Jump to content

JulianB

Members
  • Content Count

    633
  • Joined

  • Last visited

Community Reputation

553 F'n Saint

6 Followers

About JulianB

  • Rank
    Anarchist

Profile Information

  • Location
    Sydney mostly
  • Interests
    Sailing, fine food, designing

Recent Profile Visitors

6,395 profile views
  1. When I competition "soared" your ground crew continually where moving up and down your LE, with polishing cloths, while waiting for a tow (launch). If you went though a swam of bugs on take-off, that was the end of that fight, it destroyed the performance just like that. Do the circuit, land and try again.
  2. 49ers have had "moblie phones with video function" on them for the last 5-10 years. At the Arhust Wolrd's in the Gold Fleet, they strap them each side of the boom and the director can grab footage off any of the trasmitions at will and it was live. Possibly upwards of 60-70% of the fleet had them. Pretty old tech now, but it works, its very light and beats the hell out of the old "head-cams" which where about 5kgs with a backpack and you somtimes had a hamerhead bolted to one side to compensate the "lipstick" on the otherside, a 5/16" bolt in your ear was not much fun. And it (t
  3. The aligning the final wet & dry cuts with the Water Flow, is about maintaining laminar flow. So anything that delays the onset of rolls, which are inevitable, but the delay of rolls maintains laminar flow for longer and delay’s turbulent flow, has to be a good thing. Groves running along the line of the flow means that a roll has several variable diameters, so it’s complicated and that delays the initial roll forming, hence it works. I have no idea about the shark’s skin. In the real world it flexible how that translates to a ridged hull, sorry, above my pay grade.
  4. Some comments re up and down (LE's) and crosswise. We learnt a huge amount from the alloy foils on 29ers, WRT span-wise-drift, it's also very common in miltary aircraft, so they use fences, but again, that's aero scenerio not hydro. Using say 800 and up to 1000g up and down your LE's to minimise any iregularities is 100% kosher, and infact pretty important that you do it. But into 1200 and 1500 you need to start thinking of aligning your strokes with the waterflow, LE is quite simple, just see-saw it backwards and forwards, and then short strokes for the rest of the foil. A
  5. I promised you 6 Pac's AMS/SMS rating cert. 6 PAC A51 20210513 SMS NSW.pdf
  6. Hi, sorry, but I have more than a bit on! Stupid me, too many projects and a few complications. Let me think, but in it's most basic, Down low -> downhaul and D1's push camber fwd. Outhaul or lack of D1's moves camber aft. Up-top -> down haul will pull camber fwd. Cap-shroud tension will move it aft. jB
  7. What people fail to get is that boundary layer, so the difference between a well posiled and not even waxed hull and one that is say Anti-fouled is the amount of weight your dragging around with you. Keep it very simple. A well detailed 49er (infact every 49er) has about 4² of surface area that is in contact with the water. Through the 1st 1m² away because not enough time for the boundary layer to establish, but in the case of the remaining 3m², in the case of the well detailed 49er you would have a average of 5mm, so 1000kgs (per m³ of water) x 3m² x 5mm = 15kgs of water which is ad
  8. Just pressed the send button and then remembered. We also did a trail where one boat was finished with 80g, another with 120g. Very significant difference. Then we did it again seeing the difference between 800g (wet&dry) vs a polish, also a big difference. I also remember Bora Galurai and his moth in Detroit, water was getting very close to 3.8c (water switches molecular structure about that temp) and he had to orentate the way he "effectively" scored the LE of his foils, we are talking about a scoring 5mm wide maybe, we are talking about something very fine, 800g possib
  9. As I was there that day (double trailer, road grim, that pesky Bethwaite(s), etc etc) so my list, in order of importance 1) front 20-25% of you rudder especiall the LE 2) front 25% of the centerboard, keel, fin (what ever) 3) the rest of your fin (centerboard, keel, whatever) 4) front 25% of the hull 5) rest of the rudder 6) rest of the hull. The really big reason is the bondary layer, at the bow and front of the foils there is no boundary layer, or it's miniscue. As you get to the back of a 49er or 18teen at speed it ends up being about 20mm thick, and
  10. Have to concure, go Bigfoot, custom made, guys name is Marc Seir. Fanatical, pain in the arse but arn't we all! They are up around $AUD350, so about $USD255-260. bigfootbags.com.au jB
  11. JulianB

    Laser 2

    Not sure I agree with you. Certianly the Laser ii is a progresion of the Tasar, and to some extent the 49er also had it's roots with the Tasar. The Laser ii was very much Ian Bruce and Frank (Dad), taking what was a Medium Dribby hull, that became the Tasar and North American-ing it, and they did that exceptionally well, and as you say, it's a very fine hull and a great shape. The round chine is a tell-tale sign of that! WRT the 49er, from the Tasar, you went to the Prime's then to the B18's Mk1, 2 and finally all the way out to Mk3,c. These hulls where the antithisis of Ame
  12. If you go to https://www.raceyachts.org/images/rulebooks/AMS_SMS Year Book Edition 13_2017-18.pdf You will see the rule and how it's measured. My belief is on a given day, they book a crane, and a set of scales and hang/lift them. I have seen it done at RANSA (Rushcutters Bay, Sydney) but we inherited the rating doc, of 6 Pac, the boats 21 years old. You can find 6 Pac in the system, but I don't have the Rating doc, but I will try and get it for you and copy it. Officially the boat is owned by my mate GT, and I am very confident of the number 770kgs as measured ab
  13. I think everyone should get out from behind their computers and do what they say they do, go for a good long hard sail in what ever boat tweaks their passion, and move on. You should, but then again, you shouldn't, probably not a good idea to go back and read some of the crap you have written, I would be embarrassed!
  14. https://www.dropbox.com/sh/xbyhmg82wfjww2p/AAD0KZJMcrqMyUoz9uocUuTVa?dl=0 Is the link to the photo's of the Nats, I'm 2nd from the back, Bright blue anorak with a Rooster life jacket over the top, glasses and very short beard. My old 18teen mate GT [Graham Turner, ex Hooker, Finnair, Haminex] is steering. We are A51, with bow number 20. Skeeter (a 79er) is sail number 105. Phil "Cub" Barnett who was ex Xerox & Chesty Bond was sailing it, way to many jugs of rum and coke to remember much. Re the 89er (the 8.5m new idea), I tend not to crystalise designs until I am p
×
×
  • Create New...