Tuesday, September 12, 2017


Un blog de barcos y construcción naval
A ships' and Shipbuilding blog

para / for

Ingenieros   Naval archs.
Constructores  Shipbuilders
Navegantes  Mariners
Aficionados al mar  Sea Lovers 

Sunday, December 28, 2014

Preliminary ship dimensioning

Preliminary cargo ship dimensioning
in conceptual design stage

In following form you can do a preliminary estimation of cargo ships main particulars, based on a statistical analysis of actual ships, based on a unique objective goal, f.e deadweight. This set of dimensions can serve as a basis for a systematic investigation in order to get ship particulars that comply with the basic goal (as deadweight) and others as speed, cargo volumen, tonnage etc.

Click on this to get access to the dimensioning form

Thursday, September 25, 2014

World maritime day

 IMO celebrates World Maritime Day 
25 of September 2014

Today September 25th, IMO: International Maritime Organization  celebrates the World Maritime Day, designated by the United Nations to focus global attention to the safety of navigation and protection of the marine environment. 

This year theme of the World Day has been the implementation of international conventions issued by the IMO, noting that after the long work meetings and discussions by the working committees, after the approval of the relevant agreements, after the IMO promulgation of the formal agreements, it is necessary that the participating countries implement the adoption in their territories, by adapting and providing the necessary facilities and conducting training activities for the staff concerned and an effective compliance control. 

In the IMO website, the following video of the speech by IMO Secretary-General, Mr. Koji Sekimizu  during this day celebration, is shown

Thursday, February 20, 2014

"EDT Hercules" leaves the shipyard
"La Naval" from Sestao (Spain) last ship 

Time elapses very quickly, more than we usually realize. Yesterday we saw the departure of "La Naval" shipyard's last ship, built there and named "EDT Hercules", and she is the last because there is no one behind to build ... until they get new contracts. This situation is similar to that which occurred about 8 years ago, when this historic shipyard, "La Naval", changed ownership from public Izar to private Construcciones Naval del Norte (CNN).

By that date, October 2006, the LNG gas carrier "Bilbao Knutsen" was launched,  and I put in my other blog a brief post on the launching, with a beautiful night photograph taken by my daughter Natalia. She was the last Izar ship but it was not the last "La Naval" ship, that continued building many ships, some very important.

Sunday, January 12, 2014

Ship’s motions at sea

A vessel under sea has two types of movements:

  • Desired, to move the ship from one point to another and get she achieves the objectives for which  was built
  •  Unwanted, occurring mainly as a result of the waves and wind on the ship and causing trouble, inconvenience and danger to the vessel, persons and cargo, so they try to minimize them.

In this post I will only refer to the second type of movements, motions, relating to ships sailing on the surface.

The ship motion in a 3D space is made up, like any other solid, of the motion of its center of gravity and the movement or rotation around that point. The six possible motions, summarised in the following table, consist of three translations and three rotations, which refer respectively to the trajectory of the center of gravity and the rotations  around the main axes through it. Names are given in Spanish and English languages​​.

Reference axis
Turns r/ ref. axis
Longitudinal x
surge (avance)
 roll (balance ó rolido)
Transversal y
sway (deriva)
 pitch (cabeceo)
Vertical z
heave (arfada)
 yaw (guiñada)

In the following drawing the three axes are shown, for which the movements of translation and rotation relate.