Boom preventers and vangs.

[AdriftAtSea]

Does anyone have a Spinlock PowerVang for sale?  I'm interested in getting one, but Spinlock discontinued the product back in September, and I haven't been able to find one for sale anywhere.   If you see one for sale, please let me know.

[AdriftAtSea]

I just installed a Dutchman Boom Brake on the Pretty Gee.  I've written about the installation and posted the story and photos on my blog, and you can read it here.

Although the Pretty Gee is a trimaran, the installation should work quite well on almost any sailboat with a similar chainplate setup.

Let me know what you think. 

Dan

[Zen]

Looks like a very clean setup. I'd be interested in hearing how it works.

I missed getting a dutchman brake system on ebay by $1.00, Arrrrrr

[AdriftAtSea]

I'd be happy to tell you how it works out, now that it is all installed... now, if only the weather would cooperate. :D  10-15 knots out of the west would be ideal... that's what I think we'll have tomorrow.

[Fortis]

One more point on preventers and the ropes used in them. A little bit of give is actually good, so using a nylon or other "stretchy" rope is ideal. There are a variety of hi-test stretchy ropes available and the one we use is a climber's dynamic rope in 12 mm. Being a climbers rope it is also of different colour and feel then anything else that leads back to the cockpit, so we are always sure of what we are dealing with. We use 12mm...which is probably overkill...but is very pleasent on the hand.

I crewed ona 36foot race boat last year where every rope on board (sheets, halyards, vangs and cunningham) was 5 or 6 mm spectra. Sail a race, throw away a pair of gloves and go looking for band aids and hand lotion. Really harsh way to a save a little weight aloft!


Alex.

[AdriftAtSea]

12mm may be a bit overkill for most of the boats used by people on this site... after all this is a small boat site... My boat, being a trimaran probably has greater issues, as my boat doesn't really heel to spill the wind from the sails.

Going with too small diameter a line, however strong it may be, is also a mistake.  Small lines are far more vulnerable to chafe, and much harder on the crew's hands.  Lines that are used often should be 3/8" minimum, preferably 7/16" or 1/2" if possible.  The sheets on my boat are all 7/16" or 1/2" line. 

Thinner lines are also harder to grip and handle, especially if your hands are cold.  Being harder to grip securely, makes for a more dangerous boat... imagine the amount of problems you can be in if you are trying to uncleat a mainsheet and your hands slip off the sheet before you get it uncleated... you could capsize the boat pretty easily in such a situation.

Had something like that happen last fall, and it was snowing that day, so not a great day to end up in the water.  Part of the problem was that the cam cleats weren't really properly maintained and were sticking, and part of it was that the line was too small to get a solid grip on in the cold, with gloves on... and part of it was the cockpit of the boat was lined with ice...so my feet ended up going out from under me as the boat heeled, and I had problems getting the sheet freed from the camcleat.  It worked in the end, but I was on my butt in the bottom of the cockpit when I finally freed the main.   

[Fortis]

7/16 IS 12mm


25mm equals one inch.

[AdriftAtSea]

7/16 IS 12mm


25mm equals one inch.

Actually, 25.4mm = 1 inch... and 7x25.4=177.8   177.8/16= 11.1125 

12 mm is closer to 1/2" than it is 7/16", which is a bit overkill for the preventer on most boats the size on this board.

If you're going to be picky about measurements, please use the correct ones at least.  Being so picky and using the wrong conversion factors just shows your ignorance.

[Captain Smollett]

Well, let's all calm down.   ;D

12 mm is close enough to halfway between 1/2 and 7/16 that an arguement over the issue pragmatically pointless.

12 mm / (25.4 mm/in ) = 0.472 in  (to three significant figures)

1/2 in = 0.500 in, or 0.028 in more than 12 mm.

7/16 in = 0.438 in (to three significant figures), or 0.034 less than 12 mm.

Halfway between 7/16 and 1/2 in would be 0.469 inches.  This makes 12 mm only 3 thousanths of an inch, less than a human hair, different from halfway.

[Zen]

I got a boom brake this weekend from the Marine swap meet, it came already with a large line that was comfortable to hold and small enough to cleat :)

[AdriftAtSea]

Well, let's all calm down.   ;D

12 mm is close enough to halfway between 1/2 and 7/16 that an arguement over the issue pragmatically pointless.

12 mm / (25.4 mm/in ) = 0.472 in  (to three significant figures)

1/2 in = 0.500 in, or 0.028 in more than 12 mm.

7/16 in = 0.438 in (to three significant figures), or 0.034 less than 12 mm.

Halfway between 7/16 and 1/2 in would be 0.469 inches.  This makes 12 mm only 3 thousanths of an inch, less than a human hair, different from halfway.

I do understand that the difference between the two is pretty neglible... I just dislike being lectured by someone who doesn't have their facts straight... The brake line on my boat is 3/8" just for the record.

Hey Zen-

Congrats on the purchase... if you have any questions, let me know. :D

[Captain Smollett]

I just dislike being lectured by someone who doesn't have their facts straight... The brake line on my boat is 3/8" just for the record.

Well, you can choose to interpret his comment as "lecturing" if you wish.

You stated in YOUR post use 7/16 but 1/2 is preferred, after writing that 12 mm was overkill.  He was pointing out that 12mm is BETWEEN those two (that you were recommending) and as you also later pointed out, is slightly smaller than than the line you said one should use.

I think the point he was making was how can 12 mm be overkill if 1/2 in (which is slightly larger) is recommended.

The bottom line is that each of us uses on our boats what we think is best.  There is no right or wrong MOST of the time.  Heck, I once used a crappy old trailer winch line (complete with rust stains) as a boom preventer.  Sometimes we use what we have available when the need arises.

The idea of SailFar, if I may speak for Kurt, is to exchange ideas and experiences.  Calling someone ignorant is not really conducive to such free exchange.  We all have something to offer (well, at least I HOPE that I do :) ).

[AdriftAtSea]

You're actually quoting me out of context.   For the boom brake, I believe that 1/2" line is a bit overkill,  but for commonly handled lines I've gone with larger diameter lines, to make them more comfortable to handle.

The boom brake line on my boat, which is not often handled, is only 3/8".  The sheets, which are handled very often, are 7/16" or 1/2".   I do believe that for most boats in the small boat range, a preventer of 1/2" is going to be a bit overkill.  The Dutchman Boom Brake, which I am using, recommends lines of 3/8"-7/16" for sails up to 500 sq. ft., which is considerably larger than those on the boats we're discussing.   

Most boats in the 20'–30' range will have mainsails less than 250 sq. ft.   They recommend lines only 1/4"–5/16" for sails of that size.  I made the decision to get the larger boom brake, as my sail is quite near the top end limit for the smallest model, being 242 sq. ft., based on their recommendation that you go up a size if you intend on going out in any heavy conditions or on very long passages. 

[Fortis]

Oh yes, I can tell Drifty and I are going to get along famously.

If you believe I was lecturing you, then it is only because you have not seen me in full blown pompous glory as I hold forth on sundry issues that the common masses cannot seem to encompass into their meagre collective wisdom.

And I do not think I read you out of context when, as Cpt Smollet points out, You went from calling my 12mm overkill after I ststed it was mostly that size for comfort-on-the-hand issues and then stated exactly the same thing to identify the same size rope in Imp. measurements as being ideal.

I am indeed ingorant about a great many things, and every day learn more about things that I know nothing about....But I think I am pretty solid on my metric/imperial conversion table.
Though farenheit tempretures make no sense to me and I find it easier to go from celcius to kelvin to farenheit then just between the two.


In short it was not my intention to lecture you, or influence your own choice of rope, for that matter. Given my whithers I would far prefer that people who read my post took away the info about considering dynamic or "stretchy" line for preventers then what size I find ideal and comfy. I am sure they can read a spec stress chart at the rope shop as well as I can.

Good day, sir.

Alex.

[Auspicious]

I have this long hunk of rope, y'know? I tie one end to the boom with a knot-thingy and run it up front on the boat and than back to the other end where it is tied off.

12mm double-braid, the LEAST stretchy stuff I could find. Someone with lots of miles (Evans Starzinger I think) made the point on another board that if you hold the boom stable then shock loading is less of an issue. I think that's a good point, so I set up my preventer with the minimum amount of stretch I can.

I use a bowline to the boom end (end-boom sheeting also). It's soft, easy, and doesn't jam. Some people have given me grief about not using a shackle "to make it easier to undo in an emergency." Frankly, if I'm using a preventer the boom is way out over the water and there are much better ways to get it off than climbing out there.

In an emergency, I'll cut the preventer at the forward shrouds (about where it comes in reach on my boat). If I have to I'll cut the return length anywhere along the deck. I'd rather not do that if I can avoid it since it leaves line in the water that can end up around the prop.

I run the line from the boom end forward, through a bow cleat and back along the deck to a stern cleat where I cleat it off.

To gybe, I release the stern cleated end, center the boom, gybe the boat, and let the boom out. I do have to go forward to rereeve the preventer for the other side, but downwind on my boat that isn't a huge concern.

I have seen people using this approach put a ring and shackle in the preventer near the mast, so you don't have to go all the way forward. That improvement is on my to-do list along with all the other splicing chores I have piling up.

Nothing like sitting in the cockpit at sunset, a glass of wine, a good companion, heaving on a g*& d&*%ed fid trying to get a double-braid eye splice to close all the way.