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The Mad Hatter

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Everything posted by The Mad Hatter

  1. When keeping a structure in column to resist compressive forces making it thicker is the best way. One layer of 6mm foam and a layer of carbon would add around 6.2mm which would work far better. Much better still would be if the layer of foam was on its edge and wrapped in carbon. When I started building the Mad Hatter I already had enough 8mm core cell foam for the hulls but 10mm was specified. I worked out the hulls would be twice as stiff with the 10mm. It is not a linear relationship between stiffness and thickness so I bought the 10mm foam. If you want to keep it in
  2. As a rule of thumb uni carbon has the same tensile strength as stainless steel for a given cross sectional area but 1/7 of the weight. You could use that to help scale the F85 chainplate down for your application and unlike the F85 fit it to the part bulkhead before installation. See pics below. The chainplate fits into the slot in the B/H and angle for a straight pull to the hounds and laminate in with 450gm double bias. I was sure that I took pics from the inside after fitting but cant find them. The last pics shows it fitted during the fairing and painting stage.
  3. I had a look at your edit and it is better because the compression load on the deck could be managed in the height selection of the bridle and the load will be transferred to the side of the hull where it needs to be. It is also light weight. However bolts in an area of hull had has not been planned to have bolts can be an issue because they can crush the lightweight foam. Also they often find a way of leaking. Any attempt to tighten them to minimise leaking will also crush the foam it not already and the leaking will just get worse. I have also built small Off The Beach cats and it used to
  4. I agree, but a scaled down version both in size and laminate would be the a really neat solution. The Mad Hatter was my 16nth boat build and I promised the misses it would be my last so I took thousands of pics. If I find a backup I should have something on it.
  5. I suppose the closest solution that I have built for this particular application would be the side stay fittings on my F85SR. The forestay on the F85 is different because it is part of the carbon socket that takes the carbon spinnaker pole. Building that that was a more interesting because I made a collapse able mandrel to make the carbon socket. I may have picks of that too but it is not really applicable for what you are trying to do. When I get a chance, maybe later this evening, I will see if I can find relevant picks , I think I backed them up before my old laptop died..
  6. A bit like fitting truck tyres to a Ferrari. Heavy, ugly and slow.
  7. I think you may pull a big hole in the foredeck. To be safe I would be trying to transfer the load to the sides of the hull. A carbon chainplate attached to a b/h and b/h laminated to each side , even if only half height would be what I'd be doing. Make the chainplate so a fore and aft pin takes the forestay when the forestay thimble fits into a slot cut in the chainplate.
  8. That would be giving the fun part to the loft and keeping the boring part for yourself and severely limit what you learn. But if you just want sails it would be one way to go.
  9. Unless you plan on making radial cut sails the main and jib are pretty easy to design and loft with very basic tools. A batten that will bend evenly , pencil, measuring tools , string line etc. It really is great fun learning how to shape a sail using luff curve and seam taper and then modifying the sail by playing with these variables. I'd go that route before looking for software because of what you will learn along the way. If you have the time and inclination I think it is well worth it.
  10. Is the head gasket OK? I had a similar problem with a ride on mower and it turned out to be the head gasket.
  11. I went down the same path around 30 yrs ago. Main and jib, no problem. A good shaped Spinnaker may be a bit trickier. The learning process was a lot of fun and the ability to modify the sail between weekends really helped with the learning. Get your old sails out and make sure you also measure the seam taper and luff curve so you have a starting point . The best of luck.
  12. While I hope I never have to repair my carbon mast I could if I needed to. I would not need a 30ft long autoclave in fact even if I had one I wouldn't use it to repair the mast. It would be handy to have a vacuum pump and maybe a compressor depending on the method I chose.
  13. I would probaby inject epoxy glue and clamp. Then sand the entire b/h and laminste with 450gm double bias each side.
  14. I have only ever raised and lowered my 42ft carbon mast using cabin top winches. Never tried it with a trailer winch.
  15. Just in case you have not done the numbers _ The weight diff between a layup of 450/600 glass and 320/320 carbon would be around 5kg. Ie. 13 compared to 18 kg if the hull surface area was 6 sq m.
  16. There is no way you will bend the panels with a layer of carbon each side. I would laminate the inside on a table and then fit the panels to the frame. Once taped I would remove any screws and fill the holes. The panels then should remain in place while you laminate and vac the outside laminate. If there is an issue bending to fit to the frame then heat the panels. I found 105degC to be the ideal temp for the M80 foam. It is a shame they didn't supply female frames. Then you could fit the foam before laminating and vac the inside laminate, remove and vac the outside. That
  17. I've put in a dual tiller. I have tennis ball on the end of each to act as a stopper while they slide through a bungie loop that hangs from the top back stay pulley . They are suspended around 18 inches above the deck . Not only is this a big improvement over a single tiller but having them hanging like that keeps them out of the way but still handy to grab.
  18. Apart from below;- The difference between adversity and adventure is attitude.
  19. I bet that is one of Ian's upgrades because what they have done is consistent with the way this is treated in the F85SR plans. This just gives a bit more space into the fwd berth. The ring frame is quite small near the seats however it is strengthened with a 50mm wide flange. That pic looks like this is done and they have missed painting under the flange which makes it look like a gap. Also the flange is supposed to be on the fwd side of the ring frame. Looking at pics on the Farrier Marine site the ring frame looks the same with the exception of the flange being on the f
  20. My understanding is there is no limit to sail area under the 8.5 rule. The primary limit is how high the mast can be above the water. Given that Ian designed this one for the rule he would have put as much area as he could within the confines of the rule. Have you compared the area of the F85 to other boats sailing under the 8.5 rule? Apart from increasing the size of the head on the main sail, the foot length is the only other option. But you would only play with that if you had to because it may create a helm problem and moving the D/B aft or increasing the size of the rudder
  21. This pic shows the head relative to the rest of the package.
  22. F85SR, Carbon Mast of 41.5 ft , Main has 6 foot head and 10ft foot. So head is 60%of the foot and works really well.
  23. Wouldn't doubling sail area like that have a significant impact on OMR?
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