a boat on the water

Technical Project with Stability Study for Vessels in Spain

A technical project with a stability study is required when modifications affect the operational regime, weight distribution, or structural configuration of a vessel.

In Spain, the Spanish Maritime Authority (Capitanía Marítima) may require technical documentation to verify compliance with safety standards, stability criteria, and applicable maritime regulations, particularly when changing from recreational use to commercial operation or after significant technical modifications.

When Is a Stability Study Required?

A stability study may be necessary in situations such as:

  • Engine replacement or an increase in installed power

  • Structural modifications affecting weight distribution

  • Installation of heavy equipment

  • Change of registration (cambio de lista) or commercial use

  • Administrative regularization following modifications

Any alteration that affects the center of gravity may directly impact vessel stability.

a small white boat in a body of water
a small white boat in a body of water

Calculations Included in the Stability Study

The technical stability project may include:

  • Hydrostatic curves

  • Calculation of GM (metacentric height)

  • GZ stability curves

  • Static and dynamic stability analysis

  • Verification of damage stability (when required)

These calculations determine the vessel’s behavior under heel conditions and operational loads

woman in black long sleeve shirt using macbook pro
woman in black long sleeve shirt using macbook pro

Weight Distribution Assessment

The study evaluates:

  • Longitudinal and transverse center of gravity

  • Ballast effect

  • Cargo influence

  • Impact of new installations

  • Variations in trim and list

An improper weight distribution may compromise navigational safety.

A couple of boats parked next to each other
A couple of boats parked next to each other

Compliance with Maritime Regulations

The project must comply with:

  • Spanish maritime legislation

  • Applicable international stability criteria

  • Specific requirements according to vessel length and type

  • Administrative requirements of the Dirección General de la Marina Mercante

Proper regulatory justification is essential for approval.

A sailboat is docked at the end of a pier.
A sailboat is docked at the end of a pier.

Technical Documentation for the Spanish Maritime Authority

The technical file may include:

  • Detailed technical report

  • Stability calculations and hydrostatic data

  • Stability curves and graphical representations

  • Updated vessel drawings

  • Signed engineering certification

All documentation must be clear, technically consistent, and defendable before the Administration.

a sailboat docked at a dock in the water
a sailboat docked at a dock in the water

Application Across Vessel Types

A technical project with stability study in Spain applies to:

  • Recreational vessels

  • Yachts and superyachts

  • Commercial vessels

  • Major structural or operational modifications

Each case requires individualized technical modeling tailored to the vessel configuration.

a sailboat on the water
a sailboat on the water

Technical Safety and Administrative Validity

A properly executed a stability study:

  • Ensures safe navigation

  • Reduces operational risks

  • Facilitates administrative approval

  • Guarantees regulatory compliance

The involvement of a chartered naval architect and marine engineer ensures technical rigor and documentary validity.

A boat is docked at a dock with a cargo ship in the background
A boat is docked at a dock with a cargo ship in the background