I starting this thread so newcommers to the sport can hopefully have a starting point for the design specs for the 2 popular Landyacht classes in Australia.
I haven't included Blokarts as these are manufactured and not suitable for the home builder.

For pictures of the some of the yachts in these classes
www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=39412

Class 5....
www.seabreeze.com.au/Articles/Land%20Sailing/Land-Sailing-Class-5-Specs-Comparisons_1422969.aspx
Plans for the "Pacific Magic"
www.seabreeze.com.au/Articles/Land%20Sailing/Original-Pacific-Magic-Plans-by-Paul-Day_1514690.aspx



Class 6....
The reason for Class 6 is that ALSA regards class 5 to be “The Race Class”
Class 6 is an “open and development class” to encourage newcomers, women and children.
Another reason is a yacht that is simple to build, looks good and can be sailed in shopping centre car parks with lots of public exposure which in turn feeds the Class 5 with completive sailors.

The current specs and design principle are simple…

1. Max width 1.8m overall
This is to enable small yachts to be easily transported and stored.
2. Max length of 2.25m (to the outside of the wheels) excluding the seat
This is to level out some of the yachts, as many different wheels have been tried from small sack truck size to 20” BMX bike wheels.
3. Max sail Area 4.25sqm
4.25 sqm has found to be safe and sufficient for learners, women & children
4. No moving seat
This is to simplify design and for safety
5. No covering OVER the pilot.
This to provide little chance of being trapped inside a yacht.
6. Round section mast only
Of any material
7. NO sail fairings in or on the sail

The design is so open to good clever design and use of materials such as moulded fibreglass, Timber, Aluminium, Plastics and good sail / rig design etc, to make some GREAT yachts.

Here is the link to " How to build a Lake Lefroy Mini " a very good example of a class 6 yacht.
www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=33825
www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=39791

In some configurations "Blowkarts" fit into class 6

cisco said...

Great post Brian. It is worth being a sticky and locked.

YES

aga

I have been doodling with the CAD and have become very interested in building a second yacht as a Class 6 for my 2 I.C. The info Brian has presented is just fabulous and I have drawn a yacht that has "borrowed" info/design/shapes from Paul and modified somewhat to suit my own requirements. I find there's some some conflicting info in that one set of parrameters I found gives a max. yacht length of 2250mm which is measured from the front edge of the front tyre to the rear edge of the rear tyre, measuring along the longitudinal centerline. The length of the Class 6 in Brians specs gives a length of 2250mm but is this the center to center distance or the overall distance over the front and back of the tyres respectively? Both of these dimensions are obviously correct (?) but which one is more "correcter"?
I do like the "Any material for the mast" as I wish to explore the possability of a wooden mast for economy of materials. Again, this depends on the current cost of quality timber versus aluminium. What would be length/height of the mast for a 4.25M sail?
Kody

Hi Gizmo
Thank you ever so much. This gives me all the info I need. I had already drawn the proposed yacht at the max. specs. for the very reason you have shown. It will be 2250mm wheel base x 1800mm overall width. What I have drawn really looks super, I am very pleased with it.
Kody

Although not at this point a recognized class I feel the Lefroy mini is worthy of consideration based on it's measurements making it easier to transport and a more equal opponent for the Blokarts (face it where's the fun in blowing the opposition out of the water- I prefer to lose by an inch than win by a mile that way you really know you've had a race)

Gizmo said...

1.8m may be a bit wide (personal comment) a better width is that of the Lake Lefroy mini.
From sailing this size yacht its often nice to be able to easily reach the wheel to roll it along .. a bit like a wheel chair to get going in light winds or backing out of a parking spot.
I prefer to have the back axle length the same or just a bit more than my out stretched arms

P.S. My (personal thoughts) in measuring I wouldn't make any measurement right on the ABSOLUTE MAXIUM (i dont like the hassles if the measurer has had a bad day or a crook tape measure) make it 20mm less than the max.

.
Keep in mind that the original CL6 spec was to match the MANTA copies that were common at the time.. . I agree with gizbot that the LLM has a nice width .you can still get an "edgey " sail in the yacht,in winds where a cl 5 or a cl6 is a tad boring. . If I was building to that width I would stick to the LLM length as well or ,again the yacht will become a bit dull

except that my steering system becomes redundant as its too far from the pedals.and short enough to make a good rollover steering set up a pain to build. The steering I fitted to the LLM is THE best ive ever had on a yacht and it relies on your feet being within a certain distance range behind the wheel


except that it no longer fits in the back of my landcruiser


except that it is now longer than a blowie and the whole purpose was to set some equalizing dimensions