Greetings from the North coast of Scotland!
Living 2 minutes from a 3 mile beach and having sailed for 28 years (plus having a degree in yacht design) my thoughts have turned to land yachts. I'm looking to build one and having read a lot of great threads on here I had a few ideas that I wondered if anyone had tried....
Idea 1 - I seen a few threads on here about weight balance and light steering. Has anyone thought about installing spoilers either side of the main beam in front of the seat? I'm guessing they could be plywood boxes with a variable pitch plywood panel to generate down force. This would obviously increase down force as speed increases?
Idea 2 - on the Optimist dinghy the mast rake is changed using a mast cup on a threaded bar and slide on the sole of the boat. The mast is supported further up by the thwart. Would this work on a land yacht? Guess you would need some sort of space frame to support the mast where the top of the tube would have been.
Idea 3 - this is my favourite but also the most whacky.....has anyone tried fitting ski's and wheels on their yacht? I' m thinking it would be fun to have a similar set up to planes that have the ski's with the wheels poking through. I'm thinking that if you're on the beach you can go into the shallow water and plane on the ski's then drop off on to the wheels back on the sand? Do you think that would work?
Just getting my shopping list together then the build will start!
Hi Barty
welcome to the forum You sound like just the sort of guy we like to hear from on here 
Keep those ideas coming There is no such thing as a silly idea here even bad ones serve as good examples of what not to do 
Not saying yours are in that category of course
I seem to remember the ski idea being put forward once before but can't remember the outcome or even if it was tried
The times I have entered the water my main concern was getting out of there which your idea of the spoiler to help with the steering response might have saved going there in the first place!
The mast cup at the foot idea could be incorporated in a tapered mast step wide at the bottom and narrow at the top
along the lines of what chook has recently done perhaps
Thanks hiko
I'm thinking of little water ski's which would be t shape so a) you would have steering and b) the rear ones offered some longitudinal stability. Plus as dynamic lift is directly to speed then as you were already moving the lifting surfaces wouldn't have to be that big.
As for the spoilers I'm thinking something like a mini f1 car rear wing but just a basic lifting surface within a base and sides that could just be adjusted, again with the speeds that yachts go I think small surfaces could give significant down force at the front end.
I'll maybe do a few sketches so its a bit more obvious!
Hi fantastic to have you join us Tartan.
I was trying to do the mast rake on the fly on a chassis I had here, but came unstuck as it requires so much effort, due to the huge amount of both downhaul and sheeting load I use on my sails.
It worked while there wasn't too much sheeting pressure, but came unstuck under very little load.
This was with a "bottom only" retained carbon mast. It had a 285mm long adjustable mast step that was retained at the top and used bottom adjustment. I adjusted with the screw and thrust bearing mechanism taken from a car scissor jack. I was using a 3/8" drive ratchet from a socket set to adjust it. I then moved up to 1/2" drive, but the whole thing got out of hand weight wise, to have enough strength.
The screw just couldn't handle the loads applied. The first screw buckled in compression and even in tension the thread just stripped out the thickened nut I had fitted to control it.
I haven't given up just ran out of time.
A mast that has stay cables may be different though. Well worth a try.
The pictured adjustment would work well for quick alterations between sailing sessions.
Hi Chook
What sort of travel are you looking for at the base of the mast? I assume you are looking for 'on the fly' balance adjustments as opposed to upwind/downwind rig settings as it must all be apparent wind sailing anyway?
I'm thinking an angled (45 deg) mast support with a flexible mounted tube section at the top then a section of yacht traveller rail with carriage on the main beam below the tube section. I would use rope as the adjuster with a 32:1 course tuner and potentially a 64:1 fine tuner with the ropes led back to the front of the seat on spinlock cleats or similar. Yacht travellers are designed to be adjusted under big loads so should handle it. I guess the actual amount of fore and aft travel would be like 20cm or so?
Sooooo thinking about the water ski's though lol
Just read your thread Chook and saw the adjustable tube....could you not have a slightly wider section of tube with a ptfe base plug on the base of the mast with an eye welded on then with a circular hole cut in the mast tube connect a 'snap on' block to the eye with a 32:1 pulley system going back to the seat. I'm gussing that the mast base always wants to move forward. You could then just pull the mast base aft or release to let it drift back?
I like that idea !
Would be good to try on big areas like dry lakes etc I imagine
This is what it ended up as.
. 
Where the rear adjuster nut is now welded to the mast step is where the jacks acme thread passed through a 3/4" hole and back to a bracket that held the thrust bearing at the handle end of the jack.
I just welded an cheap socket to the end to take the 1/2" drive ratchet.
The mast end of the thread had a heavy washer welded onto it that was retained in a U bracket that was welded onto the bottom of the galvanized mast support. This shot show how the 1/2" thread now just pushes onto the 60mm x 2.3mm pipe.
Statically it work really well........and enough to keep me fiddling with it for way to long. Kidding myself I would never sheet in this hard.
In the end I walked into the workshop after having a cup of coffee.......... cut it all off and "Fowl Play" was born.
Is this what you mean with 32/1 
I'm busy tidying up #12, one of my old LLM test chassis from 2012.
It's had more cuts than the federal budget.
Cheers.
