PD Racer South Africa

Discussion in 'Boatbuilding' started by Manie B, Dec 9, 2011.

  1. Manie B
    Joined: Sep 2006
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    Location: Cape Town South Africa

    Manie B Senior Member

  2. lewisboats
    Joined: Oct 2002
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    Location: Iowa

    lewisboats Obsessed Member

    Both the daggerboard position and the mast rake are adjustable... so I can adjust how it handles as I want it. I have 4 inches of adjustment on the board and probably 6-8 deg of rake adjustment.
     
  3. Stoffeltoo
    Joined: Jan 2012
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    Location: Vanderbijlpark

    Stoffeltoo Junior Member

    Hi Manie

    Chris here from Vanderbijlpark
    I am excited at hearing from the club, I am in:!:
    I have already built my duck, sailed it and found it to be an excellent little boat. Not the fastest but definitely a sweetie to handle.
     

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    Last edited: Jan 1, 2012
  4. Manie B
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    Manie B Senior Member

    Looking very good!

    your lead seems to be ok from the photo
     

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    • lead.jpg
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  5. Stoffeltoo
    Joined: Jan 2012
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    Stoffeltoo Junior Member

    Hi Manie

    I attached a furlable jib, if not suitable for broad reaching, then at least I have extra sail area when running with the wind:D
     

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  6. Manie B
    Joined: Sep 2006
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    Manie B Senior Member

    Too me it looks ok, but could be a bit much at 17%
    I dont know these boats so it's very hard to tell
    maybe someone with experience could comment ??
     

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  7. Stoffeltoo
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    Stoffeltoo Junior Member

    Thanks Manie

    A running jib then;)
     
  8. Wynand N
    Joined: Oct 2004
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    Wynand N Retired Steelboatbuilder

    If I may chime in Manie :cool:

    The centre of effort of the sails seems to be correctly calculated.
    Provided your position of the underwater centre of lateral plane is correct the 17% lead is a bit on the high side for a dinghy type of boat...
    On a keel boat to much lead will result in lee helm that is very undesirable and one would rather have a bit of weather helm to turn the bow into the wind if the tiller is released. But these ducks may respond totally different than "normal" sail boats.

    Traditionally a dinghy has in the region of 5% lead - CE of sail(s) leading the CLR of the underwater body - but this can easily be adjusted by shortening the bowsprit or simply by just moving weight around in the vessel.

    BTW, a lead of 17% is usually associated with ketch rigs (around 20%) but varies from design to design by a few percent depending on various design factors.
     
  9. Stoffeltoo
    Joined: Jan 2012
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    Location: Vanderbijlpark

    Stoffeltoo Junior Member

    Hi Wynand N and Manie

    Thanks for the advice. Yesterday it was drawing board, drawing board and drawing board. I shortened the bow sprit by about a foot and a half, so my Jib became a bastardised gennecker (sp?). The boat behaved quite well but in light winds, the jib killed forward motion to a half kilo per hour. So thats where the furler came in:D

    I chased down a dabchick today and caught up on a down wind haul and I felt really lekker about it.

    I also took a passenger on board this afternoon and I am pleased to report that the GPS showed 8.5km/h with the extra 85kg on a broad reach. We had some hairy moments on the duck as space is limited and weight shifting not always possiple. Tacks through the wind worked great provided sail speed is faster than 3 km/h, gybes had to be forced with some tricky weight shifting with two
     
  10. sharpii2
    Joined: May 2004
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    sharpii2 Senior Member

    You probably still have some lee helm with the jib up. Either that or your not sheeting it right.

    I have often entertained the idea of a jib as a down wind sail. That way luff tension not so big a deal and the jib being set so far forward leads the boat by the nose down wind, putting less strain on the rudder and the helmsman when sailing that course.

    This idea was for a fin keel boat intended to sail long distances down wind.

    when sailing up wind or on a reach, the jib would be struck.

    Below is a sketch of the proposed around-in-ten boat to illustrate the concept.
     

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  11. DriesLaas
    Joined: Aug 2009
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    DriesLaas Weekend Warrior

    Today is d-day for routing the first set of hull panels for the cnc pd racer. Will either have a smile on may face this afternoon, or a whole lot of scrap plywood.
     
  12. DriesLaas
    Joined: Aug 2009
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    Location: South Africa

    DriesLaas Weekend Warrior

    Big smile......................
    Kit is done and it all goes together.
     
  13. Manie B
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    Manie B Senior Member

  14. DriesLaas
    Joined: Aug 2009
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    Location: South Africa

    DriesLaas Weekend Warrior

    Just a quick pic of the complete PD racer hull kit.

    It goes together with a little fitting ( you have to file out the fillets left by the round cutter. I can remove it with the router, but then you are left with a slightly larger cutout than absolutely necessary.)
    It looks very promising at this stage, I will try to start assembling over the weekend.

    The plywood we got is quite dense and stiff. It is about 750 kg/m^3, and the hull kit weighs a hefty 40 kg (88 pounds) of plywood mass.

    What is this weight normally? If it is grossly overweight I must try to save some mass elsewhere.
     

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  15. hoytedow
    Joined: Sep 2009
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    Location: North of Cuba

    hoytedow Wood Butcher

    Uitstekende! Excellent!
     
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