Contact Details


5 Brighton Way
SN14 0YR

Philip Henderson

Technical Director

07592 511 446


James Hare

Business Director

07592 511 449


Information / Enquiries:


Please also use our contact form


H2NA is always willing to discuss your specific needs regardless of size, please feel free to approach either of our company directors using the Contact Us page. The following list details current experience although should your company require something subtly different then please get in touch as we are looking to expand into new specialisations.

Stability Information Books

H2NA staff have extensive experience (since 1996) and success with the creation and modification of a wide range of ship Stability Information Books (SIB's). Documentation has been approved by Lloyd's Register of Shipping (LR), Maritime & Coastguard Agency (MCA) or other MGN280 Certifying Authority (i.e. MECAL, SCMS) as necessary. The generation or update of this key ship document is part of our core business and can be completed either as a stand-alone task or as part of a wider stability analysis. Good working relationships with the UK regulatory authorities and a thorough understanding of their requirements enables H2NA to complete such tasks to demanding timescales.

Computer Loading Instruments

H2NA has extensive experience in the production and use of a range of ship Computer Loading Instruments (CLI's). A detailed knowledge of Seasafe (GSTAB), LOADMATE, Shipwrite, Paramarine and LocoPias has provided an appreciation of their relative merits and shortcomings.


In addition to the above core expertise H2NA is keen to expand this knowledge base and use other computer models and software packages to meet a customer preference.

Stability Analysis

H2NA is proficient with the following:

• Calculation of Hydrostatics

• Compliance with Class and Flag Requirements

• Intact Statical Stability Assessments

• Deterministic Damage Stability Assessments

• Probabilistic Damage Stability Assessments

• Production of Critical KG Curves

• Production of Damage Stability Templates (Mode of Loss / Carpet Plots)

Individual requirements can also be accommodated so please do not hesitate to contact us should your specific need not be covered above.

Inclining Experiments & Displacement Checks

Extensive experience inclining both Commercial and Naval vessels makes H2NA the perfect choice to conduct an Inclining Experiment or Displacement Check. The company is able to provide full management of this vital activity (planning, liaison with all parties, conduct of experiment, results calculation, submission for Class/Flag approval) or simply provide additional resources to support your own team as required.

Additional services such as:

• Liaison with Classification Societies / UK MCA

• Ship growth management

can also be provided.

Feasibility & Design Studies

Significant practicing experience in the field of Naval Architecture has provided H2NA with the breadth of knowledge required to undertake a wide range of Naval Architecture assessments against a diverse set of customer requirements.

Dry Docking Calculations & Management

Both H2NA Directors have significant experience docking and undocking ships between 3,000 tonnes & 40,000 tonnes in the UK. This experience of 25+ vessels has developed a thorough understanding of all the procedures, activities and assessments involved during a docking or undocking.

Towing Calculations

Naval Architecture support for ship towing can be provided Worldwide in support of Class and Flag requirements.

Refit Activities

Our staff are qualified to and experienced at providing Naval Architecture support before, during and after ship and large boat refits. Regardless of whether your requirement is to manage a multi-million pound major ship conversion or a re-certification and cosmetic upgrade our team stands ready to support your company deliver a successful project.

Local Structural Design & Analysis

An in-depth knowledge of structural assessment techniques and computer tools provides H2NA with the skills necessary to design or modify ship structure. This work can also be submitted to Lloyds Register for Plan Approval depending on your specific needs.

Flight Deck Design & Analysis

Recent experience with the provision of flight deck structural clearances across a range of naval vessels and military aircraft; assessed to both Naval and Commercial (LR) rules.


Independent material state verification inspections can be carried out including, but not limited to, the following:

• Watertight Integrity Surveys

• Downflooding Point Surveys

• Safety Equipment Plan Approval Surveys

• Escape Plans – Development and/or audit to approved plans

• Valuations and support with sale or purchase agreements

• Laser Mapping

Ballast Water Management Plans

H2NA has recently produced a number of Ballast Water Management Plans to LR Requirements for a wide range of vessels. This has included all Naval Architecture Ballast Water exchange calculations / plans as well as documenting system information in consultation with equipment manufacturers and shipbuilders.

Other Services Available:

Feasibility Studies

• Ship Trials – Development of Trials Plan and Event Management

• Model Trials - Liaison with QinetiQ Model Basin and Ship Owner Results Interpretation



H2NA Company Directors have a combined experience of over 30 years working with the UK Ministry of Defence focusing on both commercial and large naval vessels. This has provided a thorough understanding of the requirements of MoD Naval Authority, LR and MCA rules and regulations.


Independent Audit

Chartered Engineers registered with UK Engineering Council and Members of RINA provides your company with the assurance of a professional, independent and commercially discrete service.


Drawing Office

Our drawing office is equipped with the latest equipment and software with skilled operators capable of creating or modifying customer drawings as required.


Class / Flag Approval

H2NA regularly liaises with MCA, LR, DNV.GL & BV Surveyors. Should your requirement necessitate it, we are able to develop relationships with any member of IACS. We also maintain constant working relationships with other Certifying Authorities (UK & Europe) acting on behalf of Flag.


Customer Support

If your company either doesn't have its own Naval Architecture expertise or wishes to temporarily increase its numbers or experience, H2NA is able to provide support to a wide range of requirements on an ad-hoc or more permanent basis. Support can also be provided with tasks ranging from requirements definition through to evaluating tender responses or design solutions.