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Discussion Starter · #1 ·
I apologize for what seems to me to be a ridiculous question but we have never had a chance to actually fly the sails on our boat prior to her restoration. I am in the process of designing a cockpit arch that will double a s support for two solar panels and am very curious as to how the boom will clear these items. Perhaps this cannot even be answered but my question is, in normal use with normal sail geometry and cut, do you see the angle between the boom and the mast go beyond 90 degrees? My mind says no because any time I have sailed the sail shape seems inclined to draw up the sheeted end of the boom. We will have a gallows to cradle the boom when not in use for sailing but I want to see if I can pin down whether we will have the clearance during a tack or gybe as the boom sweeps across the vessel. I know the obvious answer here is to rig everything and measure but we really don't have this option right now so if its obvious that the angle remains acute and not obtuse than we will be in good shape. Any help here is appreciated.

Also, I've asked this before but wanted to reiterate: there is no reason why the main cannot be drawn all the way up to the top of the mast head, almost in contact with the sheave, correct? We have a sliding gooseneck and downhaul so luff tension can be accomplished a number of ways. Thanks all!
 

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Yes, it will sometimes- when you really trim on, you can open the angle up more, but it really depends on the boat and how your main is cut (which it seems you may already suspect). I've installed a bimini on our Olson 30 and don't use it often because of that same reason, and only in light air. Is there any way you can do a dry run- trim your mainsheet hard with the boom centered, then take your measurements?
 

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the word on the street is the angle is just shy of 90

88 to be exact...so to be safe design the gallows at 92-95 degrees or something so that you have some space...

yes sometimes when sheeting in real hard on an upwind leg its possoble to stretch out the main by hauling in too much...you can for sure get the boom greater than 90 degress...so give it some space to be safe...regards the mainsail going up enough

haul up the main till it stops then adjust the gooseneck height and luff tension...thats kind of the standard way on those adjusteable gooseneck type of boom setups...(you must have your rig tuned though, with correct rake)

cheers

the easiest way to design the gallows would be to look at other boats and boom height distance...

google image boom gallows and i BET youll get a lot of ideas...however to be safe you should first at least raise sails with a tuned and correctly raked mast before slapping on some gallows, unless they are adjusteable which is another option to consider...

you could make them height adjusteable.
 

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Pictures pictures and more pictures! get better answers!


The main sail needs room to stretch, why there is sometimes a good 6-10 inches to the sheave. Also, there are times when we want the boom to actually drop into the cockpit to work on it.

Arch for the panels.... Have you considered "windage" on such a set up? I just can't help but wonder about that much horizontal surface area over the stern of a very pretty boat.
 

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These angles change considerably when you reef. If I were you, I wouldn't build anything until I'd sailed the boat a couple of dozen times, in various conditions, reefed and not. On each point of sail take measurements and see what you've got. What are you going to do about a topping lift/vang?
 
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When you drop the main the boom can drop a bit unless you have a topping lift on.
This can also happen when you reef.
Your boom gallows wont help when reefing.

I think you need clearance. How much, I dunno.
Take the boat out and try it. try doinig it properly, then try doing it poorly, and try without the topping lift. Try reefing in a bit of wind and stuff it up totally - thats the way I do it at the best of times :)

It you have a ridged vang it will help, or should help.
 

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Gees, CaptA, I must be typing slowly these days...
 

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This isnt going to be a simple straight forward reply .....

Sail dimension data base listing for a Seafarer 34 (sloop or yawl) has that tack angle at 88° and a luff dimension of 36.0 ft. However this implies a properly/perfectly raised mainsail, if the mainsail has a luff boltrope (a 3 strand dacron rope inside a sleeve). Measure this tack angle - from the top of the boom to the mast. Additionally however, this 88° will be the for the boom being at it HIGHEST position from the cockpit / cockpit gear. .... the boom can get lower during normal sailing. This assumes that your mainsail was cut to the exact boat data base specifications and NOT a used sail from some other boat!!!!!!!!

Caution - This 88° is the 'as designed' tack angle ... without normal overtensioning of the mainsheet which will cause that tack angle to increase; not for an older sail whose boltrope has become shrunken due to age and usage which will cause that tack angle to also increase. ... this also implies that when raising a boltroped mainsail that the luff boltrope is properly and additionally 'stretched out' by approximately 1" per 10 ft. of luff length = 3.6" additional stretch after raising to 'just up' - the proper but relatively unknown way to 'raise' a dacron mainsail that has a boltrope.
If this seems complicated and confusing, go to the head of the class !!!!!

Suggestion: allow an additional 10° of tack angle so that your geometry isnt 'locked in' so that when the sail naturally changes its dimensions due to age, or overzealous tension on the mainsheet, etc. that the mounted gear doesnt become an impediment to the boom. 88° + 10° = 98-100° (approximate) ... maybe.

• raise the present mainsail but 'just up' and without any normal stretch out of the luff ... 'just raised up'.
• check the angle that the top of the boom makes with the mast is near 98-100°
you can cut a large sheet of cardboard to this 98-100° angle and use it as your 'guide' for setting the boom position.
• if that 100° tack angle (top of the boom to mast) provides sufficient clearance for the boom then 'use it'.

A properly raised boltroped mainsail ... by additionally and properly stretching out the luff by and addtional ~3.6" after raising 'just up' for your Seafarer will cause the aft end of the boom to be HIGHER than that 100° angle and the 'as set' tack angle will be closer to the 'as designed' 88°. If you use that 100° recommended 'imaginary' tack angle youll probably have sufficient clearance for most normal sailing operation - a high probability of 'maybe'.

IF the mainsail does NOT have a boltrope at its luff; and instead has a (rare) 'Taped' luff - many layers of folded dacron Tape at the luff, then get back to me or PM me for further discussion.

What Im driving towards here and a discussion of the 'foibles' of raising a mainsail that has a 'boltrope' - a 3 strand rope inside a sleeve at the luff, the most common configuration for woven dacron mainsails used for 'cruising' - a discussion of this 'anomaly' can be found here: How to properly RAISE a woven dacron mainsail - SailboatOwners.com see post #1. This extra stretching of the luff causes the aft end of the boom to RISE. If the sail is not PROPERLY raised, the aft end of the boom will or can be MUCH LOWER.

I hope I havent made this discussion TOO confusing; but, if your measurements dont include these 'anomalies' you may become 'locked-in' to a quite bad geometry that can easily prevent 'good sailing' and the natural swing and height of the boom. ;-)
 

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Discussion Starter · #9 ·
So there is good news and bad news in the replies, and thank you for all them. This is a live aboard vessel and as such we are relying on these panels as a primary source of energy. I wish they were smaller but it is what it is, they are 24v/280W and measure 3.5' x 6'. I had and continue to hope that they would actually act as the top to our Bimini with the side being the only cloth utilized. I too do not want to spoil the vessels lines but what other options do we have? A wind turbine would be nice but I don't want to deal with expense and noise, these panels seemed like safe, reliable, and silent bet, although now I may reconsider. I wish there was time to get this boat all ready for sailing and to tool around but we are hoping to board her and set off down the coast, so I will take your advice into consideration and probably play it safe and not build anything that can't be adjusted. I would be lying if I told all of you that the demands of making this project and all its complexities work are starting to drive me a bit nuts. The arch is not going to be in the way of anything so that can still go up but I will not put anything under the boom for now, back to the drawing board to see just how much clearance we can accommodate. Thanks gang, if you have any other advice do not hesitate. Quality affordable wind turbine anyone?
 

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Discussion Starter · #10 ·
Rich H, let me digest all of that. I have a new sail that does not have a boltrope and an older sail that does. To boot the two sails have different luff dimensions that I will remeasure this evening as I cannot find what I initially wrote down. I know a boltrope would a good item to add to the new sail, from what I have read. I really just want to go sailing at this point, I am typing this as my poor girlfriend wines away with the DA sander outside, I better get back out there or I'm in for it. Be back soon with more info. Thanks
 

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Please describe the sail material for the new sail - woven, high aspect woven, laminate with 'taffeta' overlay, vectron/mylar etc. and exactly how is the luff constructed???? luff dimension is not important as we have the approximate luff length - for 'good enough'. ;-)
 

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. I too do not want to spoil the vessels lines but what other options do we have?


Quality affordable wind turbine anyone?
On a live aboard boat or a cruising boat, especially for a long range cruise the lines of your boat come a distant 189th place to cold beer, frozen meat, and autopilot power...

max the solar and add wind if you can.

I have been looking at a wind generator thats under $1,000 with its own regulator... and that price is in the Caribbean so should be cheaper in the USA...
Caribbean's Leading Chandlery - Budget Marine
 

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Boy do you have that right ..... cold beer and frozen meat 'rule' but do require all that 'crap on de back' instead of a 'clean' boat.

For sailing, that means the wind is blowing and a wind gen is at its best. For anchoring it usually means that youre in the wind shadow of something or other (usually an island, etc.) and panels are best.

I HATE 'crap on de back' as its just more stuff to trip over and foul lines on and be in the way ..... and always at most inopportune time.
 

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Discussion Starter · #15 ·
Hey gang. Did some measuring last night and here is what I can tell you. It looks like the older sail is 4" longer then the new one, which is brand new. Total luff of 35' 8" on the old sail with boltrope being pulled by hand with tack tied to a tree. Do not know full material specs of new sail but to be honest I think this needs to be engineered with a lot of clearance, not an inch or two. At Full extension using the sliding gooseneck the downhaul the old sail will leave 1' between the base of the boom and the top of our panels, at a 90 degree angle. Turn that into a 100 degree angle and it just kisses the panels by my measure at the end of its 14' length. So, here is the question, I could not use the sliding gooseneck and pin it in a location about a foot and half above the panels and then use a standard downhaul arrangement with line and hook to tension the luff, like anyone else would do with a fixed mount gooseneck. The panels are something we really want and it looks like with this arrangment it will not be a proble. I will have an "arch" just above the penals surface with a delrin strip should anything go wrong the boom will not hit the panels. The new main on the otehr hand, before stretching offers a full 16" at full pull between boom bottom and panel surface, but we all know that the luff will stretch. Does anyone see an issue with what I have outlined. Also, if in light are and about to tack or gybe could we also not slacken the sheet a little more to get closer to that 90 degree mark and away from the 100 degree max we have determined. Thanks again for the help, I will look at the new main tonight and get a picture of the luff, slugs and design for your comments and what they were thinking with a boltrope. So to clarify, if I find a gooseneck height that allows clearance at 100 degrees of droop between the boom end and panels and pin it there then use the standard downhaul maneuver to control luff tensions we should be good. Alternatively one panels sits up front by the dodger, one panel on the arch, eliminating the center section where the boom ends THANKS!
 

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Sounds like a good plan. ... Sailing-wise, raising the tack by pinning the sliding gooseneck will only slightly increase the moment force that increases heeling. This wont be a problem as you'll just need to reef a few kts. of windstrength 'earlier'. ;-)
 

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Discussion Starter · #17 ·
Let me just ask this; with respect to my two luff lengths of 35'4" and 35'8" at what length from the top o the mast would all of you fix the gooseneck. I will be using a Cunningham arrangement for final luff tension so what would a normal slack be below said cunningham. The gooseneck is adjustable yes but not everyone's is so where would someone without this adjustment fix theirs to compromise between the two luff lengths? I do plan on drawing the sail all the way to the top of the mast almost to the sheave
 

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I will be using a Cunningham arrangement for final luff tension so what would a normal slack be below said cunningham.
WRONG ASSUMPTION !!!!! a cunningham is not connected to the bolt rope but ONLY to the luff sail fabric. Pulling tension on a cunningham will not affect - in anyway whatsoever - the length of a boltrope. The boltrope and how much its stretched, or not, will determine the 'actual' hoist length of the luff of sail and will directly set the height of the boom from the deck of the cockpit, etc.

Pull all the tension you can imagine on a cunningham and that tension WILL NOT affect the height of the aft end of the boom!
 

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Discussion Starter · #19 ·
so basically add 3-4" to the longer of the two sail luff lengths and that should be our gooseneck height, given your 1" stretch per 10'? I've gotten away from attempting to place anything permanent under the boom, too many variables, and I do understand your point with the boltrope. I'm just looking for rough dimensions now for other estimations. I will be sure and find all this out on the next vessel I purchase before purchasing, quite a hassle
 

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I have been looking at a wind generator thats under $1,000 with its own regulator... and that price is in the Caribbean so should be cheaper in the USA...
Maybe not. This looks like the same one, from Northern Tool.

Sunforce Marine Wind Turbine — 600 Watts, Model# 45446 | Wind Turbines| Northern Tool + Equipment

Northern Tool is a discount place, similar to Harbor Freight (if you've heard of them). In other words, you're probably going to have to work to find it in the U.S. for any cheaper than Northern Tool is selling it for.

Good luck.
 
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