Sunday, April 21, 2013

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.

Thursday, April 18, 2013

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.


Sunday, April 14, 2013

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.