Converting Fractional Rig to Masthead

[The Fox]

I have a Fractional Rigged Cole 43. I would like to convert her from Fractional Rig To Masthead for 2 reasons. 1. Having to continually adjust running backstays is a pain and
2. Because of the huge main and the much smaller headsail, with full main and full headsail the boat is not balanced, and requires a lot of lee helm which becomes quite tiring.
By increasing the size of the headsail I figure I can move the centre of effort forward and relieve the excessive lee helm. By removing the running backstays, I can I can reduce the amount of trimming and the wear on the main etc.
The question I have is: Will this affect the structural integrity of the mast? and, if so, how can I correct it?

 

[whatfiero]

Cole 43

Sailboat data .com lists your boat as a mast head sloop has it been converted down worth a trip up the stick to check out If ya have front halyard shives and a cable attachment point then should be an easy conversion back Is it a B& R rig?

 

[mitiempo]

According to SailboatData http://sailboatdata.com/viewrecord.asp?class_id=6398
the Cole 43 is a masthead rig. Probably best to communicate with the builder or ideallyt designer if possible. Failing that another designer. Keep in mind that a fractional rig often has a mast that is more flexible than a masthead rigged boat. You may need a new mast if that is so in your case. I wouldn't undertake this without the advice of an experienced architect.

Pretty boat, looks like it could have come from the S&S drafting board.

 

[harv]

I’ll take an amateur crack at this.
The boat was built in Australia, in the 1970’s, and I would assume that it was built as an offshore racer-cruiser. AU has heavier winds and so the normal sail plan was probably a main and a 110 jib. The genoa jib was intended as a low wind sail.
Masthead or fractional may not matter much.
The heavier winds and tall mast, and1970 mast technology made running backstays necessary.
When you put the genny up in normal winds it moved the combined center of effort forward of the center of lateral resistance (the balance point) and produced the lee helm. You won’t notice it in low winds.
Short of replacing the mast, as Metimpos suggested, you might try to lead the backstay release and setup mechanism back toward the wheel area where you and a mate can get at it easily. And a auto helm would help. A jib boom would also cut down the sail handling.
It looks like a sweet boat, enjoy it.

 

[mitiempo]

I’ll take an amateur crack at this.
The boat was built in Australia, in the 1970’s, and I would assume that it was built as an offshore racer-cruiser. AU has heavier winds and so the normal sail plan was probably a main and a 110 jib. The genoa jib was intended as a low wind sail.
Masthead or fractional may not matter much.
The heavier winds and tall mast, and1970 mast technology made running backstays necessary.
When you put the genny up in normal winds it moved the combined center of effort forward of the center of lateral resistance (the balance point) and produced the lee helm. You won’t notice it in low winds.
Short of replacing the mast, as Metimpos suggested, you might try to lead the backstay release and setup mechanism back toward the wheel area where you and a mate can get at it easily. And a auto helm would help. A jib boom would also cut down the sail handling.
It looks like a sweet boat, enjoy it.

Mast technology existed before the 70's to allow a masthead rig without runners. Fractional rigs have been around for a very long time. Fractional rigs have many advantages. They are main driven as opposed to a masthead rig that was jib driven - especially under the IOR which came into effect in January 1970. Being main driven the number of jibs needed was minimal, many performance cruisers with fractional rigs only need one jib unless storm jibs were used, while a masthead rigged boat often carried 5 or 6 to suit different conditions. The smaller jibs on a fractional rig are easier to tack than the larger jibs and genoas of a masthead rig and are often self tending, especially on performance cruisers. The fractional rig with its bendy mast allowed flattening of the main through mast bend to suit the conditions, something the much heavier section mast of a masthead rig doesn't allow. A well designed fractional rig doesn't need, nor can it really use, a genoa as it doesn't have a a forestay going to the masthead. Spinnakers are easier to handle as they also are not set from the masthead. Most fractional rigs are easily sailed under main alone as it is the driving force. Not all fractional rigs have or need running backstays, which leads me to believe you have a smaller mast section than some and/or is a 3/4 or 4/5 fractional as opposed to a 7/8 or 9/10 which most often doesn't need running backstays. Many racing boats with running backstays either did not have a permanent backstay or it was very lightweight and used for controlling mast bend and these boats needed the runners for rig support, sometimes called checkstays. Performance cruisers most often have a permanent backstay and their running backs are not needed until the wind gets up to 25 knots or so to eliminate mast pumping. Many feel the fractional rig is easier to handle due to smaller loads on the jib sheets and easier tacking, and offer better performance than a masthead rig. Coming into a harbor or anchorage the jib is dropped and the boat becomes very easy to handle under main alone and is also more responsive than a masthead rig under main alone.

 

[Benny17441]

Concur with "mitiempo", that is not a DIY project. Check with a marine architect. It seems the rigging may have been previously modified and perhaps the cause of the problems you have been experiencing. Get a hold of the original specs and verify what spar do you currently have. This might be a rather costly endeavor.

 

[cas206]

move the centre of effort forward and relieve the excessive lee helm.

Is that statement correct? Here is my reasoning on why it's not. If it is correct, which one of the following is in error?

Weather Helm means the boat wants to rotate upwind and stall.
Lee Helm would imply the opposite.

Weather Helm means the point of force on the sails due to wind is aft of the center of rotation of the hull. Lee Helm means the point of force on the sails due to wind is forward.

So wouldn't putting more sail forward, move the force point of the sails more forward, which implies more lee helm, not less?

 

[Scott T-Bird]

I'm guessing from Fox's phrasing "requires a lot of lee helm" that he means the boat has weather helm which requires steering to lee. Still, a balancing issue should be resolved with the right sail plan, I would think.

Regardless, wouldn't a boat that is built for a fractional rig have a mast step that is forward of a boat that is made for masthead rig? I would also guess that the mast might be too bendy for a masthead rig. Many fractional-rig masts taper significantly above the hound for the forestay. But I am confused as to why a boat that is designed as masthead rig, as indicated by sailboatdata, would be set up as fractional. Perhaps it was somebody's bad idea in the past ...

I wouldn't make a change without consulting a designer for a comprehensive list of issues, that's for sure.

 

[mitiempo]

Is that statement correct? Here is my reasoning on why it's not. If it is correct, which one of the following is in error?

Weather Helm means the boat wants to rotate upwind and stall.
Lee Helm would imply the opposite.

Weather Helm means the point of force on the sails due to wind is aft of the center of rotation of the hull. Lee Helm means the point of force on the sails due to wind is forward.

So wouldn't putting more sail forward, move the force point of the sails more forward, which implies more lee helm, not less?

No, that statement, as written, is incorrect. I missed that. But as posted by Scott the op may mean something a bit different.

More sail area forward will cause or increase lee helm. Not a good thing to have.

More sail aft will increase weather helm. You want weather helm but not an excessive amount.

It could be somebody's bad idea or it could have been done by the builder/designer or another designer. The boat may have lost the original mast racing and been switched to fractional when it was replaced. It will be expensive to change back, probably 5 figures or more - and hiring a qualified naval architect is really the only way to do it properly. A new mast will be required if the section is too small.

 

[The Fox]

Reply to All

Gentlemen(and Ladies)
I thank you very much for your very informative reply's to my original post.
I do apologise for the incorrect statement on the' Lee helm'. You are right, the boat does tend to want to round up into the wind because the centre of effort is too far aft and therefore requires quite a lot of lee helm to correct it. I understand that this is termed "weather helm".
With regards to the mast, the boat has done quite a lot of racing in its early years(It was built in 1984 and quite an impressive performer in its day) so may have been refitted with the 3/4 fractional rig (Although I have not seen any evidence in the records of a refit).
The mast is 'keel stepped' so is impossible to have it moved forward(or even 'canted forward' for that matter). Also the mast is designed as a fractional rig as it tapers torward the head and has a slight rake aft toward the top.
Somehow I have to get the centre of effort forward to correct the weather helm. Even a bigger headsail does not seem to help.

 

[whatfiero]

Converting

Well ya can shorten your boom and cut down your main sail. Try reeling the main in 1' incraments test sail do the math to figure how much sq in needs removed to balance the rig and cut should'nt need a arcatect to reduce head sail

 

[Scott T-Bird]

How do you make a masthead rig into fractional?

It seems to me that a boat designed for fractional rig would have the mast stepped further forward so that a bigger mainsail is balanced properly with a smaller head sail. So somebody simply exchanged the mast but left it in the same place? No wonder it is difficult to balance. Sure, a larger head sail might make a small difference. So was the boom matched with the mast for a large mainsail? No wonder the COE is too far back.

Why should you need an architect to change back? Theoretically, why not just find the original mast (and boom) and purchase a new one (or a used one if a good one can be found). Sure, that's expensive, but it seems like the right thing to do under the circumstance.

 

[mitiempo]

Well ya can shorten your boom and cut down your main sail. Try reeling the main in 1' incraments test sail do the math to figure how much sq in needs removed to balance the rig and cut should'nt need a arcatect to reduce head sail

Problem with that solution is that with a 3/4 fractional he will still need the running backstays.

 

[mitiempo]

A larger headsail will not make much difference if set on the existing forestay, any added area will be aft of the mast.

 

[mitiempo]

I would still suggest a qualified naval architect. As I and others have posted it will be expensive to change. The current rig may be the result of someone not qualified. Why spend 10k or more and still have it wrong?

 

[Scott T-Bird]

Well, I guess because it wouldn't be wrong if it was done the same way as it was originally. I would find a sister ship that never changed its rigging and copy it.

 

[mitiempo]

Well, I guess because it wouldn't be wrong if it was done the same way as it was originally. I would find a sister ship that never changed its rigging and copy it.

That makes sense, but comes at the top of the expense range, requiring an entire new rig.

It would be interesting to see a NA experienced with rigging design and have him analyze the current rig for an opinion.

 

[The Fox]

That makes sense, but comes at the top of the expense range, requiring an entire new rig.

It would be interesting to see a NA experienced with rigging design and have him analyze the current rig for an opinion.

Whatfiero may have something here . I have found that if I reef the main down to the first reef(Slab Reefing) the weather helm is reduced quite considerably and the boat is much better balanced. Only problem is that the big main produces great thrust in light winds.

 

[rufus1138]

hmmm.....an excuse for a bowsprit and masthead forestay? it would balance against the backstay and add effort forward in the plan while adding sail area and making the boat balance, effectively a cutter now with all of those benifits. starting to sound like an old school herschoff americas cup boat?

 

[HEINZIR]

Not so Fast

Be aware that you may end up with unintended consequences if you just move the forestay up to the masthead without any other rigging changes. On most fractional rigs, the upper shrouds only go as high as the forestay, they do not go to the masthead. The section of the mast above the original forestay attachment has no side support. A genoa or spinnaker flown from the masthead could put loads on the top section of the mast that it was not designed for.

I found this out the hard way on my 23' Venture of Newport cutter. Both the inner and outer forestays originally terminated within a foot of each other on the mast. She was what you might call a "fractional rigged cutter." The previous owner changed this, moving the outer forestay to the top of the mast. Being none the wiser, I liked the idea and kept it that way.
The masthead rig had several advantages: it opened up the slot between the jib and staysail, preventing the jib from backwinding the staysail. It made tacking easier. It allowed me to fly the jib up higher in light air. It allowed me to use bigger sails.

In time I acquired light air drifter with a masthead size luff and an asymmetrical cruising spinnaker. I was day sailing in light air on Lake Superior when I was surprised by a line squall that came up from behind. I had the spinnaker up at the time. The force of the wind knocked Chiquita over so far that my little 5 lb Hi Tensile Danforth stern anchor tipped out of its bracket on the transom and went in the water. The boat anchored itself by the stern! The squall lasted only a few minutes during which I was able to pull the sock down over the spinnaker. I didn't notice any damage and returned to the dock, much humbled. The next day, with some friends as crew, we departed Duluth Harbor for a 90 mile cruise to the Apostle Islands. The mast was perfectly straight when we left, on starboard tack. When we switched to port tack the top would bend about 2' to the side. The mast was "sprung."


My insurance company agreed to pay for a new mast so I ordered a new blank extrusion. I wanted to keep the masthead rig so I did a lot of research and looked at a lot of boats with cutter rigs. This was before the internet so I spent a lot of time at the library. I even wrote to Ted Brewer and asked his advice. I included a number of sketches of possible alterations, including one with jumper struts and one with double spreaders. Mr. Brewer was kind enough to reply and indicated that the best solution to keeping the outer-forestay-to-the-masthead rig would be to move the upper shrouds to the masthead as well, move the spreaders and lower shrouds up to the middle of the mast, and add running backstays to oppose the pull of the now unsupported inner forestay. That is exactly what I did. This is how many cutters are rigged and it has been working well for me for about 30 years now!

The running backstays are not used in normal sailing, only in heavy air or when flying the drifter or the spinnaker. I have snap shackles at the bottom of their tackles and clip them to the original chain plates when not needed. There they serve as intermediate stays. I can also clip them to pad eyes on the cabin top to serve as "baby stays" to keep the mast aligned when raising or lowering it. Chiquita is, after all, a trailerable boat. I have discovered one other benefit of the runners that is becoming more important as I get older: they provide a very strong, safe, and perfectly positioned hand grip for stepping up from the cockpit to the deck or cabin top.