Ad Hoc Marine Designs Ltd. is design Consultancy Company that offers a wide variety of technical services. Offering: Naval Architecture, Marine, Structural, Hydrodynamic and first principal design calculations in the High Speed; Paramilitary; Workboat; Crew Boat; Patrol boat and marine related structures such as pontoons world wide.

With a combined 60 years of experience in shipyard production and design, we offer practical hands-on advice in all aspect of marine design and naval architecture as well as onsite support.

Being authors of many international technical papers and text books, we are able to draw upon their vast technical resources for quick effective problem solving that offers a wide variety of technical services such as:

Concept design of specialised craft

We specialise in novel concepts. Creating concepts that are sometimes beyond the envelope of generally accepted naval architecture as well as using existing philosophies to design vessels that offer a unique role.

Detailed Structural Design

Experts in the design of aluminium structures as well as many years of experience with steel and composites; including composite waterjet ducts and waterjet grills. In addition, using advanced techniques in reducing the structure weight on high speed steel hulled patrol boats.

John Kecsmar’s expertise was recently highlighted in an article which focused on Fabrication and Fatigue Failure of Aluminium was published in the June/July 2012 edition of Professional Boatbuilder magazine no.137. Reproduced with kind permission of Proboat magazine.


FE Analysis

John Kecsmar has been using FEA since the early 1990s to validate first principal calculations as well as research into fatigue hot spot stresses in details design. The most common reason for using FEA is establishing global stresses on multihull vessels, to facilitate the detailed structural design. It allows for quick iterative options and investigating different scenarios quickly. Using FEA on detailed joint analysis highlights problem areas and allows for improved fatigue resistant structures.

Construction Advice

We can advise on just about any method of construction whether it is for a new build or a repair or general advice. Structural design is not just about calculation, it is about ease of fabrication. Being heavily involved with a shipyard, implications on cost, time and quality of the fabrication are often at variance with the design intent. As such, this often requires a unique solution to each problem.

Corrosion Advice


Nigel Warren was an expert on corrosion. His book “Metal Corrosion in Boats” has become the bible for many amateur and professional surveyors alike, including the USCG. As such Ad Hoc Marine Designs Ltd can draw upon resources and database of information on all things related to corrosion.

This is a topic that crops up very frequently when metals are asked to combat the extremely corrosive nature of seawater. Situations where advice has been given to hundreds of clients include pitting corrosion in stainless steel shafts, unusual anode performance, rapid and deep corrosion of aluminium hulls, electrolysis damage from faulty shore supply and compatable materials and fasteners.

Specialist in SWATH, Catamaran & Low Wash Naval Architecture.

Both Nigel Warren and John Kecsmar were responsible for the concept and detailed design of two fast SWATHs, PATRIA and the two sister PTC SWATHs operating out of Plymouth UK all built by FBM Marine. The latter was a subject of two RINA papers- International Symposium on the Safety of High Speed Craft 6th and 7th Feb. 1997 and SURV 6 Conference 17-18th March 2004. Patria at 31 knots is still the fastest SWATH in the world and is currently operating in Korea for Dae-A ferry services as “MV Sunflower”. In addition to these two SWATHs Ad Hoc Marine Designs Ltd were the structural and naval architectural provider for the Lockheed Martin SWATH of the SLICE© vessel.

Many variations of high speed catamaran hull form have been model tested for resistance including variations in beam to draft ratio, length to beam and hull shape from semicircular section to rectangular section. A unique easy-to-build flat bottom, rectangular shape has also been tested. Coupled to this research was the investigation into low wash hull forms. This resulted in the concept and detail design of the three low wash 23m high speed riverbus catamaran craft operating on the Thames UK and three 15m monhull fast passenger launches also operating on the Thames designed and built at FBM Marine.

Noise and Vibration Advice

With accumulated data from many vessels a practical prediction for other designs can be made. Advice on meeting target noise levels can be given at the design stage. Problems in service can also be addressed.

Rapid resistance model testing & comparative studies

The use of a 21m test tank for simple resistance experiments and sensitivity analysis of various hull forms or appendages including wash analysis.
This simple test tank can give quick inexpensive answers to an engineering degree of accuracy and avoids the normal and very costly model making and testing facilities.

Re-Engining advice

Ad Hoc Marine Designs can provide expert and practical engineering solutions tailored to every requirement. From removal of engines to reviewing alternative engine solutions for speed/fuel consumption to propulsion options such as waterjets and controllable pitch propellers.

Independent trial analysis and advice on rectification

Numerous sea trials have been conducted all over the world and as such Nigel and John are well suited at reviewing and conducting independent sea trials. This ranges from procedural reviews to act as a mediator, to problem solving when results are not as expected and/or giving solutions to overcome any problem areas, to conducting the sea trials to ensure the smooth running to satisfy Class/Flag/Client.

Independent design reviews

Nigel Warren and John Kecsmar have designed many different types of vessel over the years at various companies. These range from low wash vessels to SWATHs to fast ferries, all in various hull forms, from monohulls to trimarans. They are well able to conduct independent reviews.

Heavy lift arrangements

Ad Hoc Marine Designs are aware of the day to day requests and problems that are thrown up by working closely with production. Lifting arrangements to facilitate production schedules and limited spaces are second nature. Designing lifting structures to enable subassemblies through to complete vessels are easily performed to suit every budget and time schedules of any shipyard or client.

On-site technical design support

Reviewing everything from fabrication to designs from minor assemblies to complete survey of vessels. Acting as independent advisors of: build quality, design and in the administrative roles to accommodate both Classification Societies and Flag Authorities in overcoming obstacles, problems, errors created by production or otherwise.

Customer Representation

For a potential contract through to a full contract. Acting as independent technical advisors from pre-contract through to shipyard build phase to delivery, ensuring all aspects are addressed to the client’s wishes.

Repair and Redesign work.

Ad Hoc Marine Designs has recently branched into redesign work on existing vessels. This has ranged from redesigning bows for major structural support to act as “bumpers” for coming along side Piles for berthing, to High speed rudders on fast ferries to the structural redesign of a GRP patrol boat.

Safety Case studies

John and Nigel have been involved with Safety Case studies for the UK MoD, MCA and other bodies, Ad Hoc Marine Designs are able to take part in all aspects of case studies regarding safety of vessels operation and design.

Design of marine related structures such as brows, pontoons etc

Ad Hoc Marine Designs in-depth marine-based engineering knowledge with shipyard design experience has been put to good use in recent projects. Designing Link-Span walkways, to Brows – for passenger transfer between vessels at sea, to anchor handling equipment, to Floating pontoons in Poole Harbour, UK to name a few. Any structure, buoyant or otherwise are all part of our repertoire.

Inclining Experiments & Stability Analysis

We are able to perform inclining experiments on any type of small vessel, Ad Hoc Marine Designs Ltd has the experience to cover all craft types. Once the inclining experiment is completed, a report is written up for Class/Flag approval. This also enables Ad Hoc Marine Designs Ltd to produce stability reports either as a preliminary investigation all the way up to a full Trim and Stability Booklet for use onboard. The stability analysis is performed using the Wolfson Units Stability Suite of programs.

Additionally, complete “weight and centre” reviews to enable a full Light Ship Survey can be conducted.


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