Sunday, May 25, 2014

Different Rigs on the Same Boat

Most of my published sailing boat plans come complete with a number of different rig options.What makes mine different from most other offerings on the market is that I try to arrange the various rigs so that the original mast can be used for several different rigs, and that the original mast steps and mast partners can be used. By that I mean that a builder can choose one rig at the time of building, and at a later date, rig the boat differently by simply ordering some new sails and, maybe, making a few different yards, or gaffs etc. But no structural changes need to be made to the boat herself, and the rigs can be changed at will.

Each photo below is of Paul Hernes' Phoenix III named Willy Wagtail.  Even though she is sporting a green sheer strake in the first, second and fourth photos, and is looking nicer with a more plain colour scheme in the other two, she is the same boat, and nothing has been changed other than the sailing rig.

Phoenix III with her sprit rig set without a boom. This can only be done on boats which have had the correct sheeting geometry designed-in from the beginning.

Here is the very same boat, but with a boom fitted. The boom makes the boat slightly easier to handle, and allows more options for sheet locations, but the boomless rig is more seaworthy, as there is no boom to drag in the water if the boat is over-pressed - a situation which often prevents the helmsman from being able to ease the mainsail and can lead to any boat sailing herself over into a capsise 

Showing off with her new paint job, Willy Wagtail has been rigged with the balance lug sail. The mast is the original, the mast step is original, and the mast partner is original. All Paul did was use a different sail. Some days, he starts off using the larger sprit rig (which can be sailed with or without the jib) and changes to the smaller balance lugsail if the wind comes up, or if he starts to feel lazy.

This shows the boat sailing under mainsail alone

In this photo, Willy Wagtail is carrying the flying jib from the sprit rig, and a standing lugsail taken from a Joel White-designed Poohduck Skiff - which by coincidence is a design which can also be sailed with or without her jib.

The matter of hull/sail balance is frequently brought up, and one can't just put any rig on any boat and expect the boat to perform properly. The rigs have to be proportioned in such a way the hull balance is maintained within certain limits, otherwise you will end up with excess weather-helm or, even worse, lee-helm. At the design stage I put a lot of time into proportioning the various sail plans so that they will balance. However, you can see from the last photo above that there is a lot more tolerance for centre-of-area and centre-of-lateral resistance changes than the theorists will admit (I limit my comments here to small centreboard and leeboard dinghies - and even then, the rudder and centreboard proportions, area, and location must be taken into consideration when following this line of thought).

This is Periwinkle with her Periauger or Cat-Ketch rig as designed...

...and here she is with the mizzen removed altogether, and the main mast moved back to a third mast partner and step. This step was designed-in to allow just this procedure.

Another shot of Periwinkle moving well with the mast and mainsail in the third location. This arrangement changes the sail area from 155 sq.ft to 104 sq.ft without the need to reef both the mizzen and the main.

Here, the crew of Periwinkle were anticipating tricky conditions outside the cove and had not only used the mainsail and mast in the third location, but had tied in a reef as well.

In this photo, owner John Shrapnel has moved the main mast to the third location, and has set the mizzen sail only. In this configuration, the boat is only carrying 52 sq.ft of sail, but she is under good control and is moving fast. John mentioned eight knots by GPS with the boat very lightly loaded - but anyway, she is going well.
This is another shot from the same day (52 sq.ft mizzen sail only) and I am told by a person who I trust (no names) that Periwinkle was actually overtaking the boat in the background.
Another Periwinkle but this one has been rigged with the gaff-headed cat rig (details supplied with the plans in addition to the cat-ketch rig). The mast is exactly the same as the main mast on the cat-ketch rig, and is stepped in the standard forward location. This rig can also set a small jib not shown here.
John Shrapnel is the most experienced Periwinkle owner at the moment, and he has tried a number of different rigs, and configurations, and is currently using the standard balance lug mainsail (the one from the standard cat-ketch rig), but with the mast set in the forward location (normally balanced by a mizzen mast and sail). One would think that this arrangement would induce lee-helm - something to be avoided at all costs. However, John has pulled the forward end of the boom aft to the mast, therefore moving the centre-of-area of the sail aft enough to prevent lee-helm, and in the process the aft end of the boom has cocked up high above any vulnerable heads. The result is that the rig is now a 104 sq.ft Standing Lug.

See in this youtube clip just how well the boat goes when being sailed by a light crew - in this case one person.

The old-fashioned rigs have got a tremendous amount going for them if you know what you are doing, and if you are prepared to be patient with your development. All basically cordage, wood, leather, and cloth.

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