Prototype Lee Board

A few years ago my late Father picked up the remnants of a old wooden dinghy (I think it was a Solo). The dagger board is just the right size for a lee board or centre board, but the end grain had suffered terrible decay.

I scraped the internal core away that had rotted badly but luckily the outer hard wood veneer was in reasonable condition. Further rubbing with a wire brush got me down to sound wood, I splashed on epoxy and waited 10 minutes for it to soak in. Then thickened the remaining and spread it roughly in the end grain. Today it was sanded flat and another layer of thickened epoxy will bring back the original curve:

I think the picture below is worth a thousand words and saves a lot of typing :). I'll experiment with the board clamped in different places whilst sailing. Chris Waite thinks an offset board will be fine on both tacks - if it is I might as well build an offset centreboard case inside Illusion which will leave the centre free for sleeping.

Heresy I hear you say? Matt pioneered chine runners for their simplicity and reliability; he says he has a mental block about anything that can break or go wrong and experienced sailors will always agree with the keep it simple and reliable rule. Coming 3rd in around Florida races you have to take your hat off to Matt for making the chine runners successful.
But traditional centreboards have been proven to work well on racing dinghies who absolutely must sail as close to the wind as possible. As Illusion will be used on lakes, rivers, estuaries as well as lumpy water the extra lateral resistance will always be useful.

Illusion's Rudder Blade

Having developed 3D software for over 15 years at one of the World's leading CAD/CAM companies I decided to go the high-tech design route:

The curved ply is the offcut from Illusion's deck beam to give a pleasant curved edge to the blade.
The large gold plate is from my Grandmother's rather nice tea set.

The large gold plate was a tad too large, but 7.5 in and 11in plates fitted a scrap offcut nicely.

 Here is the result with a 1m (39in) ruler for reference. The rudder stock has been made smaller; at first I followed the Paradox style and then noticed the Elusion and Enigma rudder stocks are slimmer with a different pivot location.

The pivot position was chosen carefully so that the blade can retract fully when she is on a road trailer. Remember I want to make the rudder captive for quick setup.

Illusion's Rudder Stock

Here is the basic principle. The rudder is permanently attached with a pintle at the top, but a stainless rod at the bottom to fit in a gudgeon on the transom.That leaves the offset rudder free to swing through 180 degrees.

This picture shows 9mm ply cut roughly to shape with 6mm stainless threaded rod clamped in place as a mock up. I'll use a 9mm - 9mm - 9mm ply sandwich to lock a 8mm rod in place, because most larger gudgeons accept 8mm pins. At 27mm thick it will be very strong, but it may need packing to fit the upper pintle.

Notice the forward skeg (it should be longer but I used an offcut). That skeg supports the weight of the boat when she dries out and stops her tipping back.

The skeg also supports her during portage. Matt fits wheels slightly forward of the COG in the Ultimate Florida Challenge to move his boats several miles overland - when he stops for a rest the boat stays level on the road.

How was Illusion designed?

With the free Carene 2008 software:

 The software is easy to use, here is a picture of early designs on a 9ft length. I decided that was too small for comfort, eventually designing her at 10ft.

You enter the length, half beam, rocker, panel heights and press the button. It's that simple.

The only real dimensions I had were that Elusion was 9ft long and 38in wide - all other dimensions were reverse engineered from photos found on the Internet.

What is an Illusion?

No not a mirage, but a 10ft boat which is a clone of Elusion the 9ft boat that Matt Layden built for the Ultimate Florida Challenge - a circumnavigation of Florida

http://www.watertribe.com/

Matt is the talented designer behind Paradox and the chine runner concept. He has designed and built a mini-Paradox only 9ft long and sailed it around the coast of Florida. Also with wheels she was pushed many miles across land (portage) in the Ultimate Florida Challenge.


I was so impressed by Little Jim, a Paradox built by Al. When I sat in her I immediately liked the aircraft cockpit concept and seaworthiness, but decided a Paradox was too big and heavy for me. When Elusion appeared at just over half the size of a Paradox I decided to build a clone.

Illusion is Launched

Illusion was launched with due ceremony into the River Hamble today. Graham Neil did his 'I'm Scottish and I cannae watch good whisky dribble into the water' act.

She rowed better than I expected, but without a rudder she can spin easily when my rowing is unbalanced. This is to be expected for a flat bottomed boat without a rudder.

It was a glorious day, good weather, great company and a very enjoyable lunch at the Jolly Sailor pub.

As you can see there is plenty of work remaining. I wanted to prove she could be rowed and test out the hull as soon as possible.