Jumper Shrouds

[KaiB]

I can't seem to find an answer to this question.

In general, do the jumper shrouds serve to stifen the mast, or they used to induce a bit of negative (forward bend) to the center third of the mast. this seems redundant as either the forestay could be tensioned up, or with the wire luff, a strong cunningham could do the job.

On the DS-1 I understand that they could be tossed, but where else could we hang our flying flamingo "Joe". (And I keep wondering why we point better to port)...

Kai&Audri
"Sadie B"
DS-1 #3162

[Peter McMinn]

I don't have the "jumper" shrouds you mention, but I've seen them on other boats. My understading is that they were an early attempt at doing just what you've guessed. However, I've been told that most of these are ditched as the concept doesn't quite pan out.

Better pointing on one tack over the other could be the consequence of any number of things. Maybe Joe's contributing somehow.

[KaiB]

I'm sure he's at fault...but what's sailing without a 3' flying pink flamingo?

I should be working, but here I am trying to learn dynamics and trying to understand the nuances of mast bend.

When we were young, we just went sailing instead. Hmmm....

[Roger]

Where were the original jumper shrouds attached?

[calden]

You can see the jumper shrouds here (click to enlarge):



The jumper shroud spreaders are right next to the upper "DS" on the sail. The shrouds go from about the mast top down to mid-jib or so.

Carlos

[KaiB]

We gottem...I'm trying to answer the mast bend question, i.e. do I want the shrouds to induce a bit of "pre-bend" forward.

I am coming to the conclusion that the answer is as variable as the set up on a guitar might be..."do what's right for you". A new set of North sails will react differently to static tensions than the older set we are currently sailing.

I love this site.

It will be 110 here today, little wind - so much for getting out and playing (altho the thought of water sounds good).

[Peter McMinn]

Had a little more time this morning to find the following discussion. Much of it has to do with tapered masts, but you might find some tasty tidbits:

http://forum.daysailer.org/forum/viewtopi ... 319c47c00b

[PDuckX]

My boat (3056) has the original mast with jump shrouds and quite frankly I don't have enough experience to know if it makes a difference or not. When I was down at the memorial day regatta in Eugene, Phil Root mentioned that many people that have those masts have taken them off. I believe it allows the mast to flex a bit to get a better sail shape.
Maybe someone can speak better to the facts of doing this.

[KaiB]

Andy, methinks you've hit the nail on the head.

I think one would have more varied control without the shrouds; the use of the jib halyard and or a cunningham in conjunction with total tension at the spreaders would allow fine tuning for changing wind speeds.

This leaves me wondering if the sailmaker would alter his cut knowing if a particular mast was stiffened by the jumper shrouds or not.

Can't sail, don't want to work, too hot to varnish, way too much time on my hands. Must learn to splice.

Kai & Audri
"Sadie B"
DS-1 #3162

[jpclowes]

If you are new to sailng, you probably want the upper stays off. Removing them makes the boat more forgiving in a blow, by allowing the mast more bend in a gust, thus giving some "shock absorption" when a gust hits, and giving you more time to release the sheet before healing too far over. Also the mast is stiff enough (at least mine is) that it won't flex much in light air, and the removal of all that weight at the top will make you faster too.

[KaiB]

Not new, but rusty...

I'm told I was made during a typhoon some 50 miles off of the Japaneese coast (Dad was an Army officer during the occupation in '53; he and mom lived aboard "Kitten") I haven't sailed dingys since my teens, and haven't sailed at all since I crewed in the Adriatic in the '80s.

We haven't had any issues sailing the little DS, but I have yet to gybe in a good Oklahoma breeze. I hate wet sandwiches.

Cheers,
Sadie B
DS-1 #3162

[Phill]

The upper jumper stays on the Alspar (untapered) mast, serve no usefull purpose, and may make the boat more unforgiving to sail. Most of us who race have the older tapered masts, or have purchased tapered masts. If the racers, who want to get the most power out of the rig, use tapered masts, why should any of us keep the upper jumper stays, that stiffen the upper mast of an already stiffer upper section that is not tapered? As mentioned above, the DS will be easier to sail in a blow and more effeicient.

With the above said, I raced an Alspar untapered mast for about 6 years, and would still be happy to use it, If I hadnt broken it when I crossed masts with a 26' footer, trying to hand out Lollipops to him between races.
I did remove the upper jumpers and the little forward reaching spreaders. I was lucky enough to win a Pacific Coast Championship and a High Serria Regatta, attended by many Nacr Champs, with that untapered mast.

Hope this helps. just my .02 cents worth

phill

[KaiB]

wise words indeed, thanks Phil...

When I order sails this fall, will my sailmaker want to know that the shrouds have been removed?

I remember that you use a rope luff on your jib. Does this mean that you rely on the forestay to provide forward tension on the rig, or is your system beefy enough to tune with the luff?

Do lollipops really make you go faster, flater, further?
Can a lollipop read a wind shift earlier?

[Peter McMinn]

I can tell you that that lollipop does!

[Phill]

If you order sails from one of the main builders, Jotz, North, Cressy/Doyle, I believe they will be cut generaly for the tapered masts. So I dont think any accomodation for a straight mast without the jumper stays, would be necessary. When I bought my first set of sails from Jotz (1992) I mentioned that I had the untapered Alspar mast. He said his sails worked on either mast with the same cut. My racing seemed to prove that out. 1994 PCC 1st. Then I replaced the bent Alspar, 1996, I continued to use that same original set of sails for 4 more years on a taperer mast, and won 2 NACR and 1 PCC with them. (Please forgive the boast, I only want to make the point that the sails work well on both kinds of mast) I used that same set of sails in a local regatta last weekend. I only use my best set of sails for top regattas, and that way I keep them competitive for about 5 -7 years.

The Jibs I use do have a small diameter rope in the luff instead wire. Originally it was because that was how the jibs came from the builder. After using that simple system where the Jib Halyard is used for the cloth tension and the forestay tensions the rig and jib sag, I found that it worked well enough that changing to an adjustable jib luff wire and adding a jib cunningham didnt make sense for my boat. To make this jib system work, a 3 or 4 to 1 purchase is needed for the jib halyard to get enough luff tension. Most of the rigging systems on my boat were the simplest I could come up with, and I would then see what the 'Big boys" where doing and I would copy them. Over the years, very little has been changed. Just a minor tweek here and there.

Lollipops make the crew (my kids) happier. you know what they say about a happy crew. However........ handing them out on the water has cost me one mast, and numerous dings, including a big side scrape from a Laser last weekend. As far as reading wind shifts, I leave that to me crew, I am always busy trying to keep those darn yarns flying on the jib luff.

phill

ps. I have no affiliation or deals with any sailmakers.