable crane.
Although theoretically the lifting accessories have been designed and calculated for the full weight catamaran, it is always advisable to keep the cat as light as possible for lifting it completely out of the water.
The lugs must be attached to the hull only for the time of lifting the cat, otherwise the high tensile bolts will rust and it will be very difficult to remove them.
|The lugs are made of steel and have been
cut from a piece of I beam. Only the rider bar on top has been
welded to the lug.|
The six bolts that attach each lifting lugs are made of high tensile steel.
The aft port lift lug is number 1, the forward port is number 2 and so on, in the clockwise direction. The number of each lugs is punched on the underside, with number 1 with 1 punch, number 2 with two punches and so on.
Each lift lug has been designed to lift a maximum of 7.5 tons, thus together the four lifting lugs can lift a total weight of 30 t, the maximum full weight of the cat. This limitation is due not just because of the lugs themselves but also due to the counterplates to which the lugs are bolted.
|It is absolutely imperative that the maximum angles of the cables attached to the lift points are not greater than the angles specified below. Irreparable damage to the hull might otherwise result.|
When looking at the cat from the side, each cable must have an angle not greater than 20 degrees off the vertical. In other words on top the two cables must come together at a maximum angle of 40 degrees, making it necessary to use a fairly tall crane since the minimum height of the crane hook must be 21.5 meters
Looking at the cat from the front or back, the two cables at the front or at the back must be parallel. This makes it necessary to use a substancial steel spreader.
This photograph shows one end of the spreader used to
lift the catamaran.|
The spreader itself is a steel tube with an outside diameter of 200 mm and a wall thickness of 10 mm.
|The lifting truck must be able to lift the
weight of the boat plus resist the momentum caused by the extension to the
side of the crane arm.|
This is the limiting factor and the reason a such big sized crane truck is needed.
The result is a flying cat.
When this photograph was taken, in December 2004, the cat weighed 15,7 tons and all the material used to lift the cat, like chains, shackles and spreader another 1.2 tons.
For the seaside transport the upper part of the catamaran, the house, has to be
separated from the lower part, the hulls.
The house is now bolted to the hulls. After the final assembly after the transport the bolts will be substituted with welds. Some parts have been tack welded to assure stability during the construction. Those tacks will have to be cut before separating the two parts.
The truck fits between the hulls of the cat.
The PH8 should be positioned on its cradle in correspondence with the frames 5 and 11.
The bottom part is 16.69 m long, 6.73 m wide and weighs app. 20 metric tons.
The top part is 12.50 m long, 6.73 m wide and weighs app. 20 metric tons.
The top part is 12.50 m long (including back navigation light), 5.30 m wide and weighs app. 4 metric tons.
To minimize any damage that could occur during the lifting of the catamaran, instead of steel cables or chains four belts are used. Each belt can lift 8 tons (pale blue color code).
The lugs are attached to the cat with six 14 MA high tensile steel bolts and nuts. Where possible washers with an OD of either 28 or 42 mm are used on the underside.
When the lugs are not attached to the cat the holes are filled with regular 14 MA stainless steel bolts. On the outside, underneath the bolts, a bit of 3M 5200 FC make the holes watertight.
To tighten and remove the stainless steel bolts a 22 mm ratchet wrench is used. For the high tensile bolts a 14 mm hex key, located on the tool panel of the starboard engine, is used.
|24||High tensile steel bolts and nuts||14 MA, 80 mm|
|24||Stainless steel bolts and nuts||14 MA, 40 or 50 mm|
|24||Steel washers||OD 28 and 42 mm|
|Lifting belts||SpanSet Italia||www.spanset.it|
|Shackles, 8 tons each||SpanSet Italia||www.spanset.it|