Nerdy Sail Stuff

[Dave R1]

Alright, I'll admit I buried the needle on the Nerd-O-Meter.

I just ordered new sails for Julie K and made some drawings to send to the sailmaker. I got to doing some rough calculating regarding the position of the reef row(s)

The Weekender main calculates out to about 88.5 sq ft. Reefed at various distances from the foot, it looks like this

22" up---69.9 sq ft

30" up---63.6 sq ft

36" up---59.0 sq ft

44" up---53.1 sq ft

I discovered that the sail plan dimensions don't quite work out right. If you use some of the dimensions, others don't match. They aren't too far off but might leave some scratching their heads. If anyone wants corrected drawings, I can send them.

[kydocfrog]

I would love to see them; either as drawings or at least as corrected dimensions.

DocA

[Dave R1]

How's this?

[Stump]

cool, thanks. 8) 8)

[Dave R1]

Stump, you're welcome. So do you suppose there should be a smilie wearing glasses with white tape holding them together and a pocket protector?

[capt jake]

So do you suppose there should be a smilie wearing glasses with white tape holding them together and a pocket protector?

You really don't want an answer to that, do you? LOL

[kydocfrog]

Thanks Much!!!!

DocA

[John Weigandt]

because.... you're gonna lay out the foot first.... swing up approx 80 degrees, but have your pencil or marker on a 118 inch string and mark not a point but an arc ... go to the other end so an arc on a 170 inch tether on the leech.. then fit the 68 inch dimension as best it can fit along the gaff top end of the sail using your protactor and either a 141 or 142 degree angle .. your choice. .

In the grand scheme of things over these distances, and with our small little protractors... the angle you end up with will be approximate anyway.

Now.. if you send to a sailmaker who's gonna produce a cad drawing.. OK the dimensions don't work.. but when this sail was first drawn.. circa 1980 Mere mortals didn't have such equipment available to them..

and puleeese.. 41/64 uh that's about 1/7 of an inch off of the designated 1/2 ... I'm surprised they got that close in the original. :-)

it also looks like you assume that is a right angle at the base of the jib... mebbe mebbe not.. . I'd have to go back to the original plan to see.

So shake your band aided knuckles against the wind.. Snort glibly through your swollen adenoids, push up those taped glasses with your middle finger, but holster that K and E sliderule before you hurt someone.

John

[Dave R1]

John, it sounds like my post kind of bugged you. Sorry. It wasn't meant to upset anyone. I know as well as anyone that those small variations in dimensions don't matter in this application. Those dimensions showing 64ths of an inch were generated by the software. I just left them the way the program reported them.

As to the jib clew, you are incorrect. I did not assume it to be square. The only angle I assumed was the 90

[kydocfrog]

No, you don't take them off. They are useful. I, for one, asked to see them, and I appreciate your posting. And a 4 inch difference on the jib luff is not insignificant. Might explain part of why there seems to be so much variation in the way jibs look in various photos.

Besides, in my copy of the plan book, some of the sail measurements are not readable - is that a 5, a 6, or an 8-- so I find these drawings useful. I appreciate both your curiosity in producing them to answer quesitons you had and your generosity in posting them.

DocA

[Barry Pyeatt]

I agree! Although the dimensions may not be entirely accurate they do help to identify some things to think about. The initial set of sails as far as I'm concerned are better off being made up of poly tarp and used to get used to the handling of the boat and to help find problem areas.

More importantly, as far as I'm concerned is not the specific dimensions on the sails as in the mast angle on the boat. It really doesn't make much sense to have everything else correct if that is wrong more than about one or two degrees off. Most of the major issues I've helped builders with that are having issues with handling and sailing have been due to the mast being anywhere from 5-9 degrees off from plans. All of them have had the front bulkhead installed with too much rake.

If the boom hangs down too low and there just isn't clearance for your brain cage, then having sails that are made to spec isn't the problem. Neither will raising the boom at the mast solve it. And having a main sail made to fit it isn't going to solve the handling problem either.

There have been many discussions on this and other forums about the sail area being sufficient for good handling. As designed it is just fine and the boat should handle just fine for the new builder if all else is built close to plans. There are a lot of Weekenders out there that handle just fine and bring a whole lotta fun to their owners.

I will grant that having a larger jib such as a Lapper will make a significant difference in how the boat will handle and how much weather helm it will have. In my experience, it becomes pretty well balanced in light to moderate air. But about the time it becomes necessary to reef the main, you don't want that large a jib. The stock jib gives you much better performance. Beyond that point in wind conditions, additional reefing points should best be coupled with a much smaller jib more like a stormsail. About 50% of the area of the stock jib.

Also there has been much discussion about loose footed vs. laced foots to the main. Differences in performance questions and opinions. In practice it really depends a whole bunch on what your particular sailing conditions are like "MOST OF THE TIME YOU ARE OUT". If they are virtually no air movement to moderate winds a loose footed main will allow you to really bag out the main and grab what is there when working off the wind. working into it you still need to flatten up the main to make it work well. IN moderate to moderatly heavy conditions a laced foot will make life easier especially when you need to reef down. The outhaul becomes essential to work with to adjust the tension on a loose footed main and to work well, the main has to have additional material (roach) cut into the foot of the sail. When flat this adds an additional 5-8 inchs of material below the boom when slack. This material is cut on a hanging curve and is designed to allow you to "bag out" the main by loosening the outhaul and thereby catch more wind, more efficiently. Result better very light air performance working across or down wind. Just not lacing the main to the boom as designed will not do that for you. Yes, you can adjust the outhaul to bag out the main as designed, but it really doesn't make much difference without having curvature built into the sail as well.

The jib on a clubfoot is a lot easier to work with while getting to know your boat, and really a lot easier to work with if sailing solo. It isn't a beginner/newbie way of sailing. There are tons of classic boats out there that use clubfoots on the jib. They work and work well once you learn how to set them and when to adjust them. Obviously if you want more sail area, you will need to eliminate the clubfoot and have two distinct jib sheets to manage. Also play around with block placement to get the best compromise as far as placement for your local conditions and way of sailing. This is tuning and it can be complicated, even for very experienced people.

One very simple thing to do with a jib and main sail if having them made is to have leech lines installed in the trailing edge of the sails. Some sailmakers do them as a standard item, most do not unless specified. This is a simple line sewn into the trailing edge of the sail that is fixed at the top and exits the seam at or near the bottom with a little jam cleat to grab the line. and allow you to shorten it or let it out. Its purpose is to shorten the trailing edge of the sail thereby causing it to be fuller (bagged out) and catch more air when it is very light conditions. The result is more air being captured by the sails and better performance. But when you head upwind and need to tack back and forth you need to flatten them both out again. This is also easy to do with homemade tarp sails if you are using a kit. There are instructions available to do this or even to modify existing sails to add this feature. And most builders that are new to sail handling will notice a distinct difference in performance. This is also a "tuning" trick.

I think the drawings Dave produced are good information for any of us but only a basic measurement that needs to be give to the sailmaker if you are having a kit made or custom sails made. Because they will know what changes need to be made in them to make the sails work for your experience and sailing conditions. It is rocket science, in a way.

Gaff rigged boats have become pretty sophisticated over their lifespan, but out of style and other rigs have become popular because they are easier to work with and don't require as much work to get good performance. But once you learn some basics about how to work with your own particular setup in your area you will get just about all there is to get out of this design.

I really don't recommend changing much from the designed boat until you know it. Once you have reached the limits of what you can do with it in your local conditions and at a level that you are comfortable with, then consider what might make it work better for you.

I've been out in open ocean with the Weekender in some pretty hairy conditions and it is a solid safe boat as designed and will give you great fun. As long as you know your boat and what to do when things get hairy. It is a long learning curve and just how fast you work your way thru it is going to vary considerably between each of us. Some builders will never get to the extremes of how well the boat will sail. They get too nervous about healing over and really don't know what to do when it gets windy. Better to have less sail area and learn to handle things well before you start changing things and not know what is happening or how to deal with it. These are great boats to have a lot of fun with and for those that have the experience already sailing, they can be changed and tuned just enough to make them outsail almost all of the other small boats in the same conditions and particularly when the others are just sitting and can't go anywhere without an engine running.

[John Weigandt]

Sorry y'all

I was trying to continue in the "Nerd" motif.. (pocket protector taped glasses etc) Sorry if the satire didn't come across.

The serious point I was trying to make though... was for any new builders ... The accuracy atainable on the garage floor is no where near what you can get on a cad program.

My first sails were of poly tarp (the quality stuff from Dave Gray) and served me well for several years. They got kinda blown out from use and abuse, and I had my current dacron ones made by a talented sailmaker who seems to have fallen off the edge of the earth (I really hope he's OK) and feel sorry for anyone who got taken for some money at the end.

anyway .. if you ever make me mad... I won't leave much to conjecture or doubt.. :twisted: :twisted: :twisted:

I agree that not everything is clear or probably accurate in the Weekender plans ( I still have a "short" forward bulkhead in my garage loft to prove the clarity problem.... or was it just me )

John

[Barry Pyeatt]

FWIW I got it John and actually got a kick out of it.

[kydocfrog]

Which brings me to a question.

The 80 degree angle at the clew, assuming that the boom should be generally paralllel to the plane of the water, seems to mean that the mast should be raked 10 degrees relative to the plane. But you can't measure that directly because of the sheer of the deck.

Does anyone have the actual angle that the rear face of the mast will make with the deck if all has been done well?

Maybe I should be able to figure this out from the plans, but I haven't

Thanks

DocA

[Barry Pyeatt]

It isn't measured against the deck. It also doesn't relate to the waterline as being parallel. The angle of the mast is determined by the measuring the front surface of the mast box to the bottom in front of the mast box. Since the bottom has rocker (curved upwards) it doesn't relate to the waterline or the deck accurately either.

To check it, using your angle keeper set it on the front of mast box and lock with the other edge against the bottom of the boat. (You will probably need to set a block the same thickness as the retainer around the bottom of the mast box to accomplish this.) Then using your protractor measure that angle on the angle keeper.

This measurement is taken 5" forward of the forward bulkhead and since the bottom is a curved surface the angle is slightly different at the front of the mast box as compared to the front side of the bulkhead. The angle should be 93 degrees at that point. If it is different, either less or more, your mast will either have too little rake which will result in less weather helm and more lee helm (The boat will have a tendency to turn away from the wind). If the angle is greater than 93 degrees, the boat will have an exagerated weather helm (The boat will want to turn into the wind more than normal.) In the later case the tiller or wheel (helm) will be harder to control and be more resistant to control movement. The boat will resist working away from the wind and feel more difficult to control as you are tacking.

Ideally we would have just slight pressure on the tiller with a nearly balanced helm. If you release the helm in moderate air the boat will turn into the wind and stop. The sails will flap in the breeze (luff) and you can take care of whatever you need to do.

If you have too little rake, the boat will have a tendency to turn away from the wind and the sails will keep driving the boat before the wind. Bad thing if you are trying to swim to catch up to it. :cry:

So if it is just a degree or two off, the mast may be able to be shimmed within the mast box to correct for it. If it is more than that then more dramatic changes need to me made to correct for it. If the rake is too much, the boom will hang down into the cockpit area and constantly be in the way as well. So simply correcting the mast rake will do several things. Just a few degrees off in a 15' length is quite a bit. Straightening it back up will of course raise the trailing edge of the boom significantly.

It will also reduce the weather helm (the tendency to want to turn into the wind constantly). We want some weather helm so that if we release the tiller or wheel, the boat will turn into the wind and the sails will luff in the wind and the boat will stop. Distinct advantage if something happens and we end up over board as an example. Lot easier to get back to a boat that isn't going anywhere. In heavier winds less weather helm will allow you to have better control without becoming overly tired from fighting the tiller or wheel constantly.

The drawings may help to see what I'm referring to as far as measuring it.

I've seen some Weekenders with as much as 112 degrees of rake and the boom hanging down to near the cockpit floor. The owner couldn't get the boat to tack or turn out of the wind without a major effort and couldn't tack thru the wind to a new heading. Totally frustrated with sailing. They had had a sail maker cut the main sail to help raise the boom. (Only it wasn't actually a sailmaker it was a friend that had a sewing machine.) The friend said it would take care of everything if the cut a section off the bottom of the main and raised the boom so that there was clearance. If didn't of course.

I've seen others more often that are 100 to 107 degrees of rake and they have essentially the same issues. But most of them also had too much rudder swing and the boat would stall when trying to tack. They would set the tiller over hard and try to tack. The rudder acted essentially like a brake and the extra weather helm would just keep it from going around. (Locked up (in irons) is the term.) Again the mast rake was first thing to correct and then stops on the rudder so it would only swing about 30-35 degrees either side of center.

[Barry Pyeatt]

If the mast does not have enough rake, you end up with lots of boom clearance but the jib seems to be too large to fit right and with the clubfoot it wants to drag on the deck. Often the builder will extend the bottom attachment point of the tack of the jib to raise it for more clearance. The jib then sets higher on the mast and it will then work with the clubfoot.

The boat generally tacks fine but will want to turn away from the wind with more pressure on the tiller or helm to turn away from the wind. If you aren't paying attention it will fall off of the wind rapidly. (Normally if you are not paying attention it would have a tendency to turn into the wind eventually. )

Correcting for a few degrees of difference doesn't require redoing the bulkhead or the mast box either. It does require some work on the tabernacle of the mast to create a bend in it. By creating an artificial bend at the deck level we can straighten up the upper portion of the mast and eliminate the small errors in the mast rake and everything will be fine.

This isn't all that complicated once we know just how far out it is from the 93 degree measurment. Say it is off 7 degrees and the angle measured is 100 degrees. We need to bring the top of the mast forward by tilting it forward by 7 degrees to create the 93 degree angle. We can't pull it that far with forestay tension and it probably won't bend that far either. So we cut a wedge off the the tabernacle below the deck level where it won't show. We cut this 7 degree wedge off the back side of the tabernacle and then reattach it to the front side of the tabernacle to create a bend in the lower section. (below the deck level).

No one will ever know since that portion above the deck will be at the correct angle and I'm not going to tell if you don't.

Obviously if it is different angle than that you need to cut a wedge the size you need to make up the difference. Yes, you loose the amount of material from the saw kerf. You can either use a thin strip of plywood or solid wood to make up the difference or just tack on a strip that thick to the bottom of the tabernacle front side before inserting it back into the mast box.

If it doesn't have enough rake you would do just the opposite to create more rake.

This will take care of a whole lot of frustration and make sailing a bunch more enjoyable when you get a more balanced helm . It also is a whole lot easier than tearing out the bulkhead and redoing it. It is a one hour job vs. who knows if it will ever get done.

I do know that those that have made the change have reported that they are having fun with their boats now instead of constantly fighting them.

A degree or two can be compensated for by tightening the forestay and shimming the backside of the tabernacle within the top of the mast box generally.

[Guest Oyster]

Funny, nerdy boat stuff? no way, not me, ever never ever would allow such things to enter my well orchestrated, well organized, and well planned and regimented routines, You guys ain't gettin close to me. 8)

[Barry Pyeatt]

Just wish I had your scrap lumber pile Oyster. And your talent for finding the places to get that scrap. Then I would just like to follow you thru an entire build one time in person. I could learn a bunch. 8)

[kydocfrog]

Okay, I see the 93 degree angle and how it can be used as a check on the basic construction. That's a start. (Going to be interesting standing on my head to check that...) I'm still not sure how everything actually works out.

The 93 degree angle is fixed relative to the bottom of the boat, but is not fixed relative to the presentation to wind/water etc which will change depending on the loading of the boat -- stern heavy, bow heavy, etc. All discussions of mast rake that I have ever seen assume that the rake is relative to the theoretical plane of the surface of the water as described by the normal load water line and, therefore it seems, to the presentation of the mast and sail to the wind. There's no other way to measure it. The box in the weekender is would appear to be simply a construction artifact peculiar to the design that will result in a particular rake. The actual rake of the mast still escapes me. (I sure hope it turns out to be 93 when I measure it. There's not a lot of adjustment available; sort of none.)

I was really looking indirectly for more information about the sail. Nothing in the 93 degree measurement of the mast relative to the rocker at that given point seems to directly account for the 80 degree included angle at the clew or allow one to verify it before cutting. Where's that number come from? If it makes the boom horizontal when the boat is at rest, then one would have to assume that the mast at rest sets at 10 degrees aft of basic plumb...a combination of the 93 degrees off the rocker and, I guess, three degrees induced by the rocker.

DocA

[Guest Oyster]

Thanks Barry, but anyone can do it, if you have some idle time. Take a trip around your local lumberyard, checking for twisted stuff, long boards that have twists and bows, say like the 16 footers that have been sorted through, tossed aside behind the piles, layed in the weather all greyed out, even the ones that are split at the ends, as most lumber is cut anyway. Keep in mind, the laminated process is done with cut pieces, too. Anyone can do it. Make offers to the folks. Take a sat. and tell them that you will restack the good stuff, keeping the piles from being sorted and rummaged through again. Don't be afraid to ask, or make them an offer on soiled pieces, or broken corners on culled plywoods, All they can say is no.