Investigation 4 

A personal account – P. Constantine

 

Understanding the core information

A Naval Architect

Computers?

Source information

To investigate the nature of the hull of the ship it is important to understand that the core information has to be derived from the book The Sutton Hoo Ship Burial by Rupert Bruce-Mitford, as described in Investigation 1 on this website.

The present understanding of the ship has to be based primarily on the drawings in that book as described in Investigation 2 on this website.

The original basic drawing is:

Fig 185. Science museum Provisional plan drawn under the guidance of Lt. Cmdr. Hutchison, Sept 1939. An authenticated, signed-off copy is in Ipswich Museum where it was recently discovered by Joe Startin.

             Anything and everything written about this drawing is the ‘opinion’, also called an ‘interpretation’, from other people, usually having various levels of expertise in related archaeological fields. This and the other ship drawings can be ‘qualified or clarified’ by additional material from accounts and pictures from what was actually found in the ground during the excavations. It is worth repeating this section from Investigation 1 that tries to sound a note of caution, because even ‘experts’ may not be wholly in agreement about the significance of what some ‘evidence’ may be:

‘The people concerned with the excavations in 1939 had very little time to closely examine what was being found and sometimes they offered their opinions by making educated guesses at the relevance of what they were seeing. After the war the people excavating had more time and they sometimes sought to corroborate or to elaborate on what had been suggested in 1939. This means that in the book there may be more than one description of certain individual details. There will be the 1939 version and then another later version or versions that were produced following a more careful and detailed post-war investigation.’

 

 This possible lack of certainty can be illustrated by the Nydam ship (Investigation 3b) whose actual planks were recovered. In rebuilding them there have been different opinions about the shape of the ship that would result from reassembling the planks, as shown in this diagram on page 33 in the publication Das Nydamboot by Angelika Abegg-Wigg. Four shapes for the ship have been produced by different ‘experts’ on four separate occasions.

The Sutton Hoo ship, as it was discovered, had the open stern and on this issue all the experts are in agreement, the ship had split apart – it was not constructed like this. To remedy this, two other drawings were made and they have been very influential in the general understanding of what the ship looked like, as they are contained in the book. They are:

Fig 324. An early 1973 Lines plan drawn and annotated by Colin Mudie, called Drawing 202.3

Fig 325. The Plank and Rivet plan which is a British Museum drawing.

The Lines plan Fig 324 is a fold-out that appears as a series of lines showing the shape of the outside skin of the craft.

Most people do not pay too much attention to this drawing as the next drawing Fig 325 is much more interesting. It is a long drawing on a fold-out page that shows the ship with all its rivets, ribs and tholes. A couple of drawings to the right show the shape of the ribs and puts the planks in place over them. It is described in the book as an ‘Archaeological reconstruction of the Sutton Hoo ship, based on the 1939 photographic record and information gained in the 1966-7 re-excavation.’ This is the drawing that best seems to illustrate the ship.

Each of the 3 drawings is different. Each has features that are very likely to be accurate representations and some probable inaccuracies. Drawing 185 and drawing 325 are both illustrative and 325 is based on 185 but with additions, as mentioned above. However, there are differences that need some explanation, especially as Mudie’s number 202 drawing went through a series of different versions. The version printed in the book is 202.3, but additional versions were produced up to 202.8 and this drawing was in the possession of the investigators.

 

Naval Architect

To make design changes there have to be reasons. For Mudie to pull the planks together, other parts of the hull would have to change also - and this needs expert understanding. The investigation team went in search of a highly-qualified naval architect and were fortunate enough to be recommended to contact Paul Handley who has an Honours degree in Ship Science, is a Member of the Royal Institute of Naval Architects (MRINA) and a chartered Engineer (CEng). It is useful to understand the work that any expert has undertaken, so the following information may serve to show the range and flexibility of Mr Handley’s operations. When ideas are put forward about any subject there are questions about the basis of those ideas. It is inevitable that concepts may be questioned, depending on who advances them, so what is the expertise and experience of the person?

 Paul Handley

Mr Handley has been the winner of three International design awards - Boat of the Year 2002 - British Nautical Awards, Coup de Coeurs 2004 (Sailboat of the year) - Voiles et Voiliers, France and Dinghy of the Year 2005 - Sailing World, USA. His designs include the development of new recreational boats built in Europe and USA and distributed internationally, including the RS Feva (junior double-handed sailing dinghy), RS Tera (junior single-handed sailing dinghy), the RS Quba, RS 100 performance single-hander and the K1, K2, & K6 keelboats. He did the production design for the 9m cruiser/racer sailing-boat Mustang 30 and was responsible for the structural design for EcoCruiser D-37 a low-drag motor cruiser. He has provided Recreational Craft Directive information for the project design of production rowing sculls and also a pedalo for roto-moulded HDPE construction.

It was important for the investigation team that Mr Handley’s work was not just restricted to a single type of craft, but crucially included rowed craft and experience with a variety of different materials. There was everything from sailing boats, keel boats, motor boats and even a plastic pedalo. The investigators were about to pose questions concerning (possibly) the most extreme and unusual craft that most naval architects will ever see.

His early career began as an engineer at the Wolfson Unit for Marine technology and Industrial Aerodynamics at the University of Southampton, he conducted research and consultancy for recreational and commercial boats, including hydrodynamic and structural design, research into the stability of yachts (Co-author of University report on Stability of Yachts in Breaking Waves) and the design of recreational, commercial power craft and lifeboats.

In addition to his design work Mr Handley has undertaken a very wide range of technical and advisory work such as consultancy for the International Council of Marine Industry Associations (ICOMIA), for whom he prepared comparison guides between ISO and US ABYC boat-safety standard requirements. He was consultant to the British Marine Federation (BMF), the DTi and the Royal Yachting Association (RYA). His work on the EC Recreational Craft Directive included preparation of the guidance manual on RCD (EC Directive 94/25/EC) requirements for BMF. Technical support to RYA when it was acting as an RCD Notified Body, including support on UKAS accreditation requirements for RYA. Expert witness support for Dti. RCD consultancy for manufacturers of motor cruisers, sailing cruisers and Rigid Hull Inflatables for commercial and recreational use.

He has worked for the IYRU in London as a Technical officer drafting and revising Class Rules for International yacht racing classes and giving technical support at 1992 Olympics. He has worked as a CEN Consultant Brussels providing relevant advice to ISO TC188 technical committees developing standards supporting the RCD, in particular ISO 12215 structural standards and ISO 12217 stability standards, emission standards and navigation light standard. Mr Handley had worked for Motorboat & Yachting testing craft and writing technical reports. He is a keen restorer of classic cars and boat. He has restored an early National 12 based on the Uffa King design that he still owns. This is a classic, solid plank, clinker craft. Essentially, he works with CAD/CAM 3D design software and naval architecture software.

Could the investigators have asked for any greater experience or expertise from a Naval Architect?

The familiarity with specialist computer software was about to become of primary importance, because the ship that was to be constructed had to be defined using modern methods. The use of computers and what can be produced on them needs to be understood, for a working method for the ship build had to be considered.

 

Computer Drawings?

Operator Experience

In current times, to manipulate the hull lines of any craft usually implies using computers running software such as Maxsurf or Rhino. There are other programmes. These programmes are not quite the magic solution that those who do not use them, might believe them to be. They do not automatically speak the truth, they just manipulate numbers. The numbers they manipulate are the numbers that are entered into them, so the person (or people) loading the information is the key to their performance, not the software or the hardware.

                As with all computer design/construction work, when the computer produces a solution it is up to the operator to understand that result. The operator needs experience to evaluate the quality and implications of what the computer is indicating. Throughout the process of loading data, then manipulating that data, the operator has to make many judgements and each one of these will impact on the final result. It is the quality of the questions that are being asked that will determine the end result, rather than the computer itself. The information being loaded might begin as well defined figures, but gradually choices and judgements will have to be made. Eventually, the process comes to depend on the experienced operator using the machine as a tool to explore and provide understandings. The skill is more in the artistic judgements based on experience, than in mathematical certainty.

Judgement criteria

When any drawings were made for the Mound 1, Sutton Hoo ship it was important to know:

  • who made them
  • where the original information came from
  • what process was used

It is this information that allows anyone looking at any drawings that are produced, to evaluate their quality.

If was suggested that the ship drawings might be commissioned from Denmark, but it was not the country, but the people, their experience and skill that was being referred to. It can be understood that if drawings were produced in Denmark for the ship construction, they would have found a high degree of academic acceptance. However, the essential knowledge gained in making the drawings would then be in Denmark, not where that knowledge was needed, was being referenced and applied, in England. The skills were available to make the decisions in England.

Questions

It was important that those who ran the project in England were party to the computer-drawing process. This meant that they could formulate the relevant questions to be asked and by working with a skilled, experienced boat/ship designer/naval architect, conversant with the software systems being used, could understand the implications of any judgements being made when entering criteria into the computer. This small group could then evaluate the computer answers to questions and could modify the input to determine what differences were made by changing figures on any sliding scale of value.

Some considerations

There were three major areas of interest where computer information would be of great value:

  • hull form, comparing the 1939 and 1973 drawings and understanding the choices made by Mudie’s team in producing their lines as they modified the 1939 information. This would furnish information on draft, weight, etc.
  • rocker, whether there would be a significant alteration in performance (stability, speed etc.) with different degrees of rocker, which is the downward curvature of the bottom of the hull
  • timber shrinkage, implications of timber movement:
  • i) allowances to be made during construction for green timber drying
  • ii) attaching individual planks to frames

There were other issues that could follow that would benefit from analysis once the core information was loaded. In the early stages it was not necessary to develop the shape of the planks until there was a better understanding of the hull form.

Marine Computer expertise in Britain

Possibly one of the most prestigious institutions with expertise in ship science and nautical studies is the Wolfson Unit at Southampton University (see: wumtia.soton.ac.uk). Paul Handley had studied Naval Architecture at Southampton University and on graduating began work at the University’s Wolfson Unit where he was involved in yacht stability research and tank testing boats. He was commissioned to:

  • establish the fundamental form of the Mound 1 ship by reviewing the available information
  • load it to relevant computer software systems
  • manipulate it to answer any questions that the construction committee might have. He would be available for direct discussion and consultation.

It was the intention of the Ship’s Company, the organisation in charge of the ship build, to relay findings and decisions to those with expertise in Denmark and also to discuss them with shipbuilders in England who could form an umbrella organisation overseeing the ship build at the appropriate time.

Drawings. Calculations. Predictions.

Until this time there has been a vague understanding that computer drawings or analysis would be needed, but these factors had not been defined. In conjunction with Paul Handley it was determined that the following list of actions would provide a foundation for the initial information required which could be taken in stages, as below:

Create hull shape computer model

This would depend upon: level of accuracy/extent of research

Involve comparison of available drawings to quantify the differences and understand how these differences came about

Create a unified lines plan

Take a first look at Hydrostatics, Stability, and effects of rocker etc. 

Later.

Create accurate planking runs after defining overlaps, timber thickness, dimension to inside/outside planks, allowance for shrinkage

Re-do hydrostatics.