Visionarry, Hurry Up - telescoping mast, Rudders...

Newsletter from Rob Denney, Sept. 2002

 
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3 Visionarrys sold in 3 weeks. The first 3 people to see the renderings of Visionarry bought plans (to see images Visionarry Gallery ). One is in Holland, one in Australia (where Mark will be keeping an eye on progress) and the third is in nth eastern USA. Construction photos will be posted as we get them. The 4th person to see them chose a 12m/40 foot version. This will be built under Rob's supervision, in Perth in the New Year and is destined for the Fort Lauderdale Boat Show.

Specifications:
LOA: 15m / 50'
Windward hull length: 10m
Beam: 8m
Sailing weight: 1.4 tonnes/3,080 lbs
Payload: 1.4 tonnes/3,080 lbs
Sail area: 80 sq m/860 sq'

 
          
click to enlarge these images


'Blind Date' specifications are correct, though difficult to believe. The materials list, ex sails, freight, wastage and taxes totals $Aus25,000/$US14,000. Materials lists on new boats are notoriously difficult to calculate and are invariably low. Based on any other 15m/50 footer these weights and costs seem ridiculous. Based on Harrigami (see Harrigami) they are much easier to believe.
(more about Visionarry design)



'Hurry Up' our Racing Harrigami is in one piece. The demountable kiri/carbon beams are installed in sockets in each hull. Not super rigid, but at 6.5m wide it wasn't expected to be. Windward hull (strip planked kiri/glass) weighs aboiut 50 kgs/120 lbs. It won't be much fun to live in, but could not be any smaller and meet the rules


The top half of the 15m telescoping mast is built and bends in static tests exactly as predicted. It is a bit heavier than predicted, but Rob attributes this to the learning curve. Lower mast halves are built and the bearings are inserted. There are a bunch of tests to do to ensure the telescoping will work, but should all be in one piece soon.

This mast was built using a new technique which Rob has developed. It results in a mast which is lower cost than an equivalent weight aluminium spar, and is much stronger and stiffer.

The technique requires very little in the way of moulds or expertise and uses vacuum pressure to ensure a void free, well compacted laminate that is not far off what we would expect from heated, pressure moulded prepreg laminates. It is, however, fairly time consuming. The 7.5m top mast on Hurry Up took the best part of twenty hours to build. This did include a fair bit of learning. It is very cheap. Hurry Up's two piece, unstayed mast weighs about 50 kgs/110 lbs. The material cost is about $1,500. This is $AUS30/kg $US7.50/ pound (bit difficult to be exact at this stage due to errors, unfinished rolls and the cost of flying in the carbon instead of shipping it). Cost would be $14,000 if it was built using conventional techniques.


'Hurry Up' showing full sail, one reef, and deep reef using the telescopic mast.

So, although the prognosis is good, there is a fair bit of testing to do before selling plans for masts. The testing is a 3 stage process. First, Bruce (harry proa engineer) has stipulated the laminate schedule to be used and some static tests to perform. Second, the mast will be tested on Hurry Up in the worst conditions we can find. Third, we are sponsoring 4 students at the University of Western Australia engineering deprtment to analyse some samples built using the technique. This is a long term project under the supervision of Associate Professor Xiazhi Hu, a very experienced and helpful composites expert.


The rig on Hurry Up is not an Easy Rig. It is an experiment to see if the gains of a taller mast in light air are worth the increased capsize moment in heavy air and the extra work and gear needed to make it work. It is not worth doing in a short handed boat where the EasyRig reigns supreme. However, the racing rules stipulate 4 crew, so the una rig was tried. If nothing else, it gives the extra crew something to do. Making it telescoping complicates the analysis of the buiding technique. Hopefully, these complications can be allowed for.


New rudder design: Rob reckons he has tried over 20 different rudders on his various proas. All were a search for the holy grail of proa rudder design. This would be a rudder that kicks up in both directions in the event of grounding or hitting something Can be raised or lowered and still be steered Has no holes below the waterline Can be raked aft or raised for helm balance Is cheap and easy to build and install The new rudders look like doing all these things. Testing should happen on Hurry Up before Xmas.

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