Thursday, May 16, 2013

First Sea Trials

We have been out on the boat twice testing a paravane.  The first two days we have only tried on one side.  While it was out the boat did seem more stable. 

With the paravane tied near the top of the mast it has a lot of leverage.  It is almost 10 to 1 leverage compared to the cables from the side of the boat to the mast.   For simple arithmatic I will pretend that is it 10 to 1.   If I had 200 lbs of pull from the paravane that would be 2000 lbs of pull on a cable supporting the mast.   Because that might break something, I am trying to limit the paravane to 100 lbs or a bit over.   I am doing this by using a line to the paravane that will break before anything important in keeping the mast up does.  

The first time the spool that I was letting the string out with broke.  The paravanes pulled so hard it snapped the plastic spool.   I had two strong lines and a short 100 lbs test line in the middle and it snapped that.  Decided to risk the mast and use the two strong strings and it snapped an aluminum carabiner.  Eric and all 4 boys are with me on this day.

The second day I used 40 feet of 100 lbs test fishing line, that will stretch,  from the mast line out.   This worked better but still broke.   We only had a paravane on one side and were outside the reef.  Nils, Ethan and Teryn were with me.   When the line breaks you can hear my cameraman Teryn say "grabber grabber grabber", "here daddy take it". He got my "paravane grabber", which most people would call a "mooring pole". :-)   It worked great for getting back the paravane.  Nice to have some boys to help out!

The basic problem is that with only one paravane the mast can tip toward it enough that the line goes slack then move away getting momentum so that when the line gets tight it snaps.

I think if I had 80 feet of 125 lbs test line, with paravanes on both sides before leaving the harbor it would work.  So that is the next experiment we will try. 

We tried to go out Friday May 17th but had some trouble with the new tank of gas we brought.  Hope to go Saturday.

Having some back trouble and so not getting out as often as I would like.

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