Subject: Re: [harryproa] un-intentional rounding up
From: Rob Denney
Date: 2/11/2012, 5:38 AM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

 

Taking pictures of the mast, but they don't show much.  I will put them in Photos when there is a bit more to see. The two halves of the box are built and joined,  looks better than it should given the build circumstances.  Going to be a bit overweight, but not a problem for it's intended use.   Trickiest bit is getting everything on the inside so that the outside is fair and parallel for the telescoping.  


The builder has been busy on other jobs, but the german proa is getting some attention now.  Ww hull is painted, lw hull ready to close the decks.  All looks pretty good.  I am making a video of the construction, will release it when the hulls are complete.

rob



On Thu, Feb 9, 2012 at 11:12 PM, Gardner Pomper <gardner@networknow.org> wrote:
 

Rob,

I guess it is good to know that the builder is so busy... Are they working on that proa for germany that you had mentioned? Did that ever get launched?

- Gardner



On Thu, Feb 9, 2012 at 6:02 AM, Rob Denney <harryproa@gmail.com> wrote:
 

The biggest waves I have sailed into would have been 2-3m caused by 20 knots of breeze against 2 knots of current.  Hard on the wind, both hulls met the seas at pretty much the same time.  A much more pleasant motion than the corkscrewing on a cat.  


The rudders are deep enough and far enough back that it would need to be a very big wave before the bow one stopped working.  

The impact of a wave on the side of the ww hull could cause some yawing, but they are 11:1 so sleek enough that they go through the waves pretty much the same as the lee hull.  Possibly easier as they are being lifted, not depressed.  

You are right about the videos. It is high on my list of things to film when Sol hits the water.

Finally got sick of waiting for the infusion table to be available for a telescoping mast for Elementarry and started building one myself.  In the garage, so no vac, but tow is very easy (though time consuming) to laminate.  Half the spar laid up today, other half towmorrow, all going well.

rob

On Wed, Feb 8, 2012 at 11:04 PM, heinrich_meurer <meurer@airborneminescan.com> wrote:
 

there is a discussion on proa file international about the unintentional rounding up of supposedly Harryproas while sailing. I am not a member of that list but the explanation offered there is stalling of the rear rudder at slow speeds. That certainly makes sense particulary if you try to sail too close hauled. But I see another reason which I deduct from my very limited experince sailing my small mono over steep 2-3 m waves. Once you have just passed the wave crest at some speed it is very easy to turn the boat as what is left in the water at that time is part of the keel and my very deep rudder - whereas the front third of the hull is in the air. Usually I turn the boat down hard to avoid slamming. What would happen with a Harryproa sailng at 45 degrees to the waves? The first third of the super sleek lw hull would also be up in the air and the front rudder either raised or up in the air too. But at the same time the bow of the rather fat ww hull with its superstructure could get hit hard by the very same crest. This would transer a strong impulse into that hull inducing a possibly difficult to control luffing tendency.

Unfortunately I have nor read any reports of a proa - no matter what kind- sailing in such conditions and certainly not seen videos. All videos I am aware of seem to be showing "flat" water sailing under the protection of a close by shore.

Heinrich




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