From the Experts; The Benjamin 505

Article taken from Yacht Racing/Cruising Magazine

by Steve Benjamin
Photos by Shimon-Craig Van Collie & Barry Pickthall

Steve Benjamin shares some of the go-fast ideas that helped him win the 1980 505 World Championship and which can also be applied to other high- performance classes.

Original images from magazine below as well as full text following.

The 505 is an extremely exciting and gratifying trapeze dinghy. Its large sail plan and narrow waterline beam basically make it overpowered in 15 knots of breeze (even with my crew, Tucker Edmundson, at six feet, four inches and 195 pounds, plus a three bottle water jacket). In lighter air the 505 is truly high performance, rewarding both skipper and crew with its responsiveness to helm and crew movement. Fundamentally a development class, the 505 has been and continues to be a leader in innovative construction, equipment and rigging design.

The Hull

When getting started in the 505 class the potential skipper has a number of choices to make. Chief among these is whether to purchase a bare hull and install all the hardware yourself, buy a new boat fully equipped or buy a proven used boat. No matter what the choice, ifs important that the prospective boat be near minimum weight with a stiff and fair hull. Recent advances in construction made possible by epoxy resins, Kevlar and carbon fibers and improved coring materials, have resulted in a new generation of 505 hulls that are both lighter in the ends and stiffer in panel and in ability to handle rig tension. The leaders in these advances are Mark Lindsay Boatbuilders of Manchester. Mass., Hamlin Boats (now Waterat) of Costa Mesa, Calif., and Parker UK. Ballenger Boats of California is also reportedly developing a "high-tech" 505. Most of these builders, and others, will provide you with a fully rigged boat at a price that is probably cheaper than you could do it for yourself. The question is whether you agree with the builder's layout or prefer to implement your own ideas, as most 505 sailors do. In our case, the fitting layout was essential to overall rig control, so Tucker and I chose to fit the boat out entirely ourselves.

Spar and Sail Selection

Next to the hull, the spar and sail combination is crucial to superior boatspeed. Although exotic materials and rotating rigs are permitted in this experimentally minded class, at present few successful 505 teams are using them. And while the class is often on the verge of a breakthrough, the over- whelming majority of top boats are currently going with the standard Proctor D section mast. A newer D-plus section with thicker sidewalls that is stiffer in the athwartships direction, making it an interesting spar because of the 505's long unsupported tip. may prove successful in future tests. Hut the big advantage of a standard I) is that your choice of sails is easier, since all the major sailmakers for the class have compatible designs for this section. Sobstad, Musto and Hyde, Pattison, North and Hood are the most popular, and all have their own unique features. We used a Sobstad all around main and a Sobstad heavy-air main at the worlds and found an advantage in having specialized designs, even though we occasionally got caught with the "wrong"' sail up.


Consistent with its developmental spirit, the 505 class allows sailors a free choice in centerboard and rudder configuration The only requirements are that the blades be symmetrical and that the board fit within the trunk when fully raised. Rudder design has become fairly standardized, with parallel sides, a vertical leading edge, a 3.25:1 aspect ratio and it extends 28 inches below the waterline. This shape seems to steer nicely in all conditions with no stall.

Centerboards, on the other hand, have been the subject of great experimentation. Absolutely the best proven and most universally accepted design is the "elliptical." This board features a vertical leading edge coupled with a sharply rounded trailing edge on the lower section, which terminates in a virtual point at the tip. Reminiscent of a bird's wing, the elliptical-shaped board is at its best in moderate to heavy air. Since the class allows changing boards during a series, we also experimented with the "high aspect" profile. This board is deeper and narrower near the hull, wider near the tip and has a rectangular bottom. In light air we found it quite f3Sl. but as soon as the breeze came on, the boat felt too overpowered and would not groove properly. Ingenious sailors in the class have tried for the best of both worlds by installing a vertical lifting pin that rides in a track recessed into the inside of the trunk. When overpowered, a control line can be pulled, raising the board vertically and substantially reducing area. While this system sounds pretty good on paper no one has proved it an advantage over the elliptical shape, which took at least the top two places at the '80 Worlds and won the '79 Worlds. Both the elliptical and high-aspect designs are jibing boards and neither can be pulled up for heavy-air beating (by pivoting, not vertical lifting) without an unmanageable increase in leeward helm.


505 sailors differ greatly in their opinions on how the rig and sails should be controlled. Existent in the class are several veterans with fixed ideas that have always seemed to work fairly well. But Tucker's and my experience in other classes influenced us to take a fresh look at the inherent problems, and I believe we came up with a number of innovative solutions. Perhaps chief among these is my contention that the shrouds should enter the mast at the same height as the jib luff wire (which is always placed at the class rules' maximum height). Most, if not all, of our competitors rig their shrouds at least 12 inches above the jib luff wire entry, claiming increased sideways stiffness, less tip fall off and greater response to rig tension as advantages. But, offsetting the shrouds from the lull wire in this fashion necessarily increases upper fore-and-aft bend when the rig is tensioned. The more tension the more upper prebend, which requires the mainsail to be cut with more upper luff curve to accommodate the shroud/luff wire set up, Working closely with our sail- maker, Tucker and I tuned our rig with the shrouds at the same height as the jib luff wire. The result was that we eliminated upper prebend, allowing a much more controllable mainsail shape. Thus we were able to isolate the two very important variables of jib sag and mast bend, unlike the standard rig which necessarily adjusted both at the same time. Our mast may bend sideways more, but this never produced a lack of power — Tucker was always The first crew on the wire. This was undoubtedly due in part to the height of our trapeze wires, which remained at the old shroud position, some 12 inches above the hounds. Further, it's my contention that our rig will accelerate the boat faster in a puff, because there is no tendency for fore-and-aft bend to increase (opening the leech) with greater load.

Since our low hounds position effectively locked the mast in a straight position, we needed a device to adjust upper mast bend for various conditions. The answer was traveling shrouds Both shrouds terminate on a traveler car/track arrangement which is led aft and controlled by the helmsman. As the cars are eased forward, upper prebend increases (just like swinging the spreaders aft) —useful in light air. flat water or when overpowered. With the cars fully aft, the mast bend actually reverses in its upper section (until mainsheet and vang pressures are applied) The result is a very straight spar, producing a full and powerful mainsail shape which is ideal for chop and underpowered conditions. The ultimate adjustability of our rig should now be apparent: jib sag. as required, is set by rig tension: upper bend, positive or negative, is set by shroud position.

Another important innovation which I borrowed from the 470 class, is the dual car traveler. Most 505s are equipped with a bridle or split-rigged mainsheet system. Both of these are imprecise in that they do not allow perfect centering of the boom for light air and are slower to adjust for changes in wind strength. With the dual car traveler system, the leeward car is released (until heavy air when both cars are fixed to form a bridle) and the windward car is positioned so that the boom is centerlined and the leech is flowing, as indicated by stall telltales at each batten. Minor changes in wind strength require only adjustment of the mainsheet — with the standard rig, a change in both vang and mainsteet tension is required. And while the traveler system may be more difficult to tack, because the new windward control has to be brought up on each tack, it offers more choices in mainsheet purchase for offwind legs. As the wind increases, the ability to center the boom is no longer important and the traveler cars are fixed about eight inches off centerline, form- ing a standard bridle. The vang then becomes the primary control — the more wind, the more vang, until totally overpowered. As a puff hits. I increase vang tension, ease the main to keep the boat from heeling and drive off slightly, which facilitates windward planing. On a tight reach, the vang acts as a throttle to control power more vang gives more power; if over- powered in a puff, let the vang go.

Most 505s are equipped with some means of lower mast bend control. Many English boats, including three-time world champion Peter Colclough. employ simple mast blocks at the partners to restrict bend. Tucker and I prefer a fully adjustable strut that pivots on the foredeck and rides on a traveler car/track on the front of the spar opposite the gooseneck An 8:1 tackle pulls the strut down reducing bend and a 4:1 tackle pulls it up to add prebend for light and very heavy air (many 505s can not control lower prebend as their struts can only be pulled down, not up). It's also important to be able to prebend for heavy-air running to prevent the mast from inverting, which is how we lost our 470 rig at Kiel Week.


While individualized settings should always be sought, we offer the following numbers as a rough guide: Rake—25 feet, eight inches, measured with halyard locked, through tiller port, to intersection of transom and bottom at centerline. Rig tension -350 pounds on the headstay. 500 pounds on the shrouds. Centerboard pivot position-eight feet, seven inches from aft side of transom. Mast step -10 feet, one-and-one-half inches from the aft side of the transom to the face of mast in step. Spreaders — 10 feet, three-and- one-half inches above deck. 14 feet, three-and-one-quarter inches long and a four-inch deflection (measured to the aft side of the mast from a tip-to-tip straight line). Adjusting the sails and rig for optimum speed on the 505 follows normal tuning ideas. The boat sails best with a neutral or very slight weather helm. The board should always be front-edge vertical and the boat kept very flat in general and when testing helm. In chop, the sails should be made fuller by reducing rig tension, allowing more jib sag (and less bend in standard rigs). The mast is straightened by pulling the strut down and sliding the shrouds back if possible. We achieved this combination by increasing shroud tension with our Sta-master turnbuckles before the race. The outhaul should be firm, and weight can be moved forward, lengthening the waterline. Jib leads 3re moved slightly aft and the sheet trimmed harder to create a flatter shape. In overpowered conditions, the fastest boat at the worlds was John Andron and Howie Hamlin. They claimed to use extreme rig tension, which should have reduced jib sag (producing a Hatter jib) and forced them to carry the exaggerated fore- and-aft bend produced by the offset shrouds and jib luff wire. Their jib was trimmed hard with the leads well aft.

Our rig could have been much lighter, but the other settings agreed with the Andron/Hamlin conclusions, giving us speed second to theirs, but superior to everyone else's.


The old saying of "sail it flat" certainly applies to the 505. Only in very light air should the boat be heeled slightly for helm and to reduce wetted surface. The 505 should be roll tacked and roll jibed in all conditions, though in heavy air it's more a case of the boat roll tacking you.

Upwind, the crew should adjust his weight to keep the bow (at the knuckle) just touching the waves, unless it's extremely Hat water when both skipper and crew can slide for- ward. The same principle applies to reaching. On a run the boat can be sailed amazingly close to dead down with a large spinnaker, but it must be reached considerably more with the smaller, flatter chutes. Spinnaker handling is one of the keys to improved performance in the 505. We eliminated the chute launcher in our boat to get the spinnaker up faster and keep weight out of the bow. The problem comes at the end of the reach when the crew has to come off the wire to put the spinnaker away. Boats with chute launchers can suck their spinnakers in with the crew on the wire and never stop planing. With either system, however, the important thing is well-practiced crew and helm coordination, along with judicious choices of when to set the spinnaker. If a reach is too tight for a proper carry, many places can be lost by attempting it Conversely, if it is possible to lay the mark or even come close, then the best plan is usually to set the spinnaker right away, sail as last as possible and then take it down at a fast jib reaching angle if necessary. And many times the air will lighten or shift aft, making it possible to keep the spinnaker up right to the mark.

Jibing the 505 reach to reach is perhaps the scariest maneuver I've ever encountered on a small boat, in heavy air. but it needn't be. With the use of twings and the following procedure, the risk is greatly reduced:

1. Crew hands skipper sheet from wire, jumps into boat as skipper bears off. Skipper has main cleated in slightly cased position.
2. Crew pulls in and cleats new twing. Simultaneously, skipper eases and then cleats sheet on centerboard cap at predetermined mark (so that old clew (new tack is next to headstay). 3. Crew removes pole as skipper takes up slack on old guy and cleats on side tank.
4. Skipper jibes boom with mainsheet as crew balances boat until jibe is completed and boat stabilized
5. Crew pushes out pole into position as skipper eases new guy and cleats in reaching position.
6. Crew jumps back, takes sheet, eases twing, takes up slack in sheet and goes out on wire.
7. Skipper adjusts main trim, fixes jib sheet.

In reviewing the above steps it should be remembered thai the 505's spinnaker pole is so long that it cannot be easily end for ended on a jibe and hence is stowed along the boom before the jibe by means of a trolley or retractor system.

Once improved boathandling and boat tuning arc combined, the 505 becomes a rewarding boat to sail Not only is it exciting because it's one of the fastest small boats, but also because perfection in handling, sail setting and myriad other factors are immediately realized by superior speed. The developmental tendencies of the class are refreshing and always of interest to sailors in a wide variety of small boats. The recent growth of 505 sailing in North America is certainly well justified and hopefully a trend that will continue and spread world-wide.