Friday, March 8, 2013

Stability of deck barges and pontoons

In a previous post I included an approximate procedure to estimate the stability of cargo ships in the preliminary design stage, but a blog reader pointed out to me that it was not good enough for the special case of   deck barges and pontoons , which are artefacts carrying all load above the deck. Due to this so special condition these floaters (they are not conventional ships) have received a different stability consideration in the IMO  regulations and I have been preparing a specific procedure for estimation of their stability.




In the form that opens by clicking the following link, GetxoNaval ship dimensioning program is open and selecting the deck barges stability tag, the user is requested to input a few data of the barge / pontoon and he gets a suitable information about its stability in the specified loading condition. After the form a user guide is shown and a results interpretation.


Sunday, February 17, 2013

WindFlip: A barge to transport and position wind turbines
Innovative System from WindFlip AS

 Electric generation by wind turbines is increasing dramatically in Europe and other areas and placement of turbines at sea (offshore) is one of the booming posibilities due to the increased performance and environmental advantages that are got. However transport operations and placement of wind turbines at sea pose a significant cost and require the use of special vessels dedicated to these tasks.


 Recently, new ideas are being released to solve or ease these problems and one of the most recent is the use of special barges, towed, low cost, as the type called WindFlip.


 WindFlip is a simple barge which loads the complete wind turbine, is towed to its site at sea and there is ballasted and flipped by stern up to the vertical and then the turbine pedestal end is buried in its working position. WindFlip is unballasted then by injecting pressurized air in the tanks and proceeds returning to port. So simply said it seems easy, but I suppose it will be quite complicated, nevertheless it seems a bright idea and hopefully satisfactory.

This video briefly shows an outline of the operation, where nothing can be seen how to move the turbine from its location on shore up to its place on WindFlip, but I do not think it will be a big problem.

A typical WindFlip is about 100 m long and 30 m wide and such a barge could carry a complete wind turbine of 65 m and 15 MW  power.

WindFlip uses an old idea, the pivotting ship type named FLIP (Floating Instrument Platform), to solve a new problem. The FLIP is as old as 1962 and was used by the United States navy as an ocean research platform, providing to the involved scientists  a still and comfortable workstation, compared to that offered by a ship floating and moving among the waves. The Ship-Technology.com site describes and shows the ideas and reality of this ship.