Polycore – the Stronger Polypropylene HoneycombPolycore is one of the world’s leading suppliers of thermoplastic polypropylene honeycomb and lightweight composite solutions.

Polycore Polypropylene Honeycomb is the next-generation polypropylene honeycomb that is the strongest on the market today. With its all-round superior properties and competitive pricing, it is fast becoming a popular composite core material for increasing strength and stiffness at reduced weight.

Properties• Excellent strength-to-weight ratio• Large operating temperature range• Does not absorb water• Excellent corrosion resistance• Superior shock absorption and impact resistance• Superior fatigue resistance• Excellent sound insulation• Good thermal insulation• 100% recyclable• Easy to apply

ApplicationsCurrently, Polycore polypropylene honeycomb is being applied extensively in a diverse range of applications across many industries which include the Marine, Automotive & Rail, Wind Energy, Architectural, Industrial, Packaging, Signage and Recreational industries, etc.

Why PolycoreReasons why Polycore is the polypropylene honeycomb of choice:

• Strongest in the market• Thinnest in the market (at only 4mm)• Most technologically advanced (completely flat surfaces, low

resin wastage, strongly fused skins that do not delaminate)• Available in different grades of strength• ISO 9001:2000 certified• Currently undergoing certification by the major classification

societies• Endorsement by space agency

Polycore the Strength Lies Between

www.hexacor.com

“ When it comes to core materials of uncompromised strength, weight and performance, Polycore is the name to remember. ”

Technical Specifications

Properties Tests PP - 8 PP - 8H PP - 10

Cell Size 8 mm 8 mm 10 mm

0.3 “ 0.3 “ 0.4 “

Density ISO 84580.0 kg/m3 80.0 kg/m3 64.0 kg/m3

5.0 lb/ft2 5.0 lb/ft2 4.0 lb/ft2

Compressive Strength ISO 844

2.0 MPa 2.2 MPa 1.0 MPa

290 psi 319 psi 145 psi

Compressive Modulus ISO 844

95 MPa 97 MPa 50 MPa

13,779 psi 14,069 psi 7,252 psi

Shear Strength ISO 19220.6 MPa 0.8 MPa 0.3 MPa

87 psi 116 psi 41 psi

Shear Modulus ISO 192213 MPa 19 MPa 9 MPa

1,856 psi 2,756 psi 1,305 psi

Tensile Strength ASTM C297

0.7 MPa 0.75 MPa 0.7 MPa

102 psi 109 psi 102 psi

Operating Properties

Effective Temperature Range -30°C to 80°C-22°F to 176°F

Thermal Conductivity(at 10°C or 50°F) 0.102 W/mK

Sound Attenuation(50 to 4000 Hz) 22 dB

Water Absorption < 0.1%

Flammability(DIN 4102-1) Normal Inflammable (B2)

Product Dimensions

Thickness: 4mm to 500mm (0.16” to 20”) { Tolerance ± 0.2 mm (0.008”) }

Length and Width: 1150mm x 2300mm (3.75’ x 7.5’) 1220mm x 2135mm (4’ x 7’) 1220mm x 2440mm (4’ x 8’) { Tolerance ± 4 mm (0.16”) }

Other customs sheet sizes up to 3000mm x 1500mm (9.8’ x 4.9’) are available upon request.

IMPORTANT NOTICE: The information herein regarding our products, equipment and processes is believed to be reliable and to the best of our knowledge. We do not warrant the accuracy and completeness of any such information. Whether expressed or implied, including warranties of fitness for a particular purpose, it is the user’s or purchaser’s responsibility to undertake sufficient testing to verify the suitability of our products for their own particular purpose. The information contained herein shall not be construed as inducement, permission or recommendation to infringe upon any patent rights or other rights of third parties.

Polycore the Strength Lies Between

w w w . P o l y c o r e . c o m.au

a 14m amateur designed and built

Polycore™ powercat

50 MULTIHULL WORLD POWERCATS MULTIHULL WORLD POWERCATS 51

by J O D J U B A L

BUT BRUCE HODGENS HASdone it – and extremelysuccessfully. His beautifullybuilt cat which is to be ‘home’for him and his wife, Barbara

is nearing completion in Townsville withsplashdown scheduled for early March.

It’s always inspirational to see buildingprojects succeed – but even more sowhen the owner has jumped in the deepend as Bruce has and actually done itfrom scratch – with no outside helpwhatsoever – even wiring andspraypainting himself.

Liquid Assets is the culmination of alifetime of experiences that have allserved as building blocks towards thisultimate dream ...

An orange orchard in Waikerie, SAsounds an unlikely spot for a passion forthe water to develop but Bruce beganrowboat fishing and waterskiing as ayoungster on the Murray River. He gotinto surfing while at Teacher’s College butit wasn’t until he met fellow studentBarbara that sailing became an integralpart of the couples’ life. “Barbara hadalready begun sailing and introduced meto it. We bought a Rainbow and then a420 and although pretty inexperiencedbegan entering State and National Titles.We built a Fireball before we got marriedand spent our honeymoon at theNational Titles in Port Macquarie!”

After ‘bumming around Europe’ for awhile in 1976, the pair returned to Oz

50 MULTIHULL WORLD POWERCATS MULTIHULL WORLD POWERCATS 51

1. (main pic left)2. (above)

Designing and buildingyour own big powercat.The idea wouldnʼt seemso daunting in thehands of a professionaldesigner and/or builderbut for an ex-geography/marinestudies teacher, thenotion seems almostoutrageous.

ASSETS

my life – not only building and sellingthem but organising and competing inNorth Queensland, National and Statetitles. We attended the PNG Cup everyyear and also attended the NewCaledonia World Cup and the ThailandCup. It was a pretty good life for a whilethere, trooping around the placesailboarding!”

‘Trooping around the place’ earnedBruce some impressive places, including

and built another Fireball which theyenjoyed until the end of 1980 when anexchange teaching job in Calgary, Alberta,Canada called. It was here that thecouple got into windsurfing – in a big way.“We came back from Calgary and withinsix months I’d won my weight division inWinter State Titles,” Bruce said. “In 1984we moved to Townsville where thewarmer climate meant we could windsurfand sail all year round. I set up asailboarding business and for years it was

above from left:34 567. (below)

winning the 1988 Mistral World MastersDivision in Sydney along with theWindsurfer World Masters in 1990. Itwas almost inevitable that sailing wouldagain feature in his life and racingregularly on the trimaran Voodoo with abunch of other sailboarders soon sawBruce hooked on multis. In 1998 hebegan building his own SchionningWaterline 1160. “We launched the boatat the beginning of 2000 after one yearbuilding full time (took a year offteaching), and one year part time.” Thenext four years saw Bruce and Barbaraenjoying their cat, cruising and racing.They decided to sell that boat and build abigger cat to go extended cruising.However when they looked at the costof a bigger cat with diesels and sailing

gear the costs started to blow out. “Thestanding and running gear was going tocost $100,000 and you can buy a lot ofdiesel for that,” Bruce said. They alsofound that when cruising you often onlywent short distances when you movedand you had to run the engines to chargethe batteries etc so sails and rigging spentmost of their life rotting in the sun ...maybe a powercat was the answer ...

“I downloaded trial versions of severaldifferent boat graphics programs from theinternet, and found that Maxsurf was themost intuitive to use. However when Ifound out if cost $12,000 I figured I hadbetter find something cheaper.” Aprofessional boatbuilding friend said hehad a copy and kindly allowed Bruce touse it ... ideas for the next boat startedtaking shape.

MULTIHULL WORLD POWERCATS 3

“They decided tosell that boat and

build a bigger cat togo extendedcruising”

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“I spent a year learning how to driveMaxSurf and when I got to the finaldesign, it was about draft number 20!The program is fantastic – it totallymodels the whole boat and then you canpull each component out of the boatfrom MaxSurf and bring it up onAutoCad, dimension it all and then makeall the pieces.”

Bruce’s design criteria began with asimple premise. “I wanted to be able toput a standard house kitchen in the boat,along with dining table and chairs, setteeetc to avoid the cost and time of buildingit all in. I also wanted to achieve a fuelusage of one litre per nautical mile. Thefinal design was a 14m Waterline withlong skinny, deep hulls and a beam of

2 MULTIHULL WORLD POWERCATS

9

5.5m. It is more a traditional or classicdesign with walkways down the sidedecks, side opening doors and plenty ofopening windows. There is goodoverhang on both the side decks and the45° sloping windscreen to keep the sunand the water out.

“So far, there’s not much I’d change.Designing a boat yourself means you candesign with ease of construction in mindand also plan for all the systems such aswiring, plumbing and engine installationbefore you start. Having built boatsbefore I had an idea which aspects weregoing to be the most difficult so Idesigned the boat with flat panels abovethe knuckle.” The piece under the watercomes up to the knuckle (to deflect thewater) and was all done in strip cedarand epoxy. This enabled me to do threedimensional curves and keep a veryhydrodynamic shape under the water.The rest of the boat is constructed fromflat panels of high strength Polycore™ ofvarying thicknesses – 19ml skins, 25mlbulkheads, 30ml floor and roof withappropriate knitted fabrics and vinylester.I chose Polycore™ for a number ofreasons – and did seriously consider plyfor a while – but the benefits ofPolycore™ far outweighed other optionsfor cost, strength and integrity – no rotconcerns whatsoever! I started with 130sheets (in 19, 25 and 30mm) and beganmaking all the components such asbulkheads, bridgedeck floor, roof,furniture, decks, floors and all the upperhull skins. Basically, other than the hullsbelow the waterline all the boat is madefrom Polycore™ flat panels, some ofwhich are bent to 2D curves. I spentconsiderable time researching differentmaterials for the boat and now amconvinced that I chose the best product.I’ve saved approx $40,000 usingPolycore™ versus foam or balsa pre-made panels. As a backof envelope calculation a19mm panel ofPolycore™ costs $100,and then with one layerof 600 grams/metre2

knitted glass on eachside with vinylester resincosts about another $40.Pre-made balsa or foampanels cost in excess of$400. I know this

doesn’t take into account the labour tomake the panels, but you can sure get alot of panels made for $40,000 worth oflabour!

There are plenty of advantages tomaking your own panels other than costsavings. Originally I was going to usebalsa panels but when I experimentedwith this there were all sorts of problems.For example, the balsa soaked up a lot ofresin into the end grain so I found I hadto apply a thick coat of fast curing resinand then when that had gone off I couldthen glass over. The next problem wasthat large sheets were impossible to turnover because the balsa had no inherentstrength, so then I had to look at makinga flat table and glassing one skin thenvacuum bagging the core on, then glassingthe other side. What a drama, and also ahuge expense for the vacuum bagginggear, moulding table and consumables.With the Polycore™ I just glassed oneside in the morning then turned it overand glassed the other side in theafternoon.

I found we could use AutoCAD tonest all the components and then join

multiple sheets together reducing thewastage. I then glassed them and turnedthem over, none of which I could do withbalsa. This worked so well that I built thebridge deck floor in one piece – that was8.4m x 2.4m (i.e. seven sheets joinedtogether). The topsides for the full lengthof the boat which is 15.6m x 2.4m wasalso done in one piece (13 sheets). Ittakes six or seven people to turn theseover to glass the other side, but it wasn’ta drama. The complete sides of the boatwere finished in one panel with no joins,faired and undercoated ready to stick on.What a joy to have all the fairing andundercoating with gravity to help youinstead of doing all this on the boat!Making these large panels reduced thetime spent joining multiple panels withfibreglass tapes and creates less work forfairing because the joins always makemore work, and we had a lot less waste.

MULTIHULL WORLD POWERCATS 3

“The complete sides of the boatwere finished in one panel with nojoins, faired and undercoated ready

to stick on”

10

Of course there are other benefits forPolycore™ panels. I was concernedabout balsa panels because we’ve had afew problems with boats here inTownsville getting water in the balsa core,leading to rot. All the claims that thewater will only go to the next glue line inthe balsa i.e. at the most 100mm – aren’tquite what happen in all cases. If watergets into panels it can also move alongunder the glass, delaminating it from the

repeatedly, putting it between blocks ofwood and jumping on it, and suspendingit between stools and dropping heavysteel pipes end on from the roof of theshed. The results were very impressive.Particularly interesting was the steel pipedropped onto the suspended panel. Theglass in the impact side eventually gotdamaged but the lower surface glassremained intact until eventually wemanaged to butcher that as well. At all

2 MULTIHULL WORLD POWERCATS

core and spreading the rot to a muchlarger area. Polycore is polypropyleneplastic and so rot isn’t a problem. One ofthe tests I’ve done with sample panels isto beat the living daylights out of themwith a hammer. This is my crude impact-testing régime. The first time I did thiswas when a couple of local boat buildersdropped in and were asking aboutPolycore™‘s strength. We grabbed a25mm scrap that had been glassed withtwo layers of 600gm fabric on both sides– it was part of a main bulkhead lay-up.We placed it on the concrete and thenswung the hammer hard onto it. Not ascrap of damage. In fact the hammer justsprang back off the panel. After aboutfive or six hits on the same spot the glassstarted to get damaged but certainly notas much as any of us expected. This ledto all sorts of further ‘highly scientific’testing such as driving the car over it

times we were very impressed with thecore strength. It seems to absorb a lot ofimpact rather than just transferring it tothe inner skin and damaging that.

Delamination of the tissue or the corewasn’t a problem either.

If I ever built another boat (which mywife assures me I won’t be!) it woulddefinitely be Polycore™ again. I comefrom a family of aeroplane builders somaybe that will be a future project ...

Bruce also attributes Polycore™ to thespeed of build. “This much bigger boat hastaken 4500 hours as opposed to mySchionning which took 5000 hours.Working flat panels on the floor is so mucheasier than standing on 44 gallon drums orwobbly ladders at the side of the boat!”

Bruce believes Craig Schionning is onthe right track towards making buildingeasier. “I actually designed my boat to be

“Brucerecommends homebuilders do a lot of

forwardplanning”

11

built the way Craig’s are before his werelaunched so it felt good to know we hadcome to the same conclusion. It makeslife so much easier to build the lowerhulls and then add all the bulkheads andfloors etc leaving the sides off until there’sabsolutely no more to do inside.”

Bruce recommends home builders doa lot of forward planning. “You reallyneed to make provision early on forthings like wiring plumbing and fuel linesetc which you won’t really be up to formaybe two years. But such access is vitalin every component or you can run intotrouble later. All of Liquid Asset’s wiringdiagrams and systems in general weredesigned in advance and provision made

for how and when to fit them.” Brucealso warns owner builders to do lots ofresearch where kit boats are concerned.“Look at your complete costs includingthings like shed rental, tools, insurance etc.I’d almost recommend taking the suppliedestimated cost to build and doubling it. Ifeel really sorry for people whose budgetblows out, are in debt to their eyeballswith an unfinished boat – and often adivorce on their hands!”

Happily, Bruce and Barbara are farremoved from such strife and are actuallyabout to embark on one longhoneymoon aboard! “We’re selling thehouse and looking forward to livingaboard for quite some time. The boat is

set up for long term self sufficiency andcomfort with air con – loads of solarpanels, large holding tanks and anintegrated flywheel generator on theSteyr motors so we can belt out300amps to charge batteries! We plan tocruise locally for a while and iron out anybugs before venturing further. Tassie andNZ would be great and if we have anymoney we’d like to eventually go on athree to four year voyage through NewGuinea, Micronesia, Japan Alaska,Canadian coast, Mexico and across thePacific back home ...”

Quite an itinerary ... But somehow youjust know that with Bruce at the helm, itwill come to fruition!

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