GB2440319A

GB2440319A - Collapsible boat formed from releasably connected laminar panels

Info

Publication number: GB2440319A
Application number: GB0612430A
Authority: GB
Inventors: Matteo Signorini
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-06-22
Filing date: 2006-06-22
Publication date: 2008-01-30
Anticipated expiration: 2026-06-22
Also published as: EP2035272A2; WO2007147621A2; WO2007147621A3; ATE555003T1; EP2035272B1; US20120073491A1; GB0612430D0; GB2440319B

Abstract

A floating vessel comprising, in the orientation of use, a central longitudinal member 2 having a vertical height, and to each side of the longitudinal member, an upper substantially laminar panel 3 connected to the longitudinal member and extending outwardly therefrom. The vessel further comprising a lower substantially laminar panel 4 connected to the longitudinal member at a distance below the upper panel and extending outwardly from the longitudinal member. The outermost edges of the upper and lower panels are connected and the lower panel is larger in the outward direction than the upper panel. The panels may be releasably connected by means of hook and loop fasteners and may be formed of cellular or corrugated plastics material. The longitudinal member may comprise an aluminium beam.

Description

Origami boat

Table of contents

Executive Summary I I

Introduction I I

Research I 2 Product Development I 4 Proposed design 114 Acknowledgments I 15 Market research I Appendix A Other concepts I Appendix B Hydrostatic calculations I Appendix C Project Fireye' I Appendix D Project B+patient' I Appendix E Video fi rst sailing test I CD-ROM

Executive Summary

Water sports are popular outdoor activities. In the recent years new sports such as windsurfing and kite boarding are growing in popularity, compared to traditional sailing. They off er more fun and are more accessible in terms of money and space. The proposed product is a small boat, designed for leisure sailing and compatible with conventional sailing rigs (windsurf). The main : features are the portability and the accessibility that aim to attract new enthusiasts to the boating sports. When needed, it folds to a ft at pack with the dimension of windsurfi ng equipment. From the industrial design point of view the . : key factor of this project is the application of corrugated extruded polypropylene * sheet to boat building, using its properties to perform more functions. The folded sheets are at ones the boat skin and the structure; they form the living hinges and generate embedded reserve safety buoyancy.

** Origami boat (Figure 1) * S.....

S Introduction

Background

I have a passion for sailing. I have been on boats since a I was a child and I now enjoy dinghy sailing every now and then. I have always wanted to design a boat and that's as easy as it sounds the reason for doing this project.

Based on personal experience and informal exploration with sailors I focused my attention to small recreational sailboats for one person. This segment represents an important slice of the boating market and ranges from easy leisure boats to racing sail crafts. The common needs expressed by users during the early informal exploration are portability and easy of use. Hence the initial brief.

Initial Brief: Sailing fun in a bag "Create a new sailing experience that enhances the fun of sailing given by the interactions with the elements wind and water and that reduces the hassle associated with assembling, transporting and storing the equipment." Brief development The open brief allowed me to investigate in the early stages new forms of sailing and generate hybrid concepts, given in Appendix. The choice has been then for a craft that sails like a conventional dinghy but off ers more portability and accessibility for new sailors. Since Part 1 the project has been focusing on the boat hull which is the real bulky part of the boat. Moreover the compatibility with existing collapsible sailing rigs, like the windsurl ones, lowers the cost barrier for new users.

Research Markets overview User perspective

Conclusions (product brief)

Market overview Target user Nowadays the use of a foldable sailing boat responds to very specialized needs.

Most foldable boats are designed for fi shing, kayak traveling or as emergency dinghies. Some of them have optional sailing rig off ered by third parties. A new product needs to be placed in a wider scenario of water and recreational outdoor sports.

Direct competition and alternative products Direct competitors are very few collapsible sailing boats and foldable kayaks with custom sailing rig. Major examples collapsible sailing crafts are the Acquaglide: infi atable multi-sport craft deriving from windsurfi ng (retail price 350), the Stowaway plywood sailing dinghy (E1,000-2,000) and the Tinker infi atable with sailing kit (2,500-3,000). Foldable kayaks are quite popular and their price range is 1,000-E2,500. Small companies off er custom sailing kit for the most popular kayaks (500-1,000). The kit comprises boat appendices because of the poor kayak's sailing performances. The most common folding rowboats, mainly used for fi shing or as emergency dinghies are probably the polypropylene Portabote (from 1,300) and the aluminium Instaboat (E800). For the fi rst one it is now available a optional sail rig for 600. Finally an entry level sport sailing dinghy has retail prices starting from 1,675 (Topaz Taz), while the best-selling (Laser, over 190,000 units worldwide) is 3,500.

A sailing boat market overview is in Appendix.

Target markets The markets where collapsible sailing boat could compete are: 1. traditional sailing dinghies, by generating an affordable entry level solution, which adds ease of transport and storage.

2. windsurfing, by sharing same sails and making the switch from one sport to another less expensive.

3. infi atables, by means of providing an easier and quicker assembling system 4. outdoor "week-end" sports and leisure activities such as skiing, snowboarding, mountainbiking, kayaking, thus winning more enthusiasts to the boating sports.

Portabote (Figure 2) Aquaglide (Figure 3) foldable kayak with Batwing (Figure 4) User perspective Sailing practice and user profiles Mapping the practice of sailing around the targeted use of the boat, we observe that new alternative water sports such as windsurfi ng and kite surfi ng are getting more popular and are relatively less expensive than traditional sailing.

On the other hand these alternative sports have higher access barrier, consisting of training time to learn how to windsurf and kite board. This is the major USP of leisure boats such as rotomoulded catamarans (e.g. Funboat by Laser or Bravo by Hobie) which ensure higher stability and have easy boomless rigs.

Portability issues : Existing boats need to be transported on a trailer or the on the top of the car. In * this case is diffi cult to one person to lift it over the top (weight over 50kg). On the other hand windsurf equipment can be transported on top or in the car and one * person can load and unload it. Furthermore windsuris can be carried on the plane, while that is impossible for boats.

Mapping the sailing users profiles with the equipment they use. The target spot for the new product is marked with the empty circle. (Figure 5)

Research conclusions

Business scenario for the product development Target user First boat for young people, leisure boat for families, new sail enthusiasts Price Price range much lower than traditional boats and therefore comparable with other popular recreational sport equipment such a high end mountain bike and or a skiing set.

Market entry strategy To enter the target markets the strategy could be to off er a boat compatible with existing sailing rigs, thus lowering the price barrier to access for existing sailors and new corners.

This would also lower the barrier regarding acceptability and feasibility, with possibility of partnering with existing known sail brands for delivering complete boats over their distribution channels.

Product specifications

Crew: I adult person, avarage weight 75kg Sailing performance comparable to beginner sailing dinghies such as Topper Taz or Laser Pico Compact dimensions when folded for car transportation, comparable with windsurli ng equipment (Weight 25Kg, Length 3m, "fi at pack") Compatible with existing sailing rigs (e.g. windsurfing sails) * * * * **

S

S.....

Development Concept Methodology Hull design Folding Pattern Material and process Detail design Rig design Testing Concept Design directions The idea generation have been visualised based on the issue of deployability, The different design directions give life to groups of ideas which can be often combined to create new ones. Figure 6.

Concepts not taken forward are collected in Appendix Chosen concept origami boat' The boat is made out a folded lightweight plastic sheet,; e.g. sealed corrugated extruded sheets, since they provide rigidity and high bouyancy.

In the fold up configuration (sailing) it forms a hollow body, rigid enough to hold one passanger. In the closed position (transport) is a fi at pack' of folded panels, which store inside the other parts (rudder, centerboard and sail rig).

(Illustrations in figures 7 and 8) Concept Origami boat Figures 7 and 8 Methodology The development of the concept has been carried out by dividing the design work in packages and reiterating the following design steps: * . Hut! design (shape the boat in the water) Folding patterns (geometry studies to convert 2D in 3D) Deck design (design the space for the crew) Material and process * a. a..

* Detail design (fixing, sealing solutions) Rig definition Pmtotyping Each step requires research, concept drawing, sketch modelling and testing, and reiterating the results over the other work areas. For ease of reading, in this report the results of each area are presented sequentially and in duff erent chapters, which does not refl ects the iterative nature of the design project! In each chapter it is referred to the proposed design, please browse ahead for reference. (Figure 9) Hull design Form generation The idea of folding flat panels to obtain the three-dimensional hull shape suggests that the boat is going to have a polygonal surface, a "mesh" of fI at or curved faces. Several methods for generating hull shapes have been considered: Wrapping: using a fI exible sheet and bending or wrap it in order to fi nd a stable con-fi guration (fi xed in the minimum number of points). This method generates curved surfaces, but is quite hard to model on software, because of the important role played by the material elasticity. Thermoforming sheets has been used to sketch models.

Meshing: starting with a traditional curved hull surface, is it possible to mesh it on software packages to polygonal surfaces with small number of faces. The diffi cult of controlling the mesh generator on the tested software makes it diffi cult to obtain desired foldability and rigidity.

Geometrical assembly: as the opposite of meshing, it is possible to build polygonal surface from scratch by adding polygons to simple shapes. In this way it is possible to control the geometry and keeping the foldability of the hull. 3D software packages allow to generate quickly many shapes, which have been easily visualised with paper models.

With the last method a classification of possible polygonal surfaces, according to simple parameters as number of sides on the plan and on the main section. By : ... increasing the number of sides the hull come closer to the traditional curved hull, thus improving the performance but making the folding and structural issues more complex.

original hull of a typical modern sailing yacht (Figure 10) : polygon mesh with 6 polygons (Figure 11) * polygon mesh with 8 polygons (Figure 12) polygon mesh with 2 polygons (Figure 13) *....: Classification of polygonal hull shapes according to number of sides on the * main section and on the deck. The number of faces increases therefore moving down and right. (Figure 14) Hull design Naval architecture The hull shapes have to satisfy basic parameters to be considered for a boat.

With the help of naval architecture texts and experts, I compiled a list of the primary criteria to analyze a sailing vessel: Structural rigidity, especially longitudinal rigidity. The boat does not have to bend by eff ect of compression between water and crew weight.

Buoyancy: besides keeping afloat the crew without drafting too much, the boat needs to have reserve buoyancy for safety reasons. Positive flotation is the property to fl oat when filled with water (e.g. after capsize), and is normally achieved with extra fi oating bodies (e.g. foam) attached to the boat.

Stability especially transversal stability is important for sail boats. The boat needs to generate a righting moment when heeled on the side. For small dinghies without a keel, this is anyway not enough to withstand the force of the wind on the sail and the position of the crew is crucial to keep the boat upright. Nevertheless stability is also comfort: not heeling excessively when the crew moves from centre to side, is also much appreciated.

Drag: the resistance to the motion in the water is mainly given by the friction of the water on the boat, and it is proportional to the wetted surface. The second main component is given by and the generation of waves.

Plane: the capacity of the boat to generate a vertical lift by the fI ow of the water under the hull depends on the hull geometry. If so the boat rises from water at speed (plane) and reduces the resistance to motion. This hydrodynamic eff ect is quite complicate to calculate also with software and is generally tested in water with models. Generally the fi atter the hull, the more the lift it generates.

"Sailability" or behaviour of the vessel in the sea in duff erent conditions; e.g. sea-The first four criteria can be predicted with calculations based on the hull geometry and have been analyzed for the generated hull shapes. A professional software (Rhinomarine by Proteus Engineering) has been used for the calculations. The results of the comparison of the different shapes are given in the diagrams in Appendix. They do not exclude any of the shapes nor do they give us a clear winner. They confirm the intuition that increasing the number of sides, the performances increase as we have more parameters to adjust. The choice of the shape is then a trade-off between hull design and the other design * areas, where these naval architecture criteria have also been considered. *SSS * *

In Appendix the hydrostatic parameters for the proposed design have been also calculated and following these results, we can make following considerations.

Structural rigidity: The boat is designed for a displacement of 125 kg, i.e. the weight of a person (75kg) plus the boat and eventual equipment. The pressure on the hull is therefore 125 kg over the wetted surface (about 2m2), which in duff erent sailing conditions may reduce up to 50% (boat on a wave or on the plane): therefore 125 Kg/m2.

Buoyancy: The twin-walled plastic sheet is extremely buoyant and gives the boat an embedded safety reserve buoyancy, able to hold a person afloat in the case the boat should open up in water. The boat is made of about 10 m2 of empty sheet: with an average thickness of 6mm weight of 1 kg/ m2, the material account for a positive flotation of 50kg, enough to hold the equipment (mast) and support the person afloat.

When folded up, the boat generates an enclosed volume of about 300 litres, which gives an displacement for 300 kg, useful for safe navigation on waves, when water may fill up the deck.

Stability In the diagram the stability curve of the boat has been compared with the top-selling sailing dinghy (Laser) which is 50% bigger in volume, calculated with the same software. The curve shows a positive righting arm up to a heel angle of about 80 degrees.

The theory is comforted by the test on the prototype, as shown in the picture.

Laser (figure 16) Origami boat (figure 17) Folding patterns Structure Since the fi rst paper models it has been clear that the folding plays the important role for the structural strength. A constant rule for the generation of folds, has been the utilization of triangular faces, in order to create only volumes composed : ... by a number of tetrahedrons, to maximize the structural stability of the shape and do not rely only on the rigidity of the material. This approach guides the choice of the hull shape towards those ones with the least number of sides. The chosen shape defi ned Al in the previous classification, is composed of two symmetrical . .: tetrahedrons joint in the middle. More complicated shapes require dividing up the volume in more tetrahedrons and requiring more material, which has to fold then * to a fi at pack of minimal dimension.

In order to maximize the longitudinal rigidity no bends have been made on the longitudinal dimension. The boats folds up as a book, with the spine on the * length.

Table of possible folding configurations (figure 18) Transom Important structural element of the boat is the transom. Different are the possibilities offered by the fold: double bottom: elegant and effi dent solution, that challanges the folding in order to achieve necessary rigidity and sealing.

solid transom (inserted panel): easy and structurrally sound solution, adds an extra part to be carried and stored in the boat. This solution has been used in the sailing test rig.

solid transom (folded up): the sheet folds on the back as they fold on the front.

This is the solution chosen for the proposed design. Deck

After the water test of the test rig the deck has been redesigned. The crew on a sailing boat has to change position quite often and be able, especially on small dinghies, to sit anywhere in order to balance the boat. While a fi at and slightly concave deck is actually quite appropriate for the latter purpose, it is quite uncomfortable for the legs, imposing the person to knee rather than sit.

The final design has been added a raised border on the sides, to allow the passenger to sit on it. The border is an additional small tetrahedron with many functions. Besides forming a seat for the crew and something to hold on, it adds rigidity to the side. Most important function it joins the two sheets and forms the sealing.

Compared to the test rig configuration, the fi nal design has two sheets of corrugated plastic, fixed in the middle to the central frame. (See figure 19) This configuration besides allowing the raised side border, allows also to use material of different thicknesses and to orient the corrugations of the two sheets in different directions, to increase the stability.

Three possible 2-sheet configurations (figure 19) * * Material and process Considered materials Materials suitable for this application are: Correx (or Corriboard), i.e. multi-walled extruded polypropylene sheets, often used for signs, packaging or construction.

Corrugated polycarbonate sheets, which are available in a wider range of thicknesses and rigidity and often used for clear roofing.

Plain polypropilene sheets CURV (woven polypropylene) sheets Aluminium sheets joint with rubber or neoprene hinges The choice for Correx has been guided by the idea of realizing many functions in one part. The sheets act as skin of the boat, have structural properties given by the rigidity of the corrugation, work as living hinges and when sealed on the edges they assure an extra buoyancy, very useful for a boat. With any other solution an additional material should have been introduced to realize those functions: i.e. a foam insert on the plain sheets to increase buoyancy.

Material thickness Correx is commercially available with a thickness range from 2mm to 10mm, with duff erent grades. The test rig has bin made out of 10mm twin-walled polycarbonate sheet, proving to be rigid enough. The two sheets included in the proposed design can have different thicknesses, being the internal one lighter.

Rigidity depends mostly on the thickness of the single layers or Walls of the sheet profile. The right choice has to be done after building full scale prototypes with sheets in the 6mm to 10mm range.

The availability and the price on the market of this material is one of its advantages.

If the boat would be produced on large scale, it might be possible to develop a custom extrusion. In that case the external layer should be thicker to increase the resistance to abrasion, The cells should have a triangular profile, which increases stability and makes easier scoring the folding lines.

Edge sealing for the sailing test rig (figures 20 and 21) Hinges Different solutions have been investigated to create the folding lines. In the figures three examples are illusrtated. The choice has fallen for profile rolling S....' because it does not require bonding of material to polypropylene, which is possible only through welding (no adhesive are available for polypropylene) and therefore difficult for large surfaces.

To score the folding lines on the corrugated sheets, different tools and combinations of process parameters have been tested (i.e. temperature of material and tool, pressure and speed). In the figures there are some of the results of these tests. The most successful process has been realized with a custom made tool, that resembles an industrial pizza-cutter and prototypes a manual profile rolling. The material has been heated close to melting temperature and a cold tool has achieved better surface finishes.

Profi le rolling allows furthermore to create curved hinges. These are quite important aesthetic features for the final design, as well as they allows to create curved surfaces.

profile rolling (figure 22) material removal (figure 23) bonded layers (figure 24) Unsuccessful tests: different combinations of material and pressing rod temperatures (figure 25) Seccessful tests with custom tool (figure 26) Detail design Central frame The central frame has been introduced to add longitudinal rigidity to the boat and provide a structural element where all the equipment can be fixed: mast, centreboard, rudder, mainsheet and foot straps for the crew.

Materials that have been considered are: injection mould, pultrusion, aluminium extrusion, PVC extrusion, composite and fibreglass (GRP).

While the injection mould tends to be to expensive and technically diffi cult for this length, the pultrusion does not work well in torsion. The PVC extrusion has been used for the test rig and had to be reinforced to achieve suffi cient rigidity.

Aluminium extrusions can be realised in custom profiles, which would allow a better fi xing of the Correx sheets. It would be realised as the aluminium spars, which are the most common material for actual sailing masts.

Fixing and sealing : ... The edges of the external Correx sheet are welded at the bow and stern, in order to realize a closed surface in contact with water. External and internal sheet are fi xed to the central frame. The external edges of the two sheets fold on themselves realizing the seal to water, when rubber sealing strips are provided on the contact surfaces.

* Several possibilities have been considered for the fi xing of the fold: buttons, *. : straps, bolts and Velcro. The last possibility has many benefi ts: lightweight, easy * to open and close, invisible. Industrial types of Velcro are available with high strength. Especially the moulded tapes, with symmetric "mushrooms" sides.

These plastic tapes can be glued or better welded to the polypropylene sheets.

The symmetric tapes can used both for fixing the boat in the fold up confi guration as well as fi at pack.

An alternative to seal solution is an inflatable chamber inside the enclosed volume between the sheets. Such a chamber, realized in thin elastic material which folds on one of the sheets when closed, would solve completely the sealing -12 -problem, occupying the volume with air and giving extra rigidity to the structure.

This solution has not been integrated so far to simplify the assembly process for the user and avoid pumping.

Fixing and sealing solution for the ext. edges (figure 27) Rig design The design of a foldable sailing rig was included in the initial concept and duff erent confi gurations have been considered. On the other side, masts in sections are quite collapsible and I decided to focus on the hull, which is the real volume to collapse, as result of this project.

On the other the idea of fitting commercially available rigs from other boats and especially from windsurfs has many benefits.

Wider range: windsurf sails are available in wide range of sizes to match the wind conditions. Similar concept could fit this lightweight boat.

Weight: windsurf rigs are lighter, because using fi bre masts and that is essential for this lightweight boat.

Business model: attractive commercial strategy to enter the market with lower barrier: entry level customers do not need to buy a sail, but can reuse old ones.

Windsurfers can have a low cost switch to sailing for a day or for the family.

Custom sail could always be offered as optional.

windsuri like rig (boomless). E.g. batwing' sail for kayak (figure 28) :*. Lateen sail (boomless), with front mast supports (figure 29) rigid wing (more efficient, smaller size) (figure 30) Lateen sail (boomless), with back mast supports (figure 31) traditional mast/boom rig. E.g. Topper (figure 32) foldable rigid sail (in sections) Same material as the hull (figure 33) Prototyping During the whole process models and prototypes have been used: Paper models -13-Polypropylene and correx scale models: to test the folds with thicker and harder material and to test in water.

RC model: the fi rst sailing of the proposed hull shape has been realized with a radio controlled model with a polypropylene hull in scale 1:5.

Full-size cardboard model The model have been used as test rig for the folding / unfolding process. The model showed how easy the folding could be and give an idea of the handling of boat in real size. Focusing on the fi xing, this prototype inspired the idea of welding toghether the sheet edges at bow and stern; so that they are automatically in place during the opening/closing process. The idea of embedded handles for easy transportation came also from this test rig.

Polypropylene model (figure 34) RC model (figure 35) full size cardboard model (figure 36) Full-size sailing test rig It is made out of seoparate corrugated polycarbonate roofing sheets. The frame is obtained welding PVC square tubes and the hinges are realised with PVC tubes fixed to the sheets with fibreglass reinforced tape and hinged on a aluminium rod.

The sailing rig and equipment is borrowed from a Topper dinghy and the weight of the mast has imposed an metal reinforce on the PVC frame. The sealing has been obtained by taping the hinges, thus partially restricting the unfolding process. The total weight of the boat is 27 kg and has been tested with success in water (see attached DVD with sailing video!) First sailing test with a topper sailing rig (figure 37)

S

view of the panels (figure 38) * ..* inserting the aluminium rod in the hinge (figure 39)

SI I * ** * SI

Mock up (figure 40) this model has been made out of corrugated polypropylene sheets and *. : cardboard, to simulate the folding process.

* Othermain features are: Improved deck design with raised borders (1) velcro fasteners (2) curved hinges (3) two corrugated sheets with corrugation in different direction for added rigidity (4) -14-Proposed design Style How it looks How it works Parts and manufacturing Technical drawings Style Mood board polygon mesh' (figure 41) How it looks (figure 42) How it works Figure 43 1. fold up 2. open sides 3. open back 4. insert spars and close internal sheet 5. close external sheet 6. fI at pack Parts and manufacturing :..::: Dimensions a...

fold up: 2.8m x I.55m x O.35m fi at pack: 2.98m x O.90m x O.lOm *. .: weight: 25 kg *: Parts and manufacturing Figure 44 Polypropylene sheets : Twinwall extruded polypropylene sheet, cutted and scored (profi le rolling) to form * the folding lines.

Edge sealing and welding The material weights 15kg and the required quantity (10 m2) costs on the market about 60. Frame

Aluminium extrusion machined to realise the fitting to the other parts -15-Supports (mast, centreboard, rudder) Injection moulded parts FastenersIndustrial moulded velcro" tape (welded on the polypropylene sheets) Acknowledgements The project would not have gone so far and not been so enjoyable without the kind support of: Tristan Smith and Tim McDonald, Research Assistants at the Naval Architecture Department of UCL Rob Swindell, Naval Architect, Bureau Veritas (insurance company) Mark Mellors, Aerospace design engineer, expert sailor & hydrofoil designer Prof. Pat Leevers, Mechanical Engineering, Imperial College, expert in polymers Joe, sport centre manager, and the Imperial College swimming pool Neil, sail instructor, and the Hillingdon Outdoor Activity Centre IDE "sailing tutors" (Roger, Mark and Miles) Appendix A Market research compact sailing crafts Collapsible sailing boats Kontenderby Stowaway (figure 45) Length 3.05m x Beam 1.36m Length (folded) 3.15m Width (folded) 0.56m Depth (folded) 13 cm Sail area 5.67sq.m * Weight of hull 36kg Thwarts and Sail Kit 25kg * * Tinker by Henshaw Inflatables Ltd (figure 46)

Technical Specification

****** * Dimensions overall 3.15m x 1.50m Folded dimensions 110 x 62 x 23cm Hull weight 24kg (52.9lbs), Sailing kit weight 14kg (3llbs Price 2,800 Aquaglide Multisport by Mistral (figure 47) -16 -It is a inflatable windsurf board, hugely dimensioned for extra stability and can be used as conventional windsurf, as sailing boat with the same rig, as rowing boat and for towing. The boat has success in the USA and costs 350.

Other collapsible boats Portabote (figure 48) Length/LOA 8ft 9" (2.85m) Folded Thickness 4 in. (11.4cm) Folded Width 24in. (59cm) Width (Beam) When Open 56in. (1.42m) Draft 4in. (11.4cm) Depth midship 22in (52cm) Hull weight (less seats/transom) 47 lbs. (21.kg) Instaboat (figure 49) Length 3.25 m -1 0'8" (Folded) 3.45 m -11'4" Width 1.12 m -44" (Folded) 16cm -6,5" Depth 33 cm -13.5" (Folded) 38 cm -15" Weight 30 kg -66 pounds Supported weight 204 kg -450 pounds figure 50) Folbot folding kayak with Batwing by BSD (figure 50) Kayak Specifi cations Length: 17' x Beam: 34" x Height: 16" Weight: 62 lbs.

Sail kit specifi cations Sail: 30 square foot reinforced Dacron.

Pontoons (Outriggers): Snap on, orally inflatable. Urethane bladder in nylon shell.

Bag dimensions: 14" x 6" x 53" (no mast) Sailing dinghies entry level I teenager Topaz Taz (figure 51) Manufacturer Topper Sailboats : *** Length 2.95m, Beam I.20m, Hull weight 40kg Construction TRILAM Polyethylene (rotomoulded), Moulded Foils, Anodised Aluminium Spars Sail Area 5.39 m2 (Main 4.39 m2, Jib 1.00 m2) . Crew 1-2, Cartoppable *: Pricefromfl775, new boats in UK in 2005 Topper(figure52) * Manufacturer Topper Sailboats Length 3.40 m, Beam 1.20 m, Hull weight 43 kg Sail Area 5.20 m2 Construction Polypropylene, Mouded foils and coated alum mast and boom Racing Crew 1, Cartoppable Price from 2395 1,000 new boats in UK in 2005 Pico (figure 53) -17-Manufacturer Laser Length 3.50m, Beam 1.43m, Draft 0.82m Mast Height 5.83m, Sail Area 5.10 m2 Hull Weight 60 kg Construction Techcrothene 109 Crew 1-2 Price from 2325 Sailing dinghies Leisure catamarans Funboat (figure 54) Manufacturer Laser Sailing Crew: I Length: 3.9 m Beam: 1.25 m Sail Area: 4.8 sq m Price 1,845 Hobie Bravo (figure 55) Manufacturer Hobie Length 12', Beam 53", Weigth 195 lbs.

Mast Length 19', Sail Area 86 sq.ft.

Construction Roto-Molded Polyethylene Sailing dinghies the smallest! Optimist (figure 56) Singlehander for under 16s Several manufacturers (e.g. Ace, LDC, Devoti) Construction GRP (older versions in wood) Length 2.30 m, Beam 1.13m, Hull Weight 35 Kg Sail Area 3.59 m2 (main) Crew 1 (up to 45 Kg) Price * S ill newboatsin UKin 2005 Zoom 8 (figure 57) Sin glehander ideal for teenagers * Manufacturer Trident UK ****** * 1 Length 2.65m, Beam 1.45 m, Hull Weight 35 Kg Sail Area 4.8 m2 (main) Crew I(max 65 Kg) *....: Construction GRP * Price Escape 9 (figure 58) Doublehanded cruiser-racer Manufacturer Johnson Watersports Length 2.9m, Beam 1.2 m, Hull Weight 38 Kg Sail Area 5.2 m2 (main) Crew 1-2 (max 140 Kg) Construction Polyethilene Price Sailing dinghies top selling I top racing Laser (figure 59) Manufacturer Laser Sailing Length 4.23 m, Beam 1.42 m, Hull weight 59 Kg Sail Area 7.06 m2 (or 5.7, or 4.7) Crew 1 Price from 3,550 3,792 new boats in UK in 2005 most ever selling boat: 190,000 boats olympic class Topaz System (figure 60) Length 3.86 m, Beam 1.45 m, Hull weight 60 Kg Sail Area 5.64 + 1.09 m2 Crew I Construction Polyethlene 1,000 new boats in UK in 2005 RS 600 (figure 61) Manufacturer RS Length 4.47 m, Beam 1.93 m, Hull weight 52 Kg Sail Area 12.14 m2 Crew 1 Construction GRP high speed boat Windsurfing RS:X (figure 62) : Onedesign Olympic windsurfi ng class * *** Manufacturer Neil Pride .. Length 2.86m, Width 0.93m, Volume 2201 S...

Hull Weight 14 Kg *. * Sail8.5-9.5m2 . .: Total weight *:* Construction carbon sandwich Starboard GO (figure 63) * : popular recreational, modern short-board * Manufacturer Starboard * : * Length 2.50-2.56m, Width 0.53-0.68m, Vol 139-1851, Hull Weight 10-12Kg Sail 5-12 m2 Appendix B -19-Other concepts (not taken forward) Concept overview inflatable catamaran (figure 64) Pros High deployability (catamaran can have considerable size) Safe Potential sail performances Easy sailing Contras Mast rigidity Resources required to produce pressurized bodies origami boat (figure 65) Pros Extreme elevate buoancy Potentially low cost Intuitive! known assembly Unconventional boat design Resources required for prototyping Contras Hinges and sealing Sailing performances kite watersiedge (figure 66) Pros Very compact Potential high speed and jumps * * Aspirational sport Contras Requires training *:*. Scaring for beginners * *****.

* wearable hydrofoil (figure 67) *. : Pros * Extreme compact Potential high speed and jumps Aspirational sport Contras Requires training Scaring for beginners -20 -Inflatable Cat (figure 68)

Infi atable mast

mast + hull kite shaped sail Kite sledge (figure 69) Kite powered Inflatable + foldable "sledge" Wearable hydrofoil (figure 70) Kite powered Wearable wing (hydrofoil) Appendix C Hydrostatic calculations Hull shapes considered forn comparison (figure 71) Comparison of shapes Stability (figure 72) Comparison of dimension *::::* Stability (figure 73) * . Proposed design hydrostatic parameters (1) (figure 74) * S * Proposed design * hydrostatic parameters (2) (figure 75) Proposed design hydrostatic parameters (3) (figure 76) -21 -Displacement: with a draft of 10 cm, the boat holds over 100kg ofweight.

the body has a displacement of over 300 kg Proposed design hydrostatic parameters (4) (figure 77) Proposed design hydrostatic parameters (5) (figure 78) stability chart the boat has a positive righting moment (i.e. tends to return upright) up to a heel angle of around 80 degrees.

The curve is calculated for a initial draft of 10 cm and a weight of 100kg (in the middle of the boat) 0S * * * S.. *.* * S S... *. I * * . * *. * S S* I * S S * .*

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*S*.SS * S

Claims

Claims I. A floating vessel comprising, in the orientation of use, a

central longitudinal member having a vertical height, and to each side of the longitudinal member, an upper substantially laminar panel connected to the longitudinal member and extending outwardly therefrom and a lower substantially laminar panel connected to the longitudinal member at a distance below the upper panel and extending outwardly from the longitudinal member, wherein the outermost edges of the upper and lower panels are connected and the lower panel is larger in the outward direction than the upper panel such that the panels form a stable structure.

2. A floating vessel as claimed in claim 1, wherein the outermost edges of the panels are releasably connected.

3. A floating vessel as claimed in claim 1 or 2, wherein the panels are releasably connected to the longitudinal member.

4. A floating vessel as claimed in claim 2 or 3, wherein the panels are releasably connected with hook and loop fasteners.

5. A floating vessel as claimed in any preceding claim, wherein the panels are formed of cellular or corrugated plastics material.

6. A floating vessel as claimed in claim 5, wherein the corrugations or cells of the upper panel run transversely to the corrugations or cells of the lower panels.

7. A floating vessel as claimed in any preceding claim, wherein the longitudinal member comprises an aluminium beam.

8. A floating vessel as claimed in any preceding claim, wherein the vessel is a boat.

9. A boat substantially as hereinbefore described.