boatspeed

Discussion in 'Sailboats' started by sawmaster, Dec 22, 2017.

  1. CT249
    Joined: May 2003
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    CT249 Senior Member

    It may be a reference to a day eons ago when a Tasar was taken out when racing was cancelled for the day. A video (or film) was taken and by taking bearings from the cameraman's position against the background, the number of frames per second and counting frames, Frank worked out the speed. I don't recall, though, how he estimated the distance between the Tasar and the cameraman which must surely have had a significant impact. The distance from memory was only a couple of hundred metres.
     
  2. CT249
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    CT249 Senior Member

    The Tasar is right at the top of two-sail hiking dinghies in speed terms. As noted earlier, the best way to check overall comparative speed is via yardsticks. The US one is rarely updated but the Australian one is updated annually. The biggest and normally most reliable is the UK system.

    There's only a couple of dinghies of similar size without a trapeze, rack, sliding seat or wings that will go faster than the Tasar in strong winds. The Tasar is well under 16ft; it's 14ft10in overall. Here's a few comparisons, with "assisted" boats in italics.

    International 14 - 765
    505 - 906
    29er- 914 from memory??


    RS400 (spinnaker) - 942
    Merlin Rocket (spinnaker) - 981
    Icon - 976
    Tasar - 1015
    NS14 = 1015 (from comparison to Tasar 's Australian data)
    D-Zero (singlehander) - 1029
    Vanguard 15 - 1041 (from comparison to Tasar's US data)
    JY 15 - 1057 (from comparison to Tasar's US rating)
    National 12 - 1064
    Snipe - 1095
    Laser (singlehander) - 1097
    Enterprise - 1113

    The NS14 is the boat the Tasar was developed from. The Icon is a larger boat, inspired by the NS14. The former manufacturer insists that it's slower than the yardstick reckons it is but it's logical that it's faster than the Tasar which has a rather old-fashioned hull shape in some ways.

    The RS400 gains a lot by having a big assymetric spinnaker, but its hull shape limits its top speed. Jim and Richard would know more about the Merlin. Both are very flared so they are narrow at the waterline but provide lots of leverage for the crew, and both have big rigs. In terms of pure top speed I wouldn't be at all surprised if the Tasar was faster because at such pace and angles the Tasar's flat, light hull and low drag rig could count for more than the greater power of the 400 and Merlin.

    Of course, there are smaller boats with traps that would blast a Tasar away, such as 12 Foot Skiffs and Cherubs.

    With respect, if anyone "ever sponsored a contest for highest percentage of true wind speed attained" the top Tasar crews would easily beat any other Tasar sailor who hasn't spent a decade or more honing their tuning and sailing skills in the class against hot competition each week. the jib makes a big difference in speed in such conditions and if can't use it you will be well off the pace. The 166 series were built in Kevlar and are still extremely competitive if well cared for. The previous world champs, by the way, are probably in their 60s.
     
  3. sawmaster
    Joined: May 2010
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    sawmaster Senior Member

    Thanks, CT249
    you have responded more directly to my original post than anyone else. I appreciate it.

    Saw
     
  4. Richard Woods
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    Richard Woods Woods Designs

    Actually CT249, I have never sailed a Merlin but have sailed a RS400 a number of times. It is a lot faster than a Merlin or Tasar even in strong winds (over 20 knots) when a Tasar does best

    RW
     
  5. CT249
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    CT249 Senior Member

    Interesting. I thought the Tasar may have a better peak speed because of the 400's more curved sections. Phil Morrison told me about his approach of designing a boat that went fast in light winds to be fun, and to handle well in strong winds to be easy, albeit at the expense of a bit of top end pace. It sounds like a good mixture.
     
  6. CT249
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    CT249 Senior Member

    Cheers!
     
  7. Lurch723
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    Lurch723 Junior Member

    Speed is a strange concept with a dinghy. I’ve raced Laser 2s back in the early mid 80s competitively and they were very quick when it got windy (often we were the only ones out racing when it was windy) I’ve owned an RS400 and they are pretty quick and give a very fast sensation downwind in a breeze but felt big. The B14 I used to own went fast effortlessly but the surprise for me was my RS600, my mates son sailed it against us in our Hurricane 5.9 one afternoon and it was planing as quick as we were going on a reach in waves - figure that one? Having said that it is my favourite boat of all time as it rewards skill like no other boat I’ve sailed.

    But the Laser4000 I owned was one of the nicest boats if not most difficult to sail double handlers, the RS800 was definitely very very quick upwind and reaching but never felt anywhere near as nice or fast as the heavier more flighty 4000 off wind. I used to be in the top 10 in the uk 505s back in the early 90s as a crew and we would regularly beat Dart 18s round our courses over the water when at our local club in Plymouth. So for me it’s not figures but relative and perceived pace. Peak speeds are a little false, it’s the entire performance envelope that ultimately impresses.
     
  8. sawmaster
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    sawmaster Senior Member

    I have to agree. I own both a Tasar and a Force Five dinghy. While the Tasar is much faster, the Force Five is just as much fun.Very responsive and rewarding to the right sailor inputs!
     
  9. rwatson
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    rwatson Senior Member

    Of course GPS is accurate over water surface, and ground surface (SOG) . That's ALL its good for. What you mean is that 8 knots on the GPS could be 1 knot of tide or current, 7 knots from wind.
     
  10. gonzo
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    gonzo Senior Member

    How do you calculate current speed from the reading on a GPS unless you have a second instrument reading speed over water surface?
     
  11. sawmaster
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    sawmaster Senior Member

    don't really care what percentage of speed is due to current and what is due to wind--all I'm after is a rough comparison. If I have a reading of say 7.6 knots and I make an adjustment of heading or trim and the reading jumps to 8.1 knots then I can tell that I have made the correct adjustment to increase my speed. If the original reading was off a couple of tenths then the second reading was probably off a couple of tenths as well. But the small inaccuracies due to what little current could be present in a large freshwater lake is not enough to convince me that the GPS cannot be used in this way. I'm more interested in the increase or decrease in speed rather than in the exact speed in knots carried out to the fifth decimal place.
     
  12. BlueBell
    Joined: May 2017
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    BlueBell Ahhhhh...

    You might have better luck on a Taser forum SawMill.
    Good luck and have fun!
     
  13. Peaky
    Joined: Feb 2018
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    Peaky Junior Member

    In terms of hiking dinghies, I have owned a 200, NS14, Icon, Blaze and regularly crewed a 400, amongst many others, but never sailed on or against a Tasar. The highest top speed I think was the Blaze, aided by the wings and flat bottom. I clocked 14kts according to my velocitek. The NS probably had a higher top speed than the Icon, though in most conditions the bigger Icon was quicker.
     
  14. Peaky
    Joined: Feb 2018
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    Peaky Junior Member

    I put this graph together a while back. It is crude, but a reasonable indication, I think. It assumes that performance upwind and down is dominated by a few key ratios. Black lines are the values Bethwaite considered necessary to achieve decent performance, as given in HPS(2?).
     

    Attached Files:


  15. sawmaster
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    sawmaster Senior Member

    cant get much out of the graph since three of the blues look to be exactly the same color on my computer as does three of the purples and three of the reds---so cant read the legends
     
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