Isthmus University

Welcome to Isthmus University

Whether you're interested in Windsurfing, Foiling, Winging, or all three, Isthmus University will teach you everything you need to know about selecting the right equipment for you! 


Sifting through windsurfing board and rig options via web, catalogs or in person, can be a challenging process. Understanding various board and rig designs, shapes, sizes and features can be overwhelming. This is especially true for beginner to intermediate sailors who are new to the sport or those who've never purchased their own gear. Talking directly to experts who address windsurfing customer questions of all levels on a daily basis will serve you best to personally guide and clarify your options.

For those of you who desire to research gear on your own, we've created Windsurfing 101. It is a list of terminology, board and rig examples and options to help you get started on your path to windsurfing board and rig ownership. We hope it will help you gain a clearer perspective of equipment options you may want to consider.

- Isthmus Sailboards Staff


Volume – This is the amount of floatation (buoyancy and weight carrying ability) the board contains. This is especially important for low wind conditions where higher volume will support more weight when learning windsurfing and low speeds are involved. Volume is measured in liters. 1 liter = about 1.8-2.0 lbs of positive floatation (fresh water vs. salt water).

Fin / Skeg – The rear most fin on bottom of the board. This generates lift and assists in directional control of the board. The larger the fin the more lift it generates (ideal for bigger sails and lighter winds), the smaller the fin is the less lift it creates and more maneuver and smaller sail oriented it is (ideal for learning and or stronger wind use).

Dagger Board System – This is a retractable fin that is located in the mid-section a windsurfing board. It is usually 50 -78 cm (18 – 30") in length and features a range of motion of 0 to 90 degree rake angles that can be adjusted up or down while sailing. Down (90 degree) position will maximize stability, lift, up-wind pointing performance and minimize side slippage (down wind drift). The Up position (fully retracted into bottom of board) will assist you in achieving faster speeds and planing qualities when the wind conditions exceed 10 mph.

Mast Box – This is the area that your rig connects to your board. Modern boards have a mast box that is a slotted channel in deck of board. It is designed to allow a t-nut on the end of a base (see base description below) to insert into the channel and then allow the base to be twisted on to secure it into the mast box.

Fin Box System – This is the type of connection for the fin base into the board. US box = slotted groove. Power box = double hump base with center screw location. Tuttle box = rectangular base with two screw locations. DT box = deeper / larger area Tuttle base with two screw locations.

Foot Straps – These are attachments to insert your feet into when windsurfing in strong winds while the board is planing. Most models of board we sell include a set of foot straps.

The Rig – This is the common reference to the combination of the Windsurfing sail, mast, boom, base and base extension, when assembled together.

Sail Sizing – Windsurfing sail sizes are determined by square meter area. (1 square meter equals about 10.76 square feet.) Sail sizes typically range from 2.0 to 10.0m2. Adults learn best with 4.0 – 5.5 m2 sail sizes.

Sail Type – Most windsurfing sails have full length battens (to support the sail cloth), are built with sail cloth materials that include monofilm, Dacron or x-ply, and are mostly transparent to allow good visibility of your surroundings. Full batten sails are commonly referred to as No-cam, Freeride, Bump-n-jump / Wave, or Recreational sails.

Mast – This is the spine (support) for a windsurfing sail and inserts into the leading edge of sail (mast sleeve). These are available in Epoxy and Carbon constructions. Its length is measured in centimeters. Average length is 460 cm (15'1"). Most sail sizes below 6.5 m2 require a 430 cm mast or shorter length, and above 7.5 require a 490 cm mast or longer. Most masts are 2-piece models for ease of transport.

Boom – It is your hands on to control the power of the sail and direction of your board. All modern booms have a clamp-on front boom head for ease of attaching it to the mast and positioning relative to user height. They are adjustable in length to accommodate a range of sail sizes and are measured in centimeters for length. Average booms are 160-220cm lengths (5'3"-7'3").

Base and Base Extension – The Base is what connects the board to your rig. It has a rubber or mechanical mid-section that allows your rig to turn 360 degrees and pivot at up to 90 degree angles to the board. The Base Extension is what connects your mast and sail together. It is a key part that allows you to properly rig and tension the sail. They are available in 15, 30 or 48cm adjustment range options. The top of the base connects into the bottom of the base extension.

Uphaul – Is a knotted tubular webbing rope that attaches to the front end of the boom and the base of the sail. It is a necessary part to allow windsurfers to lift the sail up and out of the water, especially when learning.

Recreational Boards:
Modern recreational boards are ideal for learning to windsurf and allow for rapid progression to intermediate skill levels and beyond. Each model offers a high degree of stability proportionate to its size. Modern recreational boards achieve this through board width of 30" or more and a dagger board system. The dagger board system allows riders to control the center fin lift while under sail based on the riders' needs and desires. Down position will maximize stability, and minimize side slippage. Up position will aid you in achieving faster speeds and planing qualities when wind conditions exceed 10 mph. The recreational boards we offer are designed for use in a wide range of wind conditions and many feature a durable plastic skin construction.

General overview:
- Recreational Board Sizing: 160 – 266 liters
- Wind condition range: 2-20 mph
- Sail size range: 2.0 – 10.0 meter - optimal 4.0 – 7.5
- Skill level – Beginners - Intermediates

Recreational Rigs:
We offer rig packages that are ideally suited for a range of skill levels from entry level kids to advanced level adults. Each rig package includes all the necessary hardware to complete and attach the rig to a windsurfing board. The size rig you select will have a direct impact on ease of use, available power, wind range and comfort. Most Kids Rigs range from 1.0-3.5 m2, while Adults Rigs will range from 4.0-7.5 m2.

Complete Package Options:
For your convenience, we offer a combination of board and rig options that are sold in complete packages. Click here to see our current complete recreational package options.


Equipment Selection, Terminology, and Complete Packages COMING SOON!


Equipment Selection, Terminology, and Complete Packages COMING SOON!

If you have questions or want assistance in choosing the right equipment for you, please don't hesitate to contact us!