The following is a magazine extract from the November 1982 issue of Cruising World:
For Cruising World's 1982 Design Competition, we were looking for a new and innovative trailable gunkholer, designed for use on protected waters and with accommodations for at least two people. For ease of trailering and launching with a small car, a maximum trailing weight of 1000 pounds was specified. Other requirements were a maximum draft of 12 inches and a beam of 8 feet or less, dry stowage for food and clothing and some form of auxiliary power. Accommodations could be permanently enclosed, or partially enclosed, with a tent or canopy. Important considerations included performance, crew comfort and ease of rigging.
We received over 30 entries, representing a great variety of type and size. Members of Cruising World's editorial staff along with naval architect Yves Tanton and Jeromy McGeary from the Pedrick Design Office, spent hours considering and discussing the designs before choosing this 21-foot catamaran submitted by James Wharram and Hanneke Boon.
Wharram has worked with catamarans of this size for more than 20 years and thus has a vast amount of experience on which to base this new design. The TIKI 21 is designed for those who have no desire for, or cannot afford, a boat to cross the oceans. She is intended to cruise along the coast and in bays, rivers, estuaries and lakes.
In creating the TIKI 21, Wharram has used what he calls "appropriate technology - not 'high' or 'low' " achieving the desired levels of performance, comfort and safety while at the same time keeping the craft simple and relatively inexpensive to build and maintain. He eliminated from the boat, wherever possible, 'the expensive, glittering metal fittings common to modern yacht design'.
TIKI is constructed of plywood, with joints stitched with copper wire, filleted with epoxy filler, and fiberglassed with cloth and epoxy resin. All exterior surfaces are sheathed in cloth and epoxy. Eighteen sheets of 1/4 inch plywood and one sheet of 5/8 inch are required. All parts are pre-coated with resin before assembly. Even the l-shaped crossbeams are built up in the "stitch and glue" system.
A construction time of only 300 to 400 hours is predicted by Wharram. This means that someone who could devote 20 hours a week of spare time to building TIKI could complete her in about four months.
The centre platform and crossbeams are secured to the hulls with a lashing system, eliminating any hardware and requiring only 10 minutes to perform. There is no danger of sand or dirt jamming a tight fitting joint. Even the rudders are lashed to the hulls; no pintles or gudgeons are needed. Mooring cleats at the ends of the crossbeams prevent the lashings from slipping. Bow and stern handles are built in to the stern and sternposts.
Draft for the TIKI 21 is 2 inches greater than the 12 inch requirement, but the judges felt that because the boat is taken apart for trailering, with each hull weighing 175 pounds, it can be launched by hand and therefore not be disqualified on this count. For trailering, the hulls can be carried alongside each other with the platform on top. It's folding tent can be lifted off and used to camp in on the way to the launch site.
Each V-bottomed hull contains a 22 inch-wide berth with stowage underneath and at either end. Additional stowage, accessible only through a deck hatch, is located forward of the berth in each hull. There are watertight buoyancy compartments positioned in the four ends.
A unique hatch design allows use in a number of positions to give partial protection to the helmsman, seal off the hatch entirely, or admit as much light and air as possible. All this with no hardware!
At anchor, the "folding pramhood" deck tent shelters the expansive deck platform with 4-foot, 6-inch headroom, or 5-foot, 7-inch headroom if standing in either hull. An outboard motor can be fitted to a well at the middle of the after edge of the platform.
The innovative gaff sloop rig features a high aspect mainsail with sleeves for the mast and gaff. Halyards run down inside the luff pocket. The loose-footed mainsail sheets to a full-width bridle at the stern. Wharram claims quite high performance for this aerodynamically clean gaff rig, saying "speeds of 8-13 knots can be reliably expected".
Calculations by Wharram, using dynamic rather than static wind forces, show that the boat will be stable with full sail in up to about 30 knots of wind, and with reefed main and jib to about 35 knots. On the subject of seaworthiness, Wharram says, "In a small boat it is very much the function of the skipper. TIKI's 22-foot and 23-foot predecessors have crossed oceans and rode out gales and hurricanes. In spite of that, please don't build a TIKI to cross an ocean, yet it is nice to know that it has seaworthy potential"
Wharram offers extremely detailed building instructions for the TIKI 21. He feels that self-building a boat is a "last freedom" in this age of bureaucratic restrictions, and that it releases many hidden frustrations. Since most people have limited building skills, the construction method and instructional drawings are of great importance. In addition to step-by-step illustrations (clearly done by Hanneke Boon), he discusses the choices and uses of materials and tools.