How much mast rake do you have? (Standing rigging tuning)

goldenstate

Member III
Blogs Author
I am in the process of tuning new standing rigging for my boat.

I understand it is typical for masts to be bowed towards the rear of the boat. I understand the concept generally. An experienced boatyard guy said my mast should deflect about 3" at the apex of the curve, midway down the mast. (If I pull a line from the masthead to the deck, at the midpoint of the line there should be a 3" space between the line and the mast.)

I have all of my shrouds and stays pinned in. My current stumbling block is the topping lift arrangement. With my old rigging, the boom was level with surface of the water when the lift was in place. Now the aft end of the boom is about a foot too high. It looks like the boom is resting on my slip neighbor's boat, but it is not.

IMG_0212.JPG

Is my topping lift line too short? Did the rigging maker send me what I ordered?
Only way to find out is to climb the #@^@&@ mast, un pin the lift line, and measure it.
I did that this morning, and the line is about 1-2" shorter than I ordered, but that would not explain the 12" of line I had to add to make the boom level with the water.

So I am left thinking I haven't raked my mast back far enough.
Do I just need to tension the backstay more - perhaps release some tension from the forestay?

Ideas welcome.
 

Kenneth K

Sustaining Member
Blogs Author
I understand it is typical for masts to be bowed towards the rear of the boat. I understand the concept generally. An experienced boatyard guy said my mast should deflect about 3" at the apex of the curve, midway down the mast. (If I pull a line from the masthead to the deck, at the midpoint of the line there should be a 3" space between the line and the mast.)

I always thought this was a complicated one, so I hired out my mast-rigging job when I got my boat.

You can put both rake (tilt) in a "straight" mast, and then add bending to the top of the mast. Seems to me that "rake" (tilt) will be fairly constant throughout the length of the mast (and will require adjusting both upper and lower shrouds to change the rake). Bending, I think, occurs mostly above the upper spreaders and increases as you get closer to the masthead.

My rigger put a fairly substantial aft-bend to my mast (enough to cause slight ripples in the aluminum surface of the upper mast), though the lower ~80% of the mast is fairly vertical (un-raked).

It seems unlikely to me that you would see much curvature "midway" down the mast at you were told. Others will know more.....
 
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goldenstate

Member III
Blogs Author
I always thought this was a complicated one, so I hired out my mast-rigging job when I got my boat.

You can put both rake (tilt) in a "straight" mast, and then add bending to the top of the mast. Seems to me that "rake" (tilt) will be fairly constant throughout the length of the mast (and will require adjusting both upper and lower shrouds to change the rake). Bending, I think, occurs mostly above the upper spreaders and increases as you get closer to the masthead.

My rigger put a fairly substantial aft-bend to my mast (enough to cause slight ripples in the aluminum surface of the upper mast), though the lower ~80% of the mast is fairly vertical (un-raked).

It seems unlikely to me that you would see much curvature "midway" down the mast at you were told. Others will know more.....
Any idea how much farther back the top of your mast is vs the base?

4”? 10”?
 

Christian Williams

E381 - Los Angeles
Moderator
Blogs Author
Let's hope the topping lift somehow got too short.

But the mainsail hasn't changed shape, and when you hoist it you'll see immediately if the boom still hangs where it used to.
 

Kenneth K

Sustaining Member
Blogs Author
Any idea how much farther back the top of your mast is vs the base?

4”? 10”?
I've never measured it. I think it would take a plumb-bob or a laser to get an accurate measurement. When I looked at it once with a "swaying" main halyard pulled to one side of the boom, I think I could have convinced that anywhere from 4" to 10" away from the mast base was the "vertical" line.

Here's maybe the best side-shot photo I have (hard to tell if the camera was actually level, but the yellow horizontal line doesn't look too far off).

20180528_161301.jpg

The "bend" at the top I talked about isn't very visible in the photo. It becomes pretty apparent when you're looking up at it from boom level. What does surprise me is the amount of straight "rake" apparent in the photo. Compared to other boats in the marina, I always thought my mast was pretty much vertical. I don't see much bulge or "apex" in the mid-mast--it appears to diverge from vertical pretty proportionally moving from high to low--maybe only slight if any.

The pic above gives the appearance that the vertical line is about at the front of the aft hatch. That would be about 6" or so aft of the mast...20200803_152422.jpg
 
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goldenstate

Member III
Blogs Author
I've never measured it. I think it would take a plumb-bob or a laser to get an accurate measurement. When I looked at it once with a "swaying" main halyard pulled to one side of the boom, I think I could have convinced that anywhere from 4" to 10" away from the mast base was the "vertical" line.

Here's maybe the best side-shot photo I have (hard to tell if the camera was actually level, but the yellow horizontal line doesn't look too far off).

View attachment 35986

The "bend" at the top I talked about isn't very visible in the photo. It becomes pretty apparent when you're looking up at it from boom level. What does surprise me is the amount of straight "rake" apparent in the photo. Compared to other boats in the marina, I always thought my mast was pretty much vertical. I don't see much bulge or "apex" in the mid-mast--it appears to diverge from vertical pretty proportionally moving from high to low--maybe only slight if any.
Thank you, good feedback. I may try to loosen my forestay a bit and then cinch down the backstay - though I am fairly close to turnbuckle range on the backstay as it is.
 

goldenstate

Member III
Blogs Author
Let's hope the topping lift somehow got too short.

But the mainsail hasn't changed shape, and when you hoist it you'll see immediately if the boom still hangs where it used to.
Well, I've already gone up with my MastClimber and pulled the clevis pin and dropped the lift line.

Today was a good morning for it:

1605056754037.png

IMG_0216.jpg

The Colligo guys gave me within 1.5" of what I asked for, so I can't really blame them.

I measured a couple of times for my order (but of course now I've already recycled the old topping lift so I can't compare).

A topping lift is a "problem" that can be solved (at least in the short term) with some Amazon dyneema and a couple of bowline knots, if I can't make the Colligo one work. I hope I can rake the mast back and get the boom closer to the level at which I remember it.
 

Kenneth K

Sustaining Member
Blogs Author
Do you have a boom-adjustable topping lift (I thought that was standard on the 32-3). If so, can't you just lengthen the wire-rope side of the topping lift inside the boom?

Also, I've never done it, but I would assume that mast bend can be accomplished any time by adjusting shrouds & stays. Adjusting mast rake might also include moving the spacers in the mast-partners where the mast goes through the deck.
partners.jpg

Oh--I see you have a 32-200.....
 

goldenstate

Member III
Blogs Author
Do you have a boom-adjustable topping lift (I thought that was standard on the 32-3). If so, can't you just lengthen the wire-rope side of the topping lift inside the boom?

This is a great comment because it suggests that if indeed I have an adjustable topping lift, I have had my boat taken apart for so long, that I have forgotten how to rig it back the right way. And instead of climbing up the mast and removing the topping lift line, all I needed to do was to pull the topping lift adjustment line out of the boom, and attach it to my new topping lift, and be on my way.

#facepalm

Of course, I have an adjustable topping lift, and I have had my boat taken apart for so long, that I have forgotten how to rig it back the right way. Instead of climbing up the mast and removing the topping lift line, all I needed to do was to pull the topping lift adjustment line out of the boom, and attach it to my new topping lift, and be on my way.

At least I get another couple of practice rounds in with the MastClimber(?) Thank you, Kenneth. Too bad you weren't on the dock this morning pointing out my knuckleheaded-ness.
 
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Butch Bogan

Junior Member
This is a great comment because it suggests that if indeed I have an adjustable topping lift, I have had my boat taken apart for so long, that I have forgotten how to rig it back the right way. And instead of climbing up the mast and removing the topping lift line, all I needed to do was to pull the topping lift adjustment line out of the boom, and attach it to my new topping lift, and be on my way. #facepalm Of course, I have an adjustable topping lift, and I have had my boat taken apart for so long, that I have forgotten how to rig it back the right way. Instead of climbing up the mast and removing the topping lift line, all I needed to do was to pull the topping lift adjustment line out of the boom, and attach it to my new topping lift, and be on my way. At least I get another couple of practice rounds in with the MastClimber(?) Thank you, Kenneth. Too bad you weren't on the dock this morning pointing out my knuckleheaded-ness.
 

Kenneth K

Sustaining Member
Blogs Author
Hah! The facepalm only hurts for a few minutes, I happen to know from recent memory, but I'll take that any day over another 2-day, $180 project added to my list.
 

Butch Bogan

Junior Member
Sorry about that last reply, I was having some computer meltdown.

Anyway, not to sound too much like a know-it-all, but I have been a professional rigger for quite a while. It sounds like you may have figured out your topping lift issue, but I'm going to add my two cents worth and also comment on the rig tuning comments.

In my opinion it's always best to have an adjustable topping lift on boats over 27 feet or so. This can be accomplished with an in boom system that is usually lead to the forward end of the boom, or an external system on the side of the boom. On larger boats I recommend a second masthead halyard, parallel to the main halyard, that can be used as a boom topping lift or as an emergency main halyard. Of course you'll have to have two masthead sheaves to do this. The benefits of being able to adjust your boom height are not only to get it off the dodger/bimini, but also to take the load off the leach while putting in or shaking out a reef. If you have a heavy mainsail it helps to have a purchase system to ease the effort of adjusting, however, I've seen a lot of very crowded boom interiors, so it might not always be possible to go internal. This is just the tip of the proverbial iceberg, there may be other factors to consider, best to consult with a good rigger or sailmaker if you have concerns with chafe or structure.

Now, to the subject of mast bend and rake. Chapters have been written on this and I don't plan on being too detailed, please don't get me started. Rake, as someone mentioned earlier, is basically how the column of the mast leans from the step to the head. It is determined by the mast base and step and deck partners if you have a keel stepped mast. In rake alone the mast is straight, not plumb, but not bent. Rake can determine center of effort on the boats sail plan and affect your windward ability. Significantly changing the design rake of a rig will have dramatic effect on how the boat handles, I do not recommend this being done without some professional advice and much thought.

Now to mast bend. This is a pretty complex issue, but here goes. Bend is putting shape in a mast that takes it out of a straight column, again not to be confused with a plumb mast. If you have straight, perpendicular to the mast, spreaders and shallow angle lower shrouds, the only way to get bend is by adjusting the jibstay and backstay tension. If you don't have a backstay adjuster, to enable temporary tightening of the backstay, thus inducing bend when you want it, you need to be careful about how you tune your rigging. If you have a mainsail, or furling headsail, that was cut for a certain mast shape you can really mess up your boats performance by adding or reducing bend.

Please do not try to induce bend in your mast by just tightening your forward lower shrouds, unless you really know what you are doing. The standing rig is a complex system that needs to be well understood, the loads on a rig, mast, chainplates and other structure on the boat change dynamically. I have seen plenty of rigs bent into pieces of modern art by well meaning dock neighbors commenting on how "your mast needs some more bend there". Knowing how to properly tune a rig is part science and part black magic, tuning gauges are just a tool to assist with verifying tension, proper shape is the first step.

I hope this helps a little.
 

goldenstate

Member III
Blogs Author
Sorry about that last reply, I was having some computer meltdown.

Anyway, not to sound too much like a know-it-all, but I have been a professional rigger for quite a while. It sounds like you may have figured out your topping lift issue, but I'm going to add my two cents worth and also comment on the rig tuning comments.

In my opinion it's always best to have an adjustable topping lift on boats over 27 feet or so. This can be accomplished with an in boom system that is usually lead to the forward end of the boom, or an external system on the side of the boom. On larger boats I recommend a second masthead halyard, parallel to the main halyard, that can be used as a boom topping lift or as an emergency main halyard. Of course you'll have to have two masthead sheaves to do this. The benefits of being able to adjust your boom height are not only to get it off the dodger/bimini, but also to take the load off the leach while putting in or shaking out a reef. If you have a heavy mainsail it helps to have a purchase system to ease the effort of adjusting, however, I've seen a lot of very crowded boom interiors, so it might not always be possible to go internal. This is just the tip of the proverbial iceberg, there may be other factors to consider, best to consult with a good rigger or sailmaker if you have concerns with chafe or structure.

Now, to the subject of mast bend and rake. Chapters have been written on this and I don't plan on being too detailed, please don't get me started. Rake, as someone mentioned earlier, is basically how the column of the mast leans from the step to the head. It is determined by the mast base and step and deck partners if you have a keel stepped mast. In rake alone the mast is straight, not plumb, but not bent. Rake can determine center of effort on the boats sail plan and affect your windward ability. Significantly changing the design rake of a rig will have dramatic effect on how the boat handles, I do not recommend this being done without some professional advice and much thought.

Now to mast bend. This is a pretty complex issue, but here goes. Bend is putting shape in a mast that takes it out of a straight column, again not to be confused with a plumb mast. If you have straight, perpendicular to the mast, spreaders and shallow angle lower shrouds, the only way to get bend is by adjusting the jibstay and backstay tension. If you don't have a backstay adjuster, to enable temporary tightening of the backstay, thus inducing bend when you want it, you need to be careful about how you tune your rigging. If you have a mainsail, or furling headsail, that was cut for a certain mast shape you can really mess up your boats performance by adding or reducing bend.

Please do not try to induce bend in your mast by just tightening your forward lower shrouds, unless you really know what you are doing. The standing rig is a complex system that needs to be well understood, the loads on a rig, mast, chainplates and other structure on the boat change dynamically. I have seen plenty of rigs bent into pieces of modern art by well meaning dock neighbors commenting on how "your mast needs some more bend there". Knowing how to properly tune a rig is part science and part black magic, tuning gauges are just a tool to assist with verifying tension, proper shape is the first step.

I hope this helps a little.

Hi Butch -

Thank you for all of the feedback. My goal is to return my rigging to the state in which I received it, prior to my standing rigging replacement.

I'm interested in safe cruising, not optimal racing, and I don't think I had much if any mast bend to begin with. I'm not seeking any bend, I guess.

My hope is to get the boat out for a shake-down sail and then have a professional review my settings to see what I am missing.

-Tom
 

Butch Bogan

Junior Member
Hi Tom,

You're welcome. Mast shape and tune is kind of a big deal to me and there is so much mis-information out there.

If you have a new rigging gang you will have to get the rig retuned after you've set everything and sailed the boat a few times. Wire has what's known as construction stretch that needs to be taken out by loading up the rig while sailing. I tell my customers to go out a few times on a good wind day and sail close hauled for as long as possible to really load up the rig. After that you can get a final tune and for the most part forget about it. You're fortunate if you're in the Bay area as there are many good riggers around there if you need any help.

P.S. A properly tuned rig will make the boat sail better and safer whether you race or not. Racers have their own deamons.
 

Brad Johnson

Member II
I have a 1988 26 -2 which is fractional raged and I have fooled around with various rake positions, and what I found was rake aft helps pointing , rake forward helped speed, My boat is a little stern heavy so my experience with my boat is rake forward. as far as bend it is a must to match the luff curve that the sailmaker put in designing the main. I have about 4" bend normal and with a backstay adjuster and running back stays I can shape the main for many conditions. I do some club racing with mostly bigger faster boats so I over did it setting up my boat, my friend say I have too many strings !!!
 

frick

Member III
Im not a rigger, but just an old DYI sailor...

I would say that most mast head rigs need a little rake aft and not a bend in the mast.
When I think of a bend in the mast I think of the old 6 meter and 30 squares boats with a fractional rig and very visible bend.
The mast on my 1971 E29 is like a tree trunk. With single spreaders it realy want to stay straight, with a little rack to the aft.
Use your main halyard as your plumbob. You can also use it to check the distances say from the starboard and port chain plates, or stanchions. Why... because it is more important to have the mast centered on the boat so it perform equally on Starboard and port tacks.

When going to weather, how does the leading edge of the jib look? If its not very straight, title the back stay a little more.

My 2 cents
 

Christian Williams

E381 - Los Angeles
Moderator
Blogs Author
My mast is straight with a rake of a few inches. All a cruising boat cares about.

But forward rake is great for downwind, and hilariously apparent in any Star regatta. Or Soling, where with a flick of the wrist you dump the mast forward two feet.

A windsurfer demonstrates rake effect, since without rudder that's the only way it turns. Tilt mast forward, head off. To tack, haul mast all the way aft and the boat turns into the wind.

star .jpg
 

pmarsha3

Member I
Ive seen a whole lot of very good old boats scrapped simply because the crew put too much tension on the back stay and broke the mast. The cost of a new mast isn't justified.
 

p.gazibara

Member III
I rerigged with colligo rigging in Tahiti while on anchor, pulling my mast with another boat’s mast and doing the work on deck.

Buzz Ballinger made my rig which is 2” longer than a stock Express 34 rig.

He has a very good article about setting up/tuning rigging. He recommended 1.5 degrees of rake, I would imagine your boat wouldn’t be too far off. Colligo is pretty bad about getting lengths right, fortunately you can resplice it pretty easily.

You will know if the rake is right or not when you go sailing. Too much rake and she will pull to weather, too little, and she will fall off.

Your main should tell you if the bend is right or not. If you have a bag in the sail about halfway up, probably need to add more bend. If it’s too flat, remove bend. This should be controlled by the forward lowers.

Hopefully Guy can chime in at some point, he has rigged quite a few boats with dux.

-P
 
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