Hi,
Been out last 4 out of 5 days. Oher day was surfing.
50nm down coast to Bunbury, had moderate but gusty ESE which was offshore but forawrd of the beam so a bit more effort to steer. Long day as wind weakened - took 10 and a half hours.
Back the next day after abandoning thoughts of going further down towards Geographe Bay beacause the southerly was already in.
It was light at the start but the bureau of meteorology gave the windspeed 21 gusting to 25 knots by the time i was arriving back at Mandurah.
Time for return journey was 6 and 3 quarters hours.
I practiced the reefed combinations and found the main reefed alone with no jib worked well. Next option would have been bare poles.
Next day was 35nm to Rottnest. Similar onshore seabreeze, not as rough only 15-20 knot seabreeze from astern port quarter. Reefed the jib first and
carried on with the full main. The boat was fine except for running the ww hull nose first into waves. This is partly due to the 8:1 length/beam ratio and probably the overloaded design use. Basically it is too small a boat for the wavesthat built up.
Today coming back down from out at Rottnest Island, I had to luff off for a few hours to stay dry as some NE'ly winds 13-18 knots built a reasonably choppy sea. Once into the lee of land (Garden Island) it was full throttle and averaged 11kmts down to the end of Garden Island ( 5.5 miles in 30 minutes). The big monohull was about half the speed.
Pulled in to shoal water and over the Penguin Island sand bar with the rudder up and working at 45 degrees to anchore in Safety Bay (actual name).
Very refreshing achange from boat dust and resins.
Certainly inpressed with overall performance.
Doug
--- On Tue, 30/3/10, Rob Denney <harryproa@gmail.com>
wrote:
From: Rob Denney <harryproa@gmail.com>
Subject: Re: [harryproa] Re: off axis between tow
To: harryproa@yahoogroups.com.au
Date: Tuesday, 30 March, 2010, 21:48
Join half way up the sides if you can. A flange on the inside and double bias on the outside.
Fun day today, making a rudder shaft in a pressure mould, held closed with a dozen 6 and 8" (150 and 200mm) G clamps. One broke, then 7 others, then the sides of the lid broke and finally the bag burst. Not hurt, but there were bits of busted clamp all over the shed.
Be careful with pressure, and don't expect cheap clamps to be as good as expensive ones.
rob
On Tue, Mar 30, 2010 at 11:45 AM, robert <cateran1949@ yahoo.co. uk> wrote:
Definitely a box beam; 250mm square cross section, 12mmx 60mm carbon rods in the corners, 15mm core with 680 +/-carbon twill and 200g carbon 90 for the top and sides, extra for about 30mm from the corners to distribute the stress, doubling up at the lw hull area with extra tow wrapped around the outside and bulkheads inside for point compression loads. Still working on the best way to join the two halves. Joining at the top and bottom means that there is continuous material on the highest stressed area. I am even contemplating putting a central vertical web to facilitate the joining.
--- In harryproa@yahoogrou ps.com.au, "Peter Southwood" <peter.southwood@ ...> wrote:
>
> An important point, as a box beam is vastly better at handling torque.
> Cheers,
> Peter
> ----- Original Message -----
> From: Rob Denney
> To: harryproa@yahoogrou ps.com.au
> Sent: Monday, March 29, 2010 1:11 PM
> Subject: Re: [harryproa] Re: off axis between tow
>
>
>
> All good but don't underestimate the torque in the beams, it can be quite high, although as the box is big does not need a huge amount of material to resist it. Are you having one web (I beam) or 2 (box)?
>
> rob
>
>
>
> On Mon, Mar 29, 2010 at 8:57 PM, robert <cateran1949@ ...> wrote:
>
>
>
> The 680 twill is for the web of the beams instead of 2 lots of 600 glass. 200 for the inter layers.
> I see that for the rods the interlayers do quite different jobs compared with the interlayers for the rudder shafts as on the shafts they act as webs as well as providing torque resistance.
> Provided the compression at the deck edged is well sorted the rods should be under compression and tension with little bending or torque.
>
> Good point about checking the scrim type.
>
> --- In harryproa@yahoogrou ps.com.au, Rob Denney <harryproa@> wrote:
> >
> > Between 2 and 6mm depending on who you speak to and the application, so 3
> > should be fine. Because the off axis and the zeros do totally different
> > jobs, there is not much to match. The twill is overkill (200 glass will do)
> > for intralaminar shear (the reason for the 2-6 mm layers) but will
> > contribute a lot towards twist resistance. I used 19mm pultruded rod for the
> > beams on W. Had what looked like a layer of glass cloth running higgeldy
> > piggeldy through it. Didn't break.
> >
> > Glad the core arrived, was starting to worry. Vacuum test a piece before
> > you start to ensure it is the right weight and has the resinproof layer.
> >
> > rob
> >
> > On Mon, Mar 29, 2010 at 4:02 PM, robert <cateran1949@> wrote:
> >
> > >
> > >
> > > I am setting up for making my corner rods for the beams. I am working on
> > > 3mm between off axis layers. Is this about right. I am using 200g carbon as
> > > I will be using 680 carbon twill +/- 45 and tow at 90 for the web and want
> > > to match characteristics.
> > > The polycore has arrived and now to get it down to Canberra
> > >
> > >
> > >
> >
>
>
>
>
>
>
>
>
>
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