Class3

OK Vic, I keep popping back here for progress on the new mast and finally it has got the better,of me. I have to ask. Is that a 650 A10 bottom end sitting on the bench?

Worked on one side of the mast , Used 1/8"ply for the web with one layer of woven glass. Epoxy Glued in the 12mm aluminium bar. Ready to start side two. Many thanks to Kiwi307 for the info on how to go about building this thing. And to all others that have put in impute.

Note:
(I found that contact glue reacts with the foam in the same way as polyester resin, lucky that I tested it first.)

Just be using what Kiwi recommended, Woven glass.

By Kiwi earlier in this post

WING MASTS FOR THE HOME BUILDER. Please be aware this is a method from which a large number of wing masts of various profiles, sections and sizes have been built. I am not intending to make the design decisions for the builder, just give a very successful method which has stood the test of time, and the rigors of Landyachts. By the way, this is not my sole ?intellectual property? A number of people have been involved in this evolution. Landyachts have immensely stable platforms, the loads which are applied to the rig are huge, and the apparent windloads are readily in excess of 60 miles per hour. The method seems almost too simple, and many people have said that the wings will not last, believe me they have stood capsize onto hard ground at 30 miles per hour plus, compressive loads which will part 6mm 1 x 19 stainless wire and still keep going a number of years later. The hardest part is making the decisions over section and proportion of total rig. I have generally gone for an area of about 15% of the total sail area, and section is usually a NACA symmetrical one, with a fore and aft dimension of about 12 inches, and a thickness of up to 4 inches. Another way is to consider the foil of the whole sail plan which you would like to achieve, decide on the wing chord, then plot the curve of that, then make this a symmetrical section (assuming you are making a ?two way? rig) Strangely after having done this a number of times on paper, it usually matches a symmetrical NACA section, don't know why though! My choice has always been by guess, others have spent many hours plotting L/D curves, the results on the beach are very hard to tell apart. Isn't theory wonderful? Now, how to do it. Material of choice is ?blue? polystyrene foam, commonly used in this country on the outside of houses. It is cheap and accessable. You also need a piece of clear straight timber the length of the mast, make this up earlier, scarf, or one piece, it doesn't matter, also needed is the sail track, I have used both alloy and plastic, proper sail track and caravan (trailer to the North American) awning track. All have worked. Choose one with small flanges, or cut them off Also allow to cut off the thickness of your ?trailing edge stringer? from the section drawing. Plot this onto the drawing, to see how it will fit, and transfer to your cutting patterns which I usually photocopy and glue to the hardboard pattern material. Make patterns of the foil you have chosen, we usually use hardboard, some have done it with alloy sheet, but any hardish material is fine. The patterns should be as smooth and accurate as possible, this avoids the hotwire ?snagging? on roughness. The patterns need marking evenly with a numbering system, at intervals of 5 to 10% of the distance around their perimeter, I usually start at the leading edge. Also mark a centre line, and drill a couple of holes through which some 3? nails pass firmly. As the blocks of foam which we can get are 4 feet long you need to design the wing in multiples of that dimension (easiest anyway). Most of my wings have been parallel section except for the top one or one and a half sections which taper. Now nail a pattern on one end of the foam block. Using ?wind sticks? nail a pattern on the other end of the same block, check for as little twist between the patterns as you can achieve. (The human eye and long wind sticks is the best way we have yet found). Using a hot wire and foam cutting bow and TWO PEOPLE start cutting into the leading edge, make sure you are both going to go the same way, ie up or down, yes we have gone opposite ways and it makes very strange shapes. When you are JUST touching the pattern begin calling the previously marked numbers so that you keep as close to each other as you can, Call out, 0, 5, 10 etc but try to keep moving. The one who is ahead should slow down, rather than rush the slower cut.-when you reach the trailing edge cut away. Now repeat going the other way round the same piece. KEEP the offcuts, they make very useful bits to rest it all in. When you have cut all your pieces, take a break, the most nerve wracking bit is done. Now glue all your bits together,(glue can be anything which will glue foam it needs no strength as the foam would only break away from the glue anyway) BE ACCURATE, do not keep the patterns attached. If you think about it you may have had to only make a total of 3 patterns, as you just move onto the next block, if the tip is only one piece long. You should now have a great big long piece of foam which you are now going to glue to the trailing edge stringer. Again check for twist and bend. By now you will have realized that you need a bench at least the length of the mast, although I have made them on the floor (of the hallway in the house). Again just use a basic glue, hot glue, Gorilla glue, 5 Minute epoxy etc. This should have taken a reasonable evening so far, so either stand back and admire, or carry on! The next step is to cut the whole thing in half! Through the major thickness. Has been done with saws but the hot wire is easier except where you hit the glue lines. This is a cut from side to side, running from top to bottom . Now is another choice. I have made this next step, the ?web? from 3mm ply, or tri-axial fiberglass. I have no preference. If using glass, round off the edges of the trailing piece of foam to allow an easy lay of the glass. (Usual radius rules apply). Now lay the glass tape, make a good weight lay up, 16oz plus and epoxy to the foam. Easiest way is with the mast on the trailing edge stringer, CHECK STRAIGHT AND TWIST AGAIN. Wet out the foam, apply the tape, squeegee etc, make sure the tape wraps round your curved edge nicely etc .Use good quality epoxy If you choose to use ply, glue the ply into one long web (usual scarf joints) then glue onto the foam in a similar method to above .Use good quality epoxy NOW let it all go off hard, ie LEAVE IT ALONE! If you used a ply web, use this as a guide for the router, cut a groove into the trailing edge foam, against the ply, into which you are now going to glue a 12mm (1/2 inch) alloy solid bar on each side of the mast. Let this go hard. Use good epoxy, and follow instructions re gluing alloy. Glue the leading edge back on Cut away the foam as far back as the web for an area about 6 inches either side of the hounds fitting. Make up a wooden block (cedar etc) to take up this space. While you are playing with wood, make a base from wood, I think this should be about 3 inches thick, either end grain or a more solid timber and the complete profile of the mast, and a tip which can be about 1 inch thick.. How you deal with halyard etc is your call, halyard locks are my preference. You now need to attach the track to the trailing edge, glue works fine. Fair the whole trailing edge, leaving some means of keying it all together. At the same time fair in the hounds, base, and tip. Epoxy filler is fine. If you wish now carry on to the next step, you do not need for this filler to cure. The next bit is the most time consuming. This is the covering which is load bearing. Depending on the length of the mast, sail area etc the glass layup will vary. For a 20 foot long I have used as little as 2 layers of 6 oz woven cloth with another 2layers around the hounds fitting. Usual thoughts of spreading the size of patches apply. I have also used a bit more sophisticated lay ups, S glass etc, and also run a tove of carbon down the web from top to bottom. All have survived so I am undecided on what is needed, probably less than we think, but probably a bit more material is not going to weigh much, the cost is minimal, and the unit will live longer. I have always done this with the whole thing standing on the trailing edge, the glass going past the track for later trimming. Brace the wing, so that it does not fall over, is straight and not twisted (yet again) This time you really do need to stand back, breath a sigh of relief, have a coffee, etc. Let the whole deal cure, then fill and fair till you are happy. Fasten a hounds fitting (which will need to be custom made) experience tells us these are single point attachment standing off the leading edge. Fit a mast support on the base. Again a cup fitting seems best, usually directly under the major width of the mast. Too far back, and the mast will oscillate which can get rather exciting, too far forward and it will over rotate VERY easily.- How long does all this take? Masts have been made in 2 evenings, and sailed less than 36 hours later, but this is pressing too much. Easily done in a week of evenings, if everything is to hand. Do they work? Much better than a standard mast, is it worth it? If you are building a multihull, you are already stretching the performance envelope, take the next step! What should sails be like? Most sailmakers do not have a clue on how to make sails for wings! All the successful sails for wings which I have seen (and there have been a number) are PANEL FLAT, with a touch of luff round, (less than 1%) about 33% up from the foot. If there is panel shape you will get a sail foil, trying to blend into a mast foil. What I call a ?double bump? and it is slow.(Have seen lots of these too!)

Thanks Wok ended up using aquadhere

A quick note Vic,
Take care using aquadere, as it doesn't always dry on the inner parts of the surface as air can't get to it. Foam is not porous like wood.

Thanks Bill, I found that problem when I set up the first couple of pieces . Changed to another type of glue (gorilla) let it dry for a day or two and broke it.apart and the glue was dry and good contact.

Wok I do not think that there is any strength in the foam , but with the web and the foam shape it stops the fibreglass exterior collapsing against each other. Maybe I could be wrong but I think that is the idea behind it

Both sides of the mast are together now, started on the sail track today. quite enjoying this project

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SJK said..

In addition, have you considered building a sail raising system at your mast?



If you place a pulley at the top of the mast and put a steel cable on it, with on the other end a rope (see picture), you can easily raise your sail without having to put the whole yacht on its side.
If you are interested, I can take some better pictures of the system.

Stephan

Well, approximately a year ago I posted some pictures of a sail raising system for in the mast (page 4 of this thread) and said that I could post some better pictures and give some more details. Clearly I forgot to do so, but since Vic asked me, here they still are.

The general working principle I already explained. In addition, for I do not now if it is clear enough to see in the pictures, the sail has a strengthened hole at the top and a shackle is used to mount the steel cable to the sail.

In the following figure I added some dimensions I measured. The mast which is shown and from which I took the dimensions is approximately a little over 5 meters with a sail of approximately 5.5 m2 (It’s used on a yacht of the international DN class).



The rope that is connected to the (stainless) steel cable is only used to raise the sail, during the sailing it is completely outside the mast and there is no load on it. A plastic sphere is bounded to the end of the rope, so it will never get into the mast. During sailing, the end of the stainless steel cable is fixed behind one of the pins that is on the bottom of the mast. The rope can just be winded around the mast to get rid of it.

The hole in the mast from which the rope comes out has a tube attached to it (made of glass fiber I think), or otherwise just some hard plastic. I am not sure whether it goes throughout the whole of the mast or if it goes only through the lower part.



If there are still some things unclear, or you need some more specific pictures, just ask and I will try to help as good as possible.

I'm afraid I can't help with that at the moment, we actually have no breaks at all on the yachts.

Started laying up the mast today, Big job fibre glassing this one

ready to start



draped glass



one layer done, will apply 2 layers around the hounds before next layer of glass

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aus230 said..
for my own reference
www.seabreeze.com.au/forums/Land-Yacht-Sailing/General/Tutorial/

Looks great. I have never bothered with a halyard (sail raising device.) 1 reason is that there is a large compressive load, part of the reason that most wet yachts in the more competitive classes use a lock at the top of the mast. In my case I always laid the mast to windward of the assembled yacht, attached the windward and fore stays then moved it till they both had tension, then slid the sail up the mast and tied off at the tip of the mast. with the mast at some angle to wind (45 degrees ish) I could then simply pick up the tip of the mast and the breeze lifted it gently into place. Then attached the boom. I used this for many yachts and years. It does mean you make the 2 components of the mast step with that in mind. NZ rules always required that un attended yachts were laid on their sides so you get pretty handy at thinking this through so you can do it on your own :)

Brake question; what we did here in NZ and Europe was apparently frowned on by your countrymen so best I don't give detail. It was possible to stop a 3 from near full speed in a few lengths, but makes a mess of the sailing surface :)

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aus230 said..
Hi Kiwi
Thanks for that.
I have a problem with the mast when I turn upwind the mast flaps severely. I think my mast attachment at the base is to far forward, Should it be more central to the mast.

Cheers
Vic

That is not fun, especially when it oscilates enough to lift the front high enough to go over a security fence as Colin Palmer once did! Where is the base on the mast now Vic? I think from vague memory that mine were under the main web, ie about 1/3 back.

Looking a little worse after her free run on the Lake




some of the damage



Started repairing the damage to my class3 after it decided to go for a sail by it self. Repaired the mast, (top section broke off) repaired the front beam(split in impact with a causeway) Repairing the back beam( cracked on impact with causeway) I repaired the front beam and and rear beam by wedging apart cracks and injecting resin. then clamping together. (suggested as a way to repair by Bill Finch. Thanks Bill) I will plane the back axle some more to get a bit more flex and wrap the ends in light cloth. I did not think the mast could be repaired but I think the repair will hold up fine, I reinforced the section that broke.

Thanks Kiwi
The mast hound is as recommended, at front 4m up, the turnbuckles are marine, they where undone to get the front wheel into the recovery vehicle. Take you point though, I have always put a safety wire through the shackles but never thought of the turn buckles. will do from now on. I will move the pivot point an inch back.

Never expected that the yacht would get away, It was parked with the front against a causeway, front wheel in a tyre and the back wheels chocked and no sail. The wind hit 50knots during the night (flattened tents) it pushed the yacht with tyre up over the causeway and away it went. it was found 15k away over another causeway. Lesson learned tip the yacht on its side.

""does this give some indication of how efficient the wing mast is?""

That afternoon "Big Mick" was sailing his mini by holding up a plastic shopping bag as a sail.

Your yacht Vic, did a lot of kilometres with both you and Graeme sailing it with just the mast.