Skerry mast

The stock Skerry sail is 58 Sq ft. Can I put a larger sail and still not compromise the boat's strength. My mast/boom are bigger and stronger than specified but the step/partner has not been modified.

What I would like to do is is put a larger sail that has a couple of reef points. When there is not much wind I use the larger area and use the reefed sail when there is more wind. I'm thinking about 70 sq.ft. I have drawn such a sail and the balance seems ok, now I need to figure out the strength.

thanks, this forum is so helpful.


14 replies:

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RE: Skerry mast


You should be fine as long as the balance and attachment points are taken care of and you really do reef at the right times.

The bending moment on your mast is a product of the windspeed, the sail area and the vertical location of the center of effort. As you reef, the last 2 come down. So if your reefing keeps up with the windspeed increase, you can guarantee that the bending moment on the mast (and the resultant forces transmitted to the step and partner) stay constant and never exceed the forces generated by the original sail.

Love your herd, BTW. We once had a pair of feral kittens that trained up to be the most people-happy cats you've ever seen, and they kept their mousing skills.



RE: Skerry mast


My Jimmy Skiff sail is 70 sq. ft. as compared to the stock sail of 60 sq. ft.  I built my sail from a custom kit by Sailright.  It has one row of reef points.  As you mentioned, and Laszlo confirmed, early reefing is key.  These boats are so light that the increased sail size really does not seem to over-stress the rigging, but will result in a knock-down if you don't reef, or at least let the mainsheet go quickly when a sudden gust comes along.

It is best to reef before leaving the shore if you expect a fresh breeze.  However, it is also a good idea to practice on-the-water reefing for when the wind picks up while you are too far from a 'safe harbour'. 

Reefed JS


RE: Skerry mast

Do you and other Skerry owners feel it's under-powered with the 56 sq.ft. sail plan?  I'm about to build a Skerry and with its ultra light weight, and no deck, rail, or hiking straps to facilitate hiking out, it seems to me that it could get very tender with a lot of sail when the wind picks up, and be not so easy to reef while under sail if you find the conditions have strengthened.  You'd pretty much have to heave to (if you can do that with a Skerry) and reef while luffing the sail.  Will the boat balance OK in wind when you're sitting on the rail?

I've sailed and raced "light weight" boats like JY15s, Lasers, and Hobie's and they're all designed for hiking, even with a trapeze, so you can use your body as a counterweight against the force of the wind.

 Every single pic I've devoured of the Skerry (I think it's just eye candy) always shows the crew inboard, fairly close to centerline.  The Skerry doesn't look like a design that lends itself for hiking to counter sudden wind force on a large sail.  Sustained winds are one thing, but those sudden puffs are what will getcha!

Also, did John design this boat to be most efficient sailed level or healed over?  John?  Dinghies that are designed to be efficient healed over have hulls, daggerboards and rudders that generate lift when healed.  It looks to me like the Skerry may be most efficient (fast) sailed level, like a JY15, Laser, or Sunfish.  I'd be interested to hear John's thoughts.

RE: Skerry mast

-<Do you and other Skerry owners feel it's under-powered with the 56 sq.ft. sail plan?> 

Although the sail is only 56 sq feet, the moves like the wind if there is any wind to be had. It is so light that it accelerates very quickly. So... most of the time I did not want any more sail to deal with. Particularly since I was a bit of a total beginner and a somewhat smaller sail plan is a good way to learn. 

I am currently planning a larger sail for 2 reasons. I want to try it, I am simply curious. And sometimes when conditions are just right, I would like to go faster. This is just the thrill seaker in me speaking. I know it is a bit  illogical to choose a boat that is dry, not tippy, and quite easy to sail, and try to complicate things, make it more likely to tip and take in water!

I am certain that the boat will not like to be reefed while underway unless it can be done from behind the seat where I sail. Moving weight around has alot of effect on how the boat behaves and at least when I tried, going to the front to mess with the sail when it is windy, changes the way the boat points into the wind and makes it turn sideways.  (weather helm I think it is called.)

I think that with a Chinese Junk sail you might be able to reef while underway and not have to go forward. The weight of the battens I think. I'd like to try a chinese rig.

The Skerry is designed to be sailed pretty much straight up, not heeled. It doesn't heel alot anyway. Even in very strong wind I have never dared sit on the rail. Maybe others have? I just move my weight around to the side and sort  of push up against the side I if I need to. Even sudden gusts have not really made me heel. I tend to depower the sails by letting out my line if a really big gust comes. I'm a bit timid and would prefer to slow down rather than try to weather the big gusts.

I can't imagine hiking out, the way the hull is made doesn't make it easy and sitting on the side would probably tip you over anyway.

That's my experience and thoughts. Others...?











RE: Skerry mast

From the CLC Skerry page...

An option that is gaining in popularity is a larger gunter-sloop rig. The rig is that of the well-tested Passagemaker dinghy, comprising a 58 square foot mainsail and a 19 square foot jib. This will be a fast and weatherly option and is intended for sailors for whom speed is of paramount importance. The mast is aluminum, supported by three stainless steel shrouds, while the boom and yard are wooden. The sloop rig can be added at any time or retrofitted to an existing Skerry.

skerry with sloop rig


RE: Skerry mast

Hi Ron

I looked at the alternative rig for the Skerry. It seems a bit complicated for my taste. I'm not sure I like having stays for one thing. Since I mostly solo having a little jib is not that attractive.

I think one of the great qualities of the Skerry is its simplicity and adding another sail reduces that advantage. 

I would love to hear from people who have actually put this rig on their Skerries and sailed it.

I think a balanced lug a bit lower than the current rig to allow for more area would be a good way of adding more sail without much complexity.  It needs to be raised with a halyard but once its up not much more difficult to tend. One advantage is that it is possible to reduce sail while underway. Easier than with the Sprit or the Gunther rig.


RE: Skerry mast

>>>>>>>always shows the crew inboard, fairly close to centerline.  The Skerry doesn't look like a design that lends itself for hiking to counter sudden wind force on a large sail.  Sustained winds are one thing, but those sudden puffs are what will getcha!

Also, did John design this boat to be most efficient sailed level or healed over?  John? >>>>>>>

Well, a coupla thoughts:  First, the Skerry's hull shape is unusual, at least these days.  It's strongly flared and gains stability very quickly as it's heeled.  Even in very strong winds the Skerry sails nearly upright.  Second, the interior was fairly deliberately designed to encourage sitting low in the boat, where the sailor's weight does the most good for stability without the need for a lot of exertion.  As a cruising daysailer, this is desirable.

The great majority of 15-foot sailboats these days are racing dinghies.  Even 15-footers meant to be casual daysailers conciously mimic racing dinghy styling and architecture.  You tend to sit ON these boats rather than in them.  It's not comfortable, and the seats and fittings are so heavy that none of these boats is cartoppable like the Skerry.

As to adding sail area:  everyone who has actually spent some time sailing a Skerry agrees that the stock version has plenty.  I haven't sailed one of the many Skerries rigged as a sloop, but I imagine it's a turbocharged ride.  

I know of some Skerries rigged as luggers, and that'd be my preference for a little more power in a cruiser.  They're easy to reef.  We've shipped some Passagemaker Dinghies with a lug rig.  I pasted that rig onto the Skerry in CAD and it looks good, although the mast must be moved aft at least six inches--that would complicate the interior.  With the stock sprit rig tested and established as ideal, I've no plans to make the lug a kit option.

Lug this.

RE: Skerry mast

John -

Thanks for taking the time to reply.  The whole idea of being able to sit IN the boat and basically have the interior available to stretch out is one of the reasons I'm going to build the Skerry instead of the Melonseed.  At 6'1" and a long-waisted 218lbs.,  I'm looking forward to the room.  I'll be building it as spec'd.  I'm not going to miss the constant sit in, sit out, sit in, hike out, sit on, lean out routine of my JY15.  I sold it because I was planning to build my own boat...which will be the Skerry.  Also really like the tiller arrangement.  Hopefully by the time the boat is in the water next season, I'll have lost that 20lbs, which will certainly make the boat sail faster. 


RE: Skerry mast


     Sailrite has a Swampscott Dory sail plan (sprit) at 73sq. feet and a jib to go with it for an additional 11.7 sq. feet bringing the total to almost 85 sq. feet. The mast needed doesn't appear to be that much different from Skerry's and you might just be able to use the original. I would rake the mast as advised to offset the pull of the jib. This plan is the plan for a 16' modified Swampscott from Gardner's "Building Classic Small Craft" and is what I am considering for the Skerry I am about to build. I don't think this would be too excessive and I like the looks of a sprit with a small jib. Hope you find that combination you're looking for. There are also plans for a simple 61' sprit  and a 68' sprit for a Duck Trap Wherry that would both fit the original Skerry mast and sprit boom. Have fun!


RE: Skerry mast

Jim, My brother has a Melonseed that he bought rather then build.  I finished my Passagemaker and we both when out in our boats one day.  I sailed faster - was very pleased with the Passagemaker's performance.


RE: Skerry mast

David -

That's interesting to hear the Passagemaker was faster than the Melonseed.  Are you using a sprit rig or lug rig on the Passagemaker?  

RE: Skerry mast

   I am using the Gunter rig. The aluminum mast comes in two sections. One long and one short. My inclination is to put the shorter on top with the masthead epoxied in as directed. Is there any reason to reverse the order?


RE: Skerry mast


John wrote this: "I would put the short piece of mast towards the top. At an

engineering level I don't think it makes any difference. But since
the location of the joint influences the bend of the mast under
sailing loads, and the shape of the bend is a tiny bit more ideal for
the sail shape if the joint is up high, I'd put the short piece on

John C. Harris



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