Deciding on a Rig

by Adrian Granchelli

The question: “What kind of rig will our Transat boat be using” came up really early in this project.  The more traditional design, used by the previous year’s Sailbot, became the first option.  However, this new challenge (transatlantic crossing) provided more demanding conditions.  The rig for our transatlantic crossing will need to be able to withstand the worst conditions the Atlantic Ocean can provide. During a storm this could be 50 knots with 12 meter crashing waves.  These conditions are a huge design concern and set apart the Transat boat from previous Sailbot’s, and the rig definitely needs to be re-thought.

The next option brought to the table is a fixed wing, a new technology famously used in the 2013 America’s Cup’s boats.  This design could prove to be a huge advantage and could possibly be designed to have 360 degrees of freedom.  A huge drawback to fixed-wing sails is they are very new technologies with limited information available.

After further research, we “re-discovered” the windsurfing sail. Windsurfing sails are very robust, designed for demanding scenarios, are already designed and come in various sizes and qualities. After meeting and discussing with our advisor, Don Martin, we reached an “AHA” moment when we revealed that both our personal research led us to a windsurfing sail!

Below you will find summaries of the different technologies we looked at.

Main & Jib Sails

Greg and Adrian launching the Thunderbird 2012 robotic sailboat in the summer of 2012. UBC SailBot's Thunderbird 2012 has main & jib sails.

Greg and Adrian launching the Thunderbird 2012 robotic sailboat in the summer of 2012. UBC SailBot’s Thunderbird 2012 has main & jib sails.

Ready Technology: Yes.

Number of Sails: 2

De-powering:  Luff (let out) both sails.

Durability: A luffing sail will eventually tear.

Other:  We have experience building and using these!

Fixed-Wing Sail

Fixed-Wing sail. Photo by  ** RCB ** (Flickr)

Fixed-Wing sail. Photo by ** RCB ** (Flickr)

Ready Technology: No, a lot of research and designing is needed.

Number of Sails: 2 (looks like one, but acts like two).

De-powering: Alter one sail flap, or both.

Durability: Very durable and streamline, will not luff.

Other: These are so cool!

Windsurfing Sail

Windsurfing rig. Photo by Filipe*Fonseca (Flickr)

Windsurfing rig. Photo by Filipe*Fonseca (Flickr)

Ready Technology: Yes.

Number of Sails: 1

De-powering:  Luff sail.  Square Top sail allows for self-depowering in lower winds.

Durability: Designed for extreme conditions.

Other:  We can easily pick, choose, and test various rigs as these are off the shelf products!

Conclusion

The best candidate for the Transat boat would be a fixed-wing sail; however, this would need extensive research, testing, expert building techniques, and much iteration to ultimately create our rig.  Since we do not have enough time, money, and expertise, a windsurfing rig appears to be the best candidate and is the design we will be using!

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