Mast Bend

[Scott2]

I bought my 2003 H240 three years ago, but have never been satisfied with the mast bend. It seems excessive and looks like a banana. My New Years resolution is to take most of the bend out.

As I understand the concept of the swept standing rigging on the boat, I should adjust the tension on the shrouds that run from the tip of the spreaders to near the base of the mast to increase or decrease the bend, however, I am right at the very end of the possible adjustment. I can not loosen them any more because I have no more threads left on the turnbuckle. I have two questions: 1) Are there other things I should be doing to take the bend out of the mast? 2) Can I safely rig the mast without the stays that run from the spreaders to the base of the mast if they are too short? Thanks for your advice and Happy New Year!

 

[Ed Schenck]

What?! Are you asking if you can remove the "uppers"? Those are the shrouds that cross the tip of the spreaders and go to the top of the mast. You need to get instructions for proper mast tuning. Try the Brion Toss website.

 

[Dan Hill]

The mast and sails are designed to use that bend as is. Why would you even try to remove it? If someone told you it shouldn't be bent they need to read your mast tuning instructions and study the workings of an B&R rig.

 

[Bill Roosa]

hey Scott
I have to agree with the others, your sail is cut to account for a bent mast. When you straighten it the sail will be baggy and you will not be able to flatten it prior to reefing. After reefing the sail will also be more baggy than before.

 

[Don12364]

Before we all squabble over this, could it please be established how much bend there is in this mast.
It is measured by pulling the main halyard down tight against the mast at the goose neck and then either measuring or estimating the distance between halyard and mast at the widest point.
Mainsails are cut with a 'round' in the luff and the mast bend needs to match this.
Also, if the bend is excessive, the mast could become unstable under compression and wind/sail loads.
Bend is not to be confused with 'rake' though both have profound effects on the way the boat sails.
And, to have taken up all the adjustment in the turnbuckles could indicate either too much bend or too much rake (or both!)
So Scott2 could you provide the details please?

 

[Dan Johnson]

Scott...

I had been a dealer for water ballast Hunters when the 240 was introduced, and rigged several masts myself upon delivery. Mast bend was set up with the mast down on sawhorses.

I don't recall the static dimension off the mast of a line stretched from the masthead to the gooseneck that is used to adjust the diagonals to achieve the proper bow.

However, with the mast raised, the distance of the mainsail halyard end should not be more six inches aft of the gooseneck at the boom level when hanging loose with the boat level.

 

[Allan12210]

Having the diagonals and a prebend in the B&R rig allows to use a mast with a much thinner section than a conventional straight mast. This means less weight aloft and a faster, less tender boat. The prebend then introduces a stress that must be overcome first with the force of the wind propelling the boat forward before the mast can bend forward. Remove the bend and the thin mast will bend forward, permamently. It is engineered to be that way and the sail is cut as Donalex says to fit that curvature. If a curved sail is hoisted on a straight mast, the luff isn't going to tension right until the sail is permanently stretched out of shape.

On the larger boats, the curve is 1% of the length of the mast from the top to the point where the lower diagonal comes back to the mast near the base. So a 50 foot mast would curve away from a string pulled tight by 1/2 foot or 6 inches. If it is an internal roller furling mast, that curve is no more than 2 inches.

 

[sesmith]

As mentioned above...mast tuning procedure here:

http://hunter.sailboatowners.com/index.php?option=com_content&task=view&id=35&Itemid=87

 

[Scott2]

Thanks for the posts everyone. To put some at ease, no... I'm not talking about the upper shrouds, I am talking about the shrouds that go from the tip of the spreader to the BASE of the mast. They form a diamond shape with the upper shrouds and do not touch the deck of the boat. No... no one has told me to take the bend out. However, it looks odd enough that other sailors have commented and it sure stands out in the marinas that I visit. No.. I am not talking about rake either.

Hunterowners.com specifications say the mast is about 34'6" tall so the mast itself must be at least 4 feet shorter due to deck plate height above the water. I can't measure the bend right now because the boat is tucked away for the Minnesota/Wisconsin winter, but using the 1% rule, it's bend is definitely too much as I think it would measure about six inches or greater.

Thanks again for your posts. they are much appreciated.

 

[Jake N Eggs]

The diagonals and reverse diagonals give the mast structural strength. Do not remove the reverse diagonals as you have mentioned.

 

[Crazy Dave Condon]

The rig is the same as on the 23.5. There has been alot of comments.

Without seeing a picture of the prebend of your mast, I am at a lost. The wire rigging or commonly called the standing rigging was made by Seco South for your boat. Generally, it is correct but with time the rigging does stretch. If that is the case, then you can take off the old rigging and send it off to a rigging loft with instructions to duplicate it but with a small shortening depending on what your needs are.

The way I use to set up the mast for tuning was to raise it without putting any prebend in it. With everthing loose, I would set the forestay at 1/3 to 1/2 of the studs in the turnbuckle, then adjust the backstay until there was prebend. Usually I would run a small line up the main halyard with a weight attached. When you have a distance of 4-6 inches between the line and the mast where the boom attaches, you are in the ball park for prebend of the mast.

The next was to tune the upper shrouds. Again using the same line or long measuring tape attached to the raised main halyard, I would check the top of the mast so it is in the middle not leaning to any side by adjusting the turnbuckles. I would tighten to a point that no more prebend is seen to what you have already. The next would be to tighten the lower shrouds to a point they are tight sometimes taking out some of the prebend. Experince told me that generally the lower shouds were tighter.

Adjustment to the uppers and lowers was necessary to a point where with the middle finger I could only pull on the upper 1-2 iches inward. Then I would tightrent the shrouds from the spreader to the lower part of the mast without any changing any prebend. Make sure that you understand when tightening these two cables, it goes opposite in direction. If you tghten on the starboard inner shroud, the mast could bend sideways to the port.

Then go sailing and see if you need to tighten or loosen. Major prebend will negatively affect the performance of the boat. If you want, send me a photo with the mast up to davecondon@mindspring.com and I will assist as it may not be clear from what I was talking about.

All time dealer for the most sold 240 sailboats world wide. American Marine & Sail Supply. I am retired but working alot harder these days rebuilding Boy Scout fleets.

Crazy Dave Condon

 

[Dan Johnson]

Scott...

Follow Crazy Dave's suggested tuning and you can't go wrong. He had hull #1 and I had hull #8 (still in use on the North East River each summer!).

 

[Dan Hill]

Mr. Condon is the main reason I own a 240 and I've never regretted a minute of it. He is the hunter water ballast guru.

 

[Scott2]

For all to see, here is a picture of the boat. Not the greatest, but all I could dig up.

 

[Don12364]

Thanks for the pic.
From what I can see (masthead not visible) the prebend looks a little large AND the rake also a little too much.
However, as the B & R rig relies on prebend I would tend to go on the basis of how the mainsail looked when hard on the wind (and reaching) - AND whether the boat was 'hard mouthed' when beating.
As a starting point the previously stated 1% prebend is a useful guide or 4" in your case (30' luff length).
Also 4-6" of rake is a good initial setting.

Now, if the turnbuckles are within a turn or two of coming apart then either something is amiss with the setup or the rigging lengths are wrong.
Presuming the mast is original and unmodified, then perhaps a tape measure on the wires in question (mast up) would enable comparison with the quoted lengths. Sadly I can no longer locate the table of Hunter standing rigging lengths but I would imagine Hunter Support or a rigging specialist could oblige.

And - This is the pic on the Luhrs web page under 'Our Fleet' 'Previous Models' (If pic is too large hit CTL & minus keys twice to see whole photo).
http://www.huntermarine.com/Models2011/HunterPreviousModels/240_1997-2005.pdf
From the look of the mainsail it could do with a bit more bend - if the mast could take it!

 

[Scott2]

Thanks for the web site with the H240 picture. The mast actually looks a lot like my sailboat so perhaps I am fretting over nothing. I can imagine that a raking can give the illusion of too much bend so I will look at that when I step the mast in the spring. I will also use the suggested trimming steps. Thanks everyone!

Warm Regards,
Scott