Welcome anonymous guest

Please Support
TheBeachcats.com

Reefing by a smaller sail  Bottom

Go to page 1 - 2 [+1]:

  • Many times I do not go out if the winds are high . I would be able to fit a Prindle 18 sail on my 19 ,but would this make enough of a difference with 2 feet shorter in luff and about 4 inch in foot ? I also have an old 19 sail that I can remove the bottom panel of 3 feet ..

    Anyone have any experience on this ?
    txs
  • Yes, I have a smaller mainsail I use in wind forecast to be over 20 mph.

    But...

    I also had my local sailmaker put reefing points on my primary mainsail and have used them several times in unexpectedly strong wind conditions. It is not very expensive to add reefing points and I have found it to be a nice "insurance policy". The more variable the conditions are where you sail the more I would consider adding reefing points.

    Hope this helps,

    Brad in Jacksonville, FL
    Stiletto 27 x2 (one for sale soon)
  • great info .. on your primary mainsail , do you attach the downhaul and rear of boom to the reefing point holes ?
  • emmettvgreat info .. on your primary mainsail , do you attach the downhaul and rear of boom to the reefing point holes ?

    you have grommets added and material (patches) added to reinforce the sail area

    You can put smaller sails on a boat - good idea in heavier air but you may find some handling changes as a result as your CE has changed.


    I have a 5.5 and a 6.0 (mystere)
    i swap bigger and smaller jibs all the time depending on wind (on both cats)
    i also use f18 sails in higher wind (they are significantly smaller than my 5.5 sail)
    this makes a big difference
    I also can put my 5.5 main on my 6.0 without any reefing needed to reduce power

    I also have a reefing setup for my 6.0
    sail is set up with reefing downhaul and leach grommets
    there are "hoops" sewn into the sail so the bottom can be rolled up and secured with just a little line

    I also have a oversized spinlock in my mast track to secure the halyard once it's reefed
    I also use dyneema line with a jacket as my halyard to avoid any stretch once it's off the hook and running up and back down my mast

    ONE BIG CAVEAT (ok 2)
    1. when you take the sail off the hook and lower it - then secure the halyard on the base of the mast (or anywhere on the lower part) - you have changed your system from a 1:1 (hook : downhauil) to a 2:1 (halyard running up the mast, around a turning block : secured at the base on some cleat) - thus doubling the compression on your mast when you downhaul it. Add a couple human's on the wire, and a big gust - and you will be testing the tolerances of your hardware

    best to make sure your mast can take this. my system has a 2:1 on the top of the mast that a marine engineer said would help distribute the loads above the spreaders. this is a semi common solution used for the added loads



    2. sailing in heavy air with reduced sail area is a great way to handle the wind BUT your boat will still be a bear to hold on to while in the water/anchoring/parking, etc.. you still get all the spray in the face, water in the eyes and if you capsize you will have to deal with all this weather while righting - best to carry an anchor (ALWAYS unless racing WITH a chase boat) or you will be pushed without any steering until righted (and cat's sail away very well on their side)
  • I don't think changing the way the halyard is rigged will have an effect on mast load. The downhaul is pulling with a given force. Shouldn't matter if it is pulling against the hook or a 10:1 setup, unless you also crank down on the halyard.
  • i remember we discussed it a while ago. If you assume that friction is not significant, then the halyard tension would be the same as the downhaul tension, either one that you crank would have the same effect. So both equal forces pointing down would be the double compared to the downhaul forcé pulling against the hook. In practice there is friction, so the effect is something in between at the top of the mast.
  • QuoteI don't think changing the way the halyard is rigged will have an effect on mast load. The downhaul is pulling with a given force. Shouldn't matter if it is pulling against the hook or a 10:1 setup, unless you also crank down on the halyard.

    Bingo - by removing it from the hook you are also cranking down on the halyard (now unlocked)
    thus the x amount of force your cunningham/downhaul are pulling is x times 2 (up the halyard and back down)

    "Visualize a halyard lock at the top of the mast. With halyard locked it's 1:1 compression on mast to down force on halyard from Main.

    Now with a 1:1 halyard, the halyard sheeve is a block and this creates a 2:1 purchase, so you actually have twice the compression force on the stick as halyard tension. "

    http://forums.sailinganar…es-the-load-on-the-mast/

    furthermore, adding a second block into the mix (say at the top of the mast like my 6.0 has) makes this 2x down to 1.5x

    http://www.yachtsandyachting.com/photos/forum/Peaky/2009-03-18_123015_mast_compression.JPG
    Ignoring friction losses... Mast compression is least with a halyard lock (1000N in this example), most with a 1:1 halyard (2000N) and 1500N with a 2:1 halyard.
  • It's been a long time since my school days but I'm fairly certain that in a static load the sum of the external forces must be 0. So if the downhaul is pulling 60lbs the mast is resisting with equal force regardless of how the sail is rigged. Any mechanical advantage in the halyard should reduce the tension where the halyard is tied off.
    I agree that more advantage on the halyard could increase the load on the mast a bit if the halyard stretches but it can't exceed the force applied by the downhaul.
  • Forgot to mention a single block simply redirects the pull. Don't think it affects purchase.
  • Right, no purchase if you compare the halyard side vs the downhaul side, the force is the same at both sides of the pulley. The double force is the resistance of the mast to hold the pulley, standing those two forces. Take the pulley as the system and those 3 are the external forces.
  • Now what is arguable is whether you really need to apply the same downhaul force in both cases. On strong wind it's about bending the mast, not about stretching the sail or removing the wrinkles, which already happened under the forces applied. If the halyard is coming down through the mast track, then I think it's also helping to bend the mast in the same way as the downhaul, so probably you would need half the force on the downhaul (+ half the force on the halyard) for the same effect on the mast, compared to hooking the main at the top.
  • From an earlier discussion
    https://www.catsailor.com/bb_files/11514.gif

    QuoteI disagree with those calculations... The sail gets a tension of T on all three cases. The 2T and 1.5T apply not to the sail but perhaps to the mast head, wich is of little interest. The most relevant is that you need half the tension on the halyard (and double the lenght and time to raise) in picture 2. Also interesting is that in picture 2 the mast head pulley gets half of the load compared to picture one. If you want to apply constant tension with the full halyard that is relevant too.


    Picture 1 compared to picture 3 is interesting if the halyard goes down through the mast track. Imagine that it's a dyneema halyard attached at the base of the mast instead of a hook at the top, and you have a 10:1 (or less perhaps) downhaul. Then you double the effect of the dowhaul: 1T on the sail and 1T on the halyard, except that now T may be amplified with the downhaul. With other kind of line all this theory is defeated with the stretching of the line, of course. Which I bet it's the original reason why there is a hook, even on old boats without a powerful downhaul. But as said, it may sound good but you don't want to apply all that tension on the mast head pulley, you will likely break something there.
    On the other hand, if the halyard goes down at the front of the mast, as hannes-neo explains, the effect of the downhaul is canceleed by the tension of the halyard in front of the mast. Unless the fork is installed near the mast head, in front of the mast, as it is meant to.

    Edit: hope you didn't read in between my edits...


    yes the forces on the sail / luff are the same, but on the mast (head) they are increased
  • QuoteNow what is arguable is whether you really need to apply the same downhaul force in both cases. On strong wind it's about bending the mast, not about stretching the sail or removing the wrinkles, which already happened under the forces applied. If the halyard is coming down through the mast track, then I think it's also helping to bend the mast in the same way as the downhaul, so probably you would need half the force on the downhaul (+ half the force on the halyard) for the same effect on the mast, compared to hooking the main at the top.

    YES!

    so 1/2 the downhaul = 100% downhaul with the sail on the hook

    what happens when crew doesn't know this and applies 100% downhaul
  • MN3
    QuoteNow what is arguable is whether you really need to apply the same downhaul force in both cases. On strong wind it's about bending the mast, not about stretching the sail or removing the wrinkles, which already happened under the forces applied. If the halyard is coming down through the mast track, then I think it's also helping to bend the mast in the same way as the downhaul, so probably you would need half the force on the downhaul (+ half the force on the halyard) for the same effect on the mast, compared to hooking the main at the top.

    YES!

    so 1/2 the downhaul = 100% downhaul with the sail on the hook

    what happens when crew doesn't know this and applies 100% downhaul


    If there are marks they would be off, but it's another sail, the crew should not be expecting the same adjustments. And in my book its the captain's responsibility anyway...
    But the risk could be mitigated by threading the downhaul with less purchase.
  • agreed - many ways to handle the double compression on the mast

    but at least we seem to agree now that there is more load on the mast by taking the ring off the hook
  • prost
  • emmettvMany times I do not go out if the winds are high . I would be able to fit a Prindle 18 sail on my 19 ,but would this make enough of a difference with 2 feet shorter in luff and about 4 inch in foot ? I also have an old 19 sail that I can remove the bottom panel of 3 feet ..

    Anyone have any experience on this ?
    txs



    Yes. I had a P-19 with a cut down Tornado main about 20 years ago. I cut 2' off the top to make a square top main. I made a short pennate on the head and just shackled the ring onto it. The head of the sail was about a foot down or so. But, it made a great sail for higher winds where I didn't want to use my race sails. Getting the ring to hook and unhook took a bit of a challenge, but it was doable. The sail ended up fitting on my 18-2 perfectly. There is no set rule.

    The short answer is it will work if that's what takes to make it easy and get you on the water more. Some modification may look funny, but if it works... go with it.

    --
    Scott

    Prindle 18-2 Mod "FrankenKitty"
    Tornado Classic "Fast Furniture"
    Prindle 19 "Mr. Wiggly" - gone
    Nacra 5.8 "De ja vu"
    Nacra 5.0
    Nacra 5.8
    Tornadoes (Reg White)
    --
  • Quotepennate

    what is that?
    according to the dictionary it's a muscle?
    i will assume you meant pigtail or something similar?

    also how did you get the ring off the hook?
    from what i have heard, extending the head ring via a pigtail will fight you all the way trying to get it off the hook since when you rotate the mast the ring will also rotate - and almost always require putting the boat on her side to get it off the hook
  • MN3
    Quotepennate

    what is that?

    I was about to ask the same thing and expose my lack of knowledge.

    --
    Bryan in Poplar Grove, IL
    Supercat 17 owner
    --
  • I have a Nacra 5.2 with reefing points on my mainsail and with covid I sailed much more solo than ever but on the windier days I still wanted to go out.I even did it on some race days at my club so I reefed the main and sailed in 10 to 15 knot winds and found it very manageable still a challenge to sail in those winds but I went out had a blast but under control I would highly recommend reefing points on your sails for those days you just have to get out there but your pushing the limits icon_wink

Go to page 1 - 2 [+1]:

This list is based on users active over the last 60 minutes.