Kid Paravane

So dad was thinking about paravanes and outdoor activities for kids and came up with "Kid Paravane".  The idea is to have the kids use their body like a paravane or water kite.   We attach a rope to their life jacket and then pull.  Their goal is to angle their body so that they are pulling away from the beach enough that as I pull forward and toward the beach they stay out in the water.  My 6, 9, and 11 year olds were all able to do this.  My 4 year old declined dad's experiment.  Video below.  Note that Dad was pulling the rope and holding the camera while going backward down the beach and Youtube can only do so much to remove shake.

Long Line Troubles

We went out again yesterday.   We had about 80 feet of 125 lb fishing line and 20 feet of line that is attached to the top of the mast, for about 100 feet from the paravane to the mast.  

We tested the line in the office and with 8 feet of line we could stretch it about 1 foot before it snapped, so we should have about 10 feet with the 80 foot piece.   The good news is that we did not snap the line!   The bad news is that we got slack on the line and the paravane turned around in the waves before we got the slack out.  By then the two strings on the paravane had gone under and it would not straighten out.  

I am thinking I will push ahead with the all aluminum catamaran paravane design as it does not have the 2 strings that could get messed up.

I am also thinking of having the line to the paravane on a fishing pole reel.  So I would just attach that to the line on the mast and then toss in the paravane.  The reel would be set to let out the line when there was enough pull.  I think this will be a much simpler procedure than what we have been doing.   It would also make it easier to reel in the line when done.

It is a bit windy this next week so we probably won't be going out again soon.

We had camera trouble so I do not have any pictures or video to show from yesterday.

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.

Pair of Paravanes

I have a matched pair of paravanes ready for testing.   The boat is in the water.  Sea trials will start as soon as a few stars align just right.  Maybe today, but if not then probably tomorrow or Friday.

Big Pipe Paravane

This paravane uses a 1 foot long piece of 1 foot diameter pipe, a piece of aluminum bent into the shape of a water ski, and a piece of foam attached with quick ties.   The ski is to follow the surface.  The pipe makes an entraped volume of water that gives good inertia against sudden pulls.  The round shape means that it can tip and not reduce how well it works.  When going fast the foam does not add resistance as it is out of the water.  It was cheap and easy to make and works really well.

It would have trouble with catching seaweed.  With holes on both sides  this could work well as a spare paravane for either the left or right side of the boat.  Once when I was running and it hit a big wave it got out of the water enough to reduce tension but then went back in right away.

Some short pulls got my scale to read about 50 lbs.  So this is in the right size range to try attaching to my sailboat mast.   Getting eager to get the boat in the water and test paravanes attached to the mast.

Pipe Paravane

Last night I thought up a really simple paravane and then built it this morning and tested it before school!   It is just a pipe and some styrofoam.  It works reasonably well.  The two problems I see so far are that it will catch seaweed and that when the front comes out of the water it gets lighter and does not pull enough.  I will probably try a bigger diameter and shorter pipe next.   If I angle the front and have a notch all the way down the length of the pipe there will be less seaweed trouble.  Seaweed could still catch on the string.  The pipe would always be under water, so I am not sure yet how to keep the string safe from seaweed.

I could jerk on the line hard and as long as there was water in the pipe it resisted well.  The foam would lean away and the pipe would stay underwater.  This really was better than I expected.

The pipe is 3 feet long. The foam 2 inches thick and 2 feet long.

  

Tabs to keep paravane down

I have attached two small pieces of aluminum to the bottom of the two keels and angled them so that they pull down.  This keeps the paravane from lifting out of the water, which has been a problem.  I also trimmed the back of the keels so they are like the front.   I can now yank on the line and it does not jump out of the water like it used to.