converting fractional rig to masthead?

[cygnus20]

Hi - I bought a light displacement Hinterhoeller Cygnus 20. The guy who sold it to me had built a wood mast but the boat was designed for an aluminum mast. Got a good deal on an International 14 aluminum spar. My boat displaces 600 lbs so not heavy. Can anyone suggest the best way to convert the fractional rig Proctor mast to a masthead rig. The main is no problem since the track goes to the top of the mast. But the jib is masthead and the spar is rigged for a fractional foresail. Can I just put a block at the top of the mast or should I move the stays further up the mast along with the spreaders? Thanks for any thought you may have!

 

[VT Fitz]

Risking design of your boat

Your first issue will be the forestay, which needs to reach the masthead before you can run a jib up there. You will need a secure attachment point for that. You don't want that to give way in heavy weather, leading to a catastrophic failure.

More fundamentally, I think you want to question your motive here. Are you trying to improve the boat's performance or avoid the expense of a new jib? If the motive is the latter, then you are probably compromising the former. If you use an overpowered jib, you'll throw the boat's design out of whack by moving the center-of-effort too far forward, and she won't sail very well. You may also stress the rig beyond it's design tolerance, again, risking a catastrophic failure.

My 2¢.

 

[larryw]

Ameteur mods almost never work out.

 

[RichH]

Changing to a masthead rig from a fractional ..... is going to give you problems: The 'balance' between the foresail and the mainsail is going to 'way off'.

The simple answer is this change will not work well! ....unless you also change the underwater shape and undewater area of the hull - moving the centerboard, etc. 'more forward' to compensate; OR, you will have to move the location of the mast - further aft on the boat. Without such 'compensations' the boat will have difficulty in sailing 'upwind' and may have severe 'helm balance problems'.

If you are looking for better 'downwind' (lower than a close or broad reach) sailing ability .... then you can apply an asymmetrical spinnaker, "code-0", etc. run to the masthead; such a sail requires NO forestay. For ultra-light winds you can also fly a 'drifter' (very LARGE headsail made of VERY light sail fabric) that has a wire or high tech 'rope' sewn into its luff (instead of using a 'forestay') .... and you remove and stow the sail (and its 'stay') when not using; a drifter can be attached to the masthead (via halyard, etc.).

Simple speak: leave the sail plan alone (keeps the Center of Effort and the Center of Lateral Resistance in 'balance') and get a spinnaker, code-O, or even a 'drifter (all run to the top of the mast) for 'downwind' sailing.

 

[OldCat]

Hi - I bought a light displacement Hinterhoeller Cygnus 20. The guy who sold it to me had built a wood mast but the boat was designed for an aluminum mast. Got a good deal on an International 14 aluminum spar. My boat displaces 600 lbs so not heavy. Can anyone suggest the best way to convert the fractional rig Proctor mast to a masthead rig. The main is no problem since the track goes to the top of the mast. But the jib is masthead and the spar is rigged for a fractional foresail. Can I just put a block at the top of the mast or should I move the stays further up the mast along with the spreaders? Thanks for any thought you may have!

I am not sure what you are trying to accomplish. According to this link, your boat appears to have been designed with a fractional rig in mind (http://www.pbase.com/nonsuch/hinterhoeller_cygnus_20). Why not just go to a fractional? As others have noted, a change is unlikely to produce a balanced boat.

OC

 

[Joe]

Hi - I bought a light displacement Hinterhoeller Cygnus 20. The guy who sold it to me had built a wood mast but the boat was designed for an aluminum mast. Got a good deal on an International 14 aluminum spar. My boat displaces 600 lbs so not heavy. Can anyone suggest the best way to convert the fractional rig Proctor mast to a masthead rig. The main is no problem since the track goes to the top of the mast. But the jib is masthead and the spar is rigged for a fractional foresail. Can I just put a block at the top of the mast or should I move the stays further up the mast along with the spreaders? Thanks for any thought you may have!

Why don't you just cut the jib down to fit the boat, rather than modifying the boat to fit a sail that will wear out eventrually.

 

[COOL]

On the other hand, if you have the boat,
you have the mast, and you have what
ever sails you have, you might as well
throw them together and see what results.
It is only a 20' day sailer with no resale value
so there is not much that can go wrong.
Depending on the vintage of I 14 the rig
comes from, it may handle the side loading
of a masthead headsail with out modification
as it would have been designed for double trapping
with a masthead asymmetric at a 90 deg AWA.
You may need to lengthen the uppers and raise the
hounds, as well as attaching a new headstay.
But it can't hurt to give it a go.
It is a small boat with small loads,
at the worst you might bruise an ego.

 

[VT Fitz]

Catastrophic failure

With all due respect to the prior post, a broken spar can bruise quite a bit more than an ego. Never mind the inconvenience of potentially being stranded in a big blow with no rig and the canvas dragging the boat down into the briny deep, a direct blow from a broken mast is potentially fatal. It's that kind of reckless reasoning that leads to incidents you read about in the paper and just shake your head about.

My 2 cents.

 

[PaulK]

Worth more than $.02

With all due respect to the prior post, a broken spar can bruise quite a bit more than an ego. Never mind the inconvenience of potentially being stranded in a big blow with no rig and the canvas dragging the boat down into the briny deep, a direct blow from a broken mast is potentially fatal. It's that kind of reckless reasoning that leads to incidents you read about in the paper and just shake your head about.

My 2 cents.

I keep thinking about borrowing the spinnaker from a Frers 41 and rigging a block at my masthead to hoist it with. The image of the top 12 feet of my fractionally rigged masthead turning into a pretzle in a puff that takes us to 15 knots keeps me from doing it.

 

[RobertLangdirect]

Read the PHRF post. The P-31 is a 7/8 rig. Frequently, even that gets overpowered.

 

[Ross]

This discussion demonstrates why naval architechs get paid for their work. You CAN do anything to a boat but anything that you do will have an effect on almost every aspect of the boat.
Just the change from aluminum to wood for the mast changed the center of mass and raised it some. Going from fractional to mast head changes some of the sail shaping options that come with a fractional rig.

 

[cygnus20]

original sail plan was masthead

Thank you for the interesting responses! I had the impression I would get an email saying there had been answers to my post but google found them from a random search. The boat was designed by Hinterhoeller as a masthead rig. The spar I bought is set up as a fractional rig. The centre of effort is therefore not changed. I like the idea of putting a masthead stay and block on the Proctor mast and seeing what happens. On the other hand it would be no big deal to put a stainless ring at the top of the mast for all the stays and sliding the spreaders up a bit. Very interested in your take on this! Tom

On the other hand, if you have the boat,
you have the mast, and you have what
ever sails you have, you might as well
throw them together and see what results.
It is only a 20' day sailer with no resale value
so there is not much that can go wrong.
Depending on the vintage of I 14 the rig
comes from, it may handle the side loading
of a masthead headsail with out modification
as it would have been designed for double trapping
with a masthead asymmetric at a 90 deg AWA.
You may need to lengthen the uppers and raise the
hounds, as well as attaching a new headstay.
But it can't hurt to give it a go.
It is a small boat with small loads,
at the worst you might bruise an ego.

 

[Ross]

Re: original sail plan was masthead

If the boat was built as a masthead rig and later was refitted as a fractional rig then the center of effort changed but the center of lateral resistance remained the same.

 

[cygnus20]

Thanks. The boat was never fractionally rigged. I bought the fractionally rigged I 14 Proctor mast and plan to adapt it it to the boat. At present it has a wood mast which was built by the former owner. The boat was designed to have an aluminum mast. Since it displaces only 600 lbs I'm guessing the mast can handle the load. I have more experience with heavier displacement keel boats so this is a new experience.

 

[cygnus20]

apologies - should have read converting fractionally rigged proctor mast I bought to a masthead rigged boat - the boat was designed and originally built with a masthead rigged aluminum spar - the mast went missing so the guy who owned it before me built a wood one which affected the centre of effort and made the boat less stiff - I found a fractionally rigged I 14 proctor mast which I want to adapt to the boat - a 20ft open cockpit, 7ft beam daysailer - it only displaces 600lbs - thinking of putting a stainless ring at the masthead and running the stays from there and sliding the spreaders up the mast to match - many thanks for any insights you may have!