Bad luck about the no trip Lachlan... when I saw you might be coming, I thought "All right!" but them's the breaks. For sure, let me know when it's back on and I'll bring the camera etc. out.

Ron

Sandflyer said...

Howdy blokes,
Have in mind to counstruct a land yacht. Just some starting advise.
If the rear wheels are angled, what generally are the degrees?

As a rough giude. for fun vertical, for better grip in a good wind 4 degrees, for extreme racing gripand linear stability, up to 10 degrees.

How important is the position of the mast step?

Absolutely critical to get it in the right place in relation to the sail shape and the body weight of the pilot.

Howdy Lachie,
I understand mast step placement is important. Dimensions I was given in a post regarding a particular class LY seem to suggest a tolerance in placement of more than 500 mm along the spine, which on a craft of 2500mm in length is huge, 20% of its total length. The CoE (sail), CLR and CoG of craft and pilot are important to create best performance. I wonder if the tolerance for the class LY is to allow for individualisation of the craft to suit pilot height and body mass distribution. If you placed the mast on a water yacht at that variance with relation to length it would sail like a pig or not at all, and either have almost uncontrollable lee or weather helm.

I, like you have kicked around the net and elsewhere to get guidance on ratios and dimensions, there seems to be a rough rule of base to track ratio, within parimeters. Amongst my former Brazilian rainforest, I came across design drawings I had forgotten I had. They are of an ECHO V, new generation class V landyacht, designed by M Hampton C1986/87. I know these are old hat now, but have some interesting ideas. These little craft must have been OK, they were piloted by our blokes, to 10 and 11 in the European titles in '86, the drawings I have claim to be an upgrade/improved version.

Mast rake on a water yacht will, generally speaking, determine upwind and downwind performance, yes, hull, sail and rig design also have a hand in these things. Generally speaking a mast raked aft will allow the yacht to sail higher upwind, point higher into the wind. but downwind will not allow fastest sailing, downwind the mast needs to be more vertical or on some classes even a little forward. Some yachts have adjustable rigging, cams, over centre latches etc., which permit this on the run. One of the classes I sail, a couple of the vessels in the fleet have this rig option.

I appreciate your thoughts and insight towards design and construction. My LY project is 30+ years in the making, I purchased steel frame material when I was a teenager, it sat in the yard and rusted away to nothing. Like many of us, other things get in the way. It is now I have a bee in my bonnet and am in a position and keen to do something about a LY.

In the mid seventies we as Scouts built some very rustice LY, which we sailed as a regatta between the two Gawler troops on Port Gawler beach. These craft were mostly/all square rigged with canvas tarps, ground sheets etc., no go upwind. The craft I was involved with was paced by a motor vehicle north to south on the beach, and on many runs was paced at more than 40 mph, (60+ kmh). I or father have slide photos of these craft and that day, I will try and dig them out and then post, so all can have a laugh.
Keep up the good work, study and construction. What is your honours study project?

Hello everyone. back again, finally! Well was up to no good Easter weekend during some great conditions Had both the yachts out but spent most of the time in the larger one as my miniyacht was a little touchy. I had to point as high as possible to stop from being blown over ever second gust. After a few runs to the fence and then pushing it back i gave up and will wait for lighter conditions.

It seems it will carry out its purpose and that is to provide entertainment when the conditions are too light for the larger yachts. Im really looking forward to taking it out again ASAP.

Well the locations are fairly close, within half hour so long as agricultural activities dont get in the way. We had a ripper paddock years ago, about 1km square without a tree in it, last year it was turned over

Always on the search for smooth paddocks when travelling. The paddock you see in the pictures here was a bit rough, sailing around was rather shakey as there were still furrow lines.

EDIT: By the way, cow pads make for fun while sailing. sailing dodgem car style if you catch my drift Didn't hit any wet ones thankfully although i don't think I fully gained the experience by missing them.