Sailboat with solar panel on a stand.

Technical Project for Vessel Legalization

A technical project for vessel legalization is the documentation required by the Spanish Maritime Authority (Capitanía Marítima) when a vessel needs administrative regularization following structural modifications, technical alterations, or change of use.

In Spain, maritime legalization must be supported by:

  • A detailed technical report (memoria técnica)

  • Updated general and structural drawings

  • Justification calculations

  • Verification of regulatory compliance

The objective is to demonstrate compliance with Spanish maritime regulations and ensure the vessel’s structural safety and stability.

When Is a Technical Legalization Project Required?

The Maritime Administration may require a naval technical project in cases such as:

  • Structural modifications to hull or deck

  • Engine replacement or a change in installed power

  • Alteration of weight distribution

  • Installation of new technical systems

  • Change of registry (cambio de lista) or modification of use

  • Regularization of pending documentation

Each situation requires a specific technical verification adapted to the vessel’s configuration.

white and blue yacht on dock during daytime
white and blue yacht on dock during daytime

What Does a Vessel Legalization Project Include?

Un proyecto técnico naval para legalización suele incluir:

  • Memoria descriptiva de la actuación

  • Planos generales y de detalle

  • Justificación estructural

  • Cálculos de estabilidad (si aplica)

  • Verificación normativa

  • Certificados técnicos complementarios

La documentación debe ser coherente, trazable y ajustada al tipo de embarcación.

a blue and white boat being worked on
a blue and white boat being worked on

Compliance with Spanish Maritime Regulations

The project must comply with:

  • Spanish maritime legislation

  • Requirements of the Dirección General de la Marina Mercante

  • Applicable stability criteria

  • Relevant technical standards and rules

The purpose is to ensure the vessel can operate legally and safely in Spain, without administrative risks.

white and black ship deck
white and black ship deck

Importancia del Estudio de Estabilidad

Cuando la reforma afecta al peso, centro de gravedad o estructura, puede ser obligatorio incorporar:

  • Curvas hidrostáticas

  • Cálculo de GM

  • Verificación de estabilidad intacta

  • Análisis de seguridad transversal

Un estudio mal planteado puede generar requerimientos o rechazo del expediente.

Boats and cranes in a sunny harbor.
Boats and cranes in a sunny harbor.

Importance of Stability Study

When modifications affect weight, center of gravity, or structure, it may be mandatory to include:

  • Hydrostatic curves

  • Calculation of GM (metacentric height)

  • Verification of intact stability

  • Transverse safety analysis

An incorrectly prepared stability study may lead to administrative objections or rejection of the application

A large white sailing ship docked at a pier.
A large white sailing ship docked at a pier.

Procedure Before the Spanish Maritime Authority

The standard legalization process includes:

  1. Preparation of the technical project

  2. Submission to the Maritime Administration

  3. Response to administrative requirements (if any)

  4. Technical inspection (when required)

  5. Issuance of updated certificates

A complete and technically sound project reduces delays and facilitates approval

A boat is covered with a tarp.
A boat is covered with a tarp.

Scope of Application

A technical legalization project in Spain applies to:

  • Recreational vessels

  • Yachts and superyachts

  • Professional-use vessels

  • Sport boats

Each category requires analysis adapted to its length, displacement, and operational regime.

A large white sailing ship docked at a pier.
A large white sailing ship docked at a pier.