DaySailer.org Forum

Can someone please notify me about good measurments for a spinnaker on an O'Day Daysailor?

Mike (punkrock2028-at-aol.com)

This is from the measurements page.

Head to clews: 15 feet, 3 inches
Head to mid-foot: 16 feet, 0 inches
Mid-foot to clews: 6 feet, 0 inches

Additionally the max size of the spinnaker pole is 74 inches. Hope this helps.

Although the boat I sail has a spinnaker, it has not been set up for use yet. The owner had purchased it before passing it on to me. There is no halyard set up, nor cleats for the halyard or sheets. My question is thus, to those of you that fly a spinnaker:

1. Where do you mound your cleat for the halyard? Mast or deck? port or starboard side? I know the measurements call for the top block and wisker pole to be at a specific height, so that question is already answered for me.

2. Where do you run your sheets back to and where and what do you install this hardware?

3.Do any of you use a topping lift or downhaul to keep the wisker pole in place?

Hi:
I have been watching ebay for a used spinnaker for a DS1. I don't need one that is class legal - just something for us to fool around with. I have seen one from a Widgeon which is smaller that that for a daysailer and some for Lasers and Lightnings and Hobies - which are a foot or two larger or smaller in the foot than that for the daysailer. Does anyone else use one of these spinnakers on their daysailer? Is there anything in particular that I should look out for?
Thanks,
Joseph

If you are going to just fool around with one, I would go with one that is a bit smaller rather than larger. That way you won't have any issues seeing around a bigger sail and won't run into any compounded problems if you were to be hit by a nice gust.
Although, the extra sail area could make for an exciting ride.

Just make sure the clue/guy grommets aren't too low for the mast ring. You want the pole relatively horizontal.

I'm considering putting my mast ring on a track so I can use a bigger chute when I want .

There is a mast ring with a 25 inch track listed on ebay right now. Do a search for "spinnaker" and it is in the results.

Hi:
I finally won an auction for a cheap spinnaker on ebay. It is from a Lightning so it is a little bigger than the legal size for a Daysailer. What I need to know is how far apart I should position the spinnaker halyard block from the pole ring on the mast. Is there distance based upon the measurement of the sail?

The Lightning class rules are not as specific regarding positioning of the halyard block and pole ring as the Daysailer rules. They do not list measurements for these components in the rules at all.

Thanks,
Joseph

The placement of the top halyard block is 15' 3" above the bottom of the mast, and the whisker pole attaches 48" up the mast from the mast base, therefore the top halyard is 11' 3" inches from whisker pole ring. Now we already know that the regulation spinnaker for the DS is 16' from had to mid foot, so assuming that to be 100%, just apply a rule of percentage to get a similar height. You will have to insert the head to mid foot on your auction spinnaker, then apply the rule. Convert all your measures to inches, so 11' 3"= 135" and 16' is 192" so 192/135 gives you a ratio of 1.42

Measure your head to midfoot on your acquired sail and multiply by 1.42. That will give you the distance in inches from the whisker pole ring to the halyard top block. You already know that the ring should be at 48" so just add 48 inches to the derived figure and you have the placement point for your top block above the mast base.

If the foot of your acquired sail is also longer than the standard size use the same principle to determine how much longer than the standard 74 inches your whisker pole should be.

Remember that you whisker pole should always be horizontal so that both clew and tack are the same height above the deck. That is the quiding principle behind using the percentage formula to determine top block height.

Let us know how it works out for you.

Thanks Roger:

I don't know why I didn't think to do that. You inverted your ratio at the end but I understand what you meant - the distance from the pole ring to the spinnaker halyard block should be .70 times the distance from the head to mid-foot of the sail. I got the whisker pole length from Lightning rules as 6'10" - The sail hasn't arrived yet so I don't have the head to mid-foot measurement. It will be interesting to see if the ratio of spinnaker size between the Lightning and Daysailer is the same as the ratio of the pole sizes.

Since we are talking about non-legal spinnakers - would there be an advantage or disadvantage to mounting the pole higher or lower than the Daysailer specs and adjusting the height of the halyard block accordingly?

Thanks again,

Joseph

The higher you mount the whisker pole the higher you can mount your top block, but I suspect the higher you go, the more pitching and rolling you will experience in a downwind run, and more heel in a reach. The lower you can mount your 'power' the greater the effect of the sail as your boat stays more upright and trim. You don't want your boat plowing the water in a nose down trim, simply because the center of effort of your spinnaker is so high. Also you don't want to crank your mast off at the hounds because of all the pull at the mast top where it is not supported by shrouds!

Alternately, the theory goes that the higher you go, the greater the wind power, but somewhere there must be a trade off of lost power due to heeling.

The other item to keep in mind as you install a top block for a spinnaker is whether or not down the road, you plan to use a DRS (Drifter Reacher Spinnaker or Asymetrical spinnnaker. These are usually huge sails to take full advantage of the height of the mast and length of the boat to maximize sail area in really light winds. If for instance when you get your spinnaker and do your calculations, you find that you are only 18 inches or so from the mast top, you should go all the way to the top so that down the road you could use a drifter. I have a used drifter on order (haven't measured the head to midfoot yet) and I haven't fitted it to the mast yet, but from some basic trig, knowing the leech, luff and foot lengths, I will likely need to have a top block at the very highest possible level on the mast.

I note from your message that the whisker pole on a lightning is only 8 inches longer than on the DS. It will be interesting to test these ratio theories.