Spritsails for Dinghy Sailing
What is a Spritsail?
A Spritsail is a four sided sail usually laced on to the mast along its luff. It can range from almost square to having a pronounced peak. It may or may not have a boom, but it will always have a sprit. A sprit is a spar which supports the peak of the sail
Spritsail outperforms Bermudan Rigs??!!
Spritsail comparison conducted by Gifford Technology of Southampton. PDF file is largish, comes from bateaubois.com. Also compared was the Gaff sail, lateen and Bermuda rig. The Spritsail came up as best rig much to everyone's surprise (except me of course.) This is confirmed by another set of tests reported by Palmer in a 1990 Wooden Boat article on hull and rig efficiency. Go Spritsail!!
The Parts of a Spritsail
The four corners are called Peak at the top, Clew at the far end of th Boom, Tack at the bottom near the Mast and Throat at the top of the mast. The four sides are the Head, Leech, Foot, and Luff. The Sprit runs from the Peak and attaches to the mast. The tension on the Sprit is adjusted by the Snotter!
Not all spritsails have booms, some are loose footed. The term loose footed is also sometimes used for a sail that has a boom but is not laced, only attached at the mast and at the end of the boom.
Sprit Sails have a long history.
Its many qualities made it a favourite rig of working boats and sprit sails were a common sight in the 1700-1800
They are often represented in art of the period as in this "Duch Ferry Boat before a Breeze, by Simon de Vlieger
Their most well known use in England was on the Thames barges.
Square riggers had a type of spritsail placed bolow the bow sprit. It was a true square sail with sheets running from each of the corners. These ungainly spritsails were discontinued because of the difficulty in handling a sail that dangled so close to the water. The sailmaker needed to make drain holes to allow water out when the sail got caught in a wave.
Thames Barge has large loose footed Spritsail
Using the Windlass at the front the boat, the mast, which was set up in a tabernacle and could be bent back, could be lowered to pass under bridges, then quickly re-set.
Wikipedia has a good description of the Barges in their Spritsail article. The large spritsail is clearly visible with the sprit running diagonally from the mast to the far corner of the sail. Since it is loose footed the billowing spritsail can easily be tucked in when going through narrow channels and passing other boats.
Advantages of Spritsails for Dinghy Sailors
The Spritsail is a marvelously simple sail.
A spritsail allows a large area of sail to be set on a short mast. This means that the can be set on an unstayed mast. This by-passes all the difficulties and expenses associated with shrouds and stays.
This simplicity also translates in less hardware required (=less expense).
If the video has an error, click on the youtube logo, it will take you to youtube and you can watch it. This happens on some browsers.
Because the mast is short it is easier to put up and often is made to fit inside the boat. The sprit is usually about the same length as the mast and also fits neatly in the boat.
The spritsail is usually laced on the mast. There is no halyard and very little to fuss with, once the sail is set.
There is one sheet to tend, either from the boom, or from the clew corner of the sail if there is no boom.
Because the center of effort is low there is less tendency for the boat to heel in high wind.
It is well behaved and simple to use.
It is easy to put away. The sprit is removed and the sail can be rolled around the mast. Often the whole mast is lifted and stored inside the boat with the sail still on. It makes riggin the boat quick when ready to go sailing the next time.
Here is my Skerry in a test drive of the jib I'm experimenting with. The jib improves the airflow around the spritsail quite alot. It complicates the lines and I'm now experimenting with a self tending sprit that's a bit smaller.
The spritsail was a favourite in working boats because the lack of a boom allowed for a clear deck with easy access to the hold.
The loose footed spritsail also allowed boats to pass through narrow channels by taking in the sail at the bottom.
The sprit sail compares favourably with more modern rigs in all points of sail except when pointing upwind. It matches speed while going downwind.
There are some disadvantages to the Spritsail
It is not simple to reef while underway. There are many ways of reducing sail. Scandalizing the sail (removing the sprit altogether or repositioning it to a lower position) and folding down the peak towards the tack effectively reduces sail area. It is also possible to brail in the sail by running a line on the far edge and pulling in the sail.
I run a line from the end of the boom to the top of the mast and cleated down near the adjustment line for the sprit. If I want to fold up the sail, its easy to just pull on the line and the boom folds up to the mast. Its best to loosen the sprit. This allows me to get the boom out of the way if I want to row for a short while, or get the sail out of the way.
Another disadvantage is that if the spritsail is not set properly or if the sail is not cut well the sail peak can twist.
There is a good tack and a bad tack. On one tack the sprit interferes with the airflow. This is much less than expected on my boat, and on certain headings the so called bad tack is better than the good side. I don't understand why but it happens.
Like the other square sails such as the lug sails, it does not point upwind as well as the high ratio triangular marconi rig. Adding a jib to the sprit sail rig improves the sail when heading upwind.
The boom can lift in a gust of wind. I've grown used to how it feels and can control it but when it first happens it is a surprise. I've experimented with running a line from the middle of the boom to the mast to act as a cunningham to control the lift. It works but its just a nuisance so I just learn how to deal with it with my sheet.
Lovely video of a Pin Mill Barge.
Barge Cambria being sailed and narrated by Bob Roberts. At 25:44 he sculls his tender to shore to go to his daughter's wedding, complete with morris dancers. Before that there are images of the barge being sailed. A documentary of a way of life that is gone.[HOME]
I try to be accurate and check my information, but mistakes happen.email me if you find mistakes, I'll fix them and we'll all benefit: Christine