Article courtesy of Harken Yacht Equipment.

Analysis of MedCup Top Three – Engineering Brief from Harken

What did the top three TP52s in the Medcup have in common? What makes these impressive machines tick? The Medcup consists of five events in different countries and many different sailing conditions—from light winds in Spain, to gear-breaking breezes in Portugal. To win, competitors need an all-round boat and reliable hardware. Each of the top three overall Medcup finishers are fully-Harken equipped with the latest in carbon winch systems and Grand Prix hardware. Two of the three boats took it a step further and experimented successfully with the award-winning Pro-Trim traveler system (Artemis and Patches). “Campaigning these boats is like managing a mini America’s Cup program,” explained Peter Harken. “Harken dedicates one of their top-notch technical support teams to these programs,”.

HISTORY

Harken has enjoyed great success with the exciting TP52 Class. The new Transpac 52 box rule has no real restrictions which is what has made this trip so thrilling, allowing Harken to trickle-down what they have learned from their last three America’s Cup wins and the Volvo Ocean Race, into a smaller, but still powerful box rule package. To date 34 TP52s have been fitted with Harken's versatile winch and hardware systems configured for both offshore and buoy races.

The evolution of the class, particularly the winch and hardware systems, is quite astounding, especially because it happened within such a short period. Harken has been there from the first boat, and they look forward to continuing to participate in the development of this class.

WINCH SYSTEMS

Since the first boat in 2001, the TP52 has undergone four generations of winch layout. However, there are just two Harken sizes specified for the latest TP52s: the 65 and 50. The 65 is used as the primary, mainsheet and backstay/secondary winch, the 50 for halyards and backstay.

In its ultimate form, the 65 winch is built with titanium gears and carbo drum, with a machined 6061 aluminum housing. Harken supply this configuration to AC, Volvo and Open Class Maxi boats as a halyard winch.

For the TP52 class and other IMS, ILC classes, Harken is required by class rules and smaller budgets to build their 65 winch family with gears cut from stainless steel, and machined 6061 aluminum drums, housing and base. For self-tailing and top-cleat systems, Harken drums have carbon components.

65 Winch Family

The 65 winch family comes in various configurations: two-speed self-tailing, three-speed self- tailing and three-speed top-cleat. The three-speed winches (both self-tailing and top-cleat) have a unique first gear ratio of 1:1 (one turn of the handle = one turn of the winch drum). This 1:1 gear ratio is necessary when coupled with a pedestal, especially for mainsheet trimming with the self-tailing.

Left: The 65.3 TCR also available with an optional ratchet base sheave for cross sheeting and lazy sheets.

The primary winch on a TP52 is the 65.3 TCR, also available with an optional ratchet base sheave for cross sheeting and lazy sheets. It is always linked to a pedestal. For the mainsheet winch most boats use the 65.3 STR which may or may not be linked to a pedestal. The 65.3 STR is the only self-tailing winch this size with a 1:1 gear ratio.

Backstay Winches

Backstays are adjusted hydraulically or on a winch, with most crews opting for the winch because it is faster and allows the main trimmer to shift gears more quickly. With a generation three layout, the larger 65.2STR winch is used for the backstay, and as a secondary winch for in-line jib changes and spinnaker peels. In a generation four layout, the smaller 50.2 STR (4:1 ratio for first gear) is used with a 4:1 block and tackle for the backstay.The mainsheet winches with mainsheet jammer are used as secondary winches.

Halyard Winches

There are two halyard winches on a TP52; most common is the smaller 50.2 STR with a 2.7:1 gear ratio for first gear. This fast ratio is helpful for trimming the spinnaker sheet during gybing duels. Some teams are fitting a larger 65.3 STR on the starboard side of the pairing providing a faster first gear for the spinnaker downhaul.

Pedestals

Harken pedestals are built from carbon prepreg material, vacuum bagged and autoclaved. They are available in many different lengths and angles and even twisted versions. Pedestal handles are easily removed to clear the cockpit and flake the mainsail after racing. Drive shafts above or below deck are 50.8mm (2 inch) carbon tubes with lightweight couplings bonded on with aerospace epoxy. Linking the drive shaft to the winch is the small lightweight 605 bevel gear box. At 2.3 kg (5 lb), it fits in your hand, and will withstand a four-man input. The gear boxes are machined from solid aluminum with carbon cover plates to seal the stainless steel bevel gears and roller bearings.

LAYOUTS

Generation One

These offshore boats were designed specifically for the Transpac Race to Hawaii. The design criteria were they should be lightweight and simple, with maximum headroom below decks. Yassou, Rosebud, Lightwave, Flash, and Trader, fall into Generation One . Harken designed a system that utilized one pedestal to drive the primaries, with drive shafts above deck for extra headroom below.

The boats were set up like a typical IMS 50 footers. Two halyard winches, two primaries linked to a single pedestal, two mainsheet winches with a full 2:1 German Admiral's Cup dedicated winch mainsheet system and a set of secondary winches for in-line changes and peels. A great all-around system, but short on horsepower when competing with the latest generation around-the-buoys-especially in gybing and prestart maneuvers.

Image: The Reichel/Pugh-designed Rosebud was designed for the Transpac.
Generation One Winch Layout Drawing Photo: Billy Black


Generation Two

Beau Geste and Braveheart took the winch system to the Generation Two level, with two unlinked pedestals. The primary pedestal linked belowdeck to the primary winches and the mainsheet pedestal linked above deck to one centerline winch. Crews had realized how powerful and big the mainsails were on these boats, and how important it was to have a pedestal, especially during prestarts, gybes and to pump the main while surfing. This pedestal system also allowed the mast man to concentrate on the bow, and not have to jump the sheet at the gooseneck. With a single centerline mainsheet winch, the cockpit was also easier to manage because it eliminated the need for a second body to leeward during roundings.

Image: The Bakewell/White-designed Braveheart features two unlinked pedestals.
Generation Two Winch Layout Drawing Photo: Sharon Green

Generation Three

Esmeralda started the Generation Three trend in winch layouts. This soon prompted similar setups by Sjambok and BrightStar . Project Manager Bob Wylie, a veteran of multiple America’s Cups, 50-footer and Maxi campaigns, worked with Harken to develop a more versatile winch system that would incorporate additional technology from recent America’s Cup projects, and would suit both distance and buoy racing. To gybe faster, and to give crew more ability to trim the large mainsails, we proposed a T-shaped layout consisting of two pedestals linked together to drive both the primary 65.3 TCR winches and one mainsheet 65.3 STR. Two 65.2STR secondary winches were used to trim the backstay and act as secondary winches with 50.2STRs for the halyards.

Image: The Farr-designed Esmeralda features a T-shaped winch layout that incorporates technology from recent America's Cup projects. Generation Three Winch Layout Drawing Photo: Billy Black

Overdrive Gear Boxes

To accelerate the gybe, the boats now had four grinders linked together into one winch to increase input torque. However, they were still working with human power, and even with multiple pedestals linked together, the maximum power a human can generate is 200rpm. That equates to a winch line speed of 94m/min. With the first gear of 1 :1, the line speed was still too slow.

To solve this, Harken fitted Esmeralda with their 605 overdrive gear box, a smaller four-man version of the America's Cup eight-man overdrive box. This box mounts to the forward side of the twisted pedestal, and accelerates the input to the winch. When turned ON (by hand control with a Harken cam cleat mounted in the pedestal), the input accelerates by 2.4 times (Gear Ratio [GR] of 1:2.4). Now with the winch in first gear (1:1GR) and in overdrive (1:2.4 GR), 1 turn of the handle generates 2.4 turns of the winch drum. This equates to a line speed of 225m/min. That is FAST, and you better have a really good trimmer to keep up with all that rope coming at him!

The overdrive box also provides the grinder with six speeds to choose from. The standard 65.3 TCR winch has ratios: 1:1, 4.5:1, 19:1. With the overdrive ON, these ratios become 1:2.4, 1.8:1, 8:1. Having these other gear ratios is very useful, especially for distance races when a non-grinder type might be on the pumps; he or she should be able to find a comfortable trimming gear for whatever sail is being used at any one time.

Image: The overdrive box also provides the grinder with six speeds to choose from. The standard 65.3 TCR winch has ratios: 1:1, 4.5:1, 19:1. With the overdrive ON, these ratios become 1:2.4, 1.8:1, 8:1. Photo: Mark Wiss

Generation Four

The latest TP52s have taken the Esmeralda "T" system to Generation Four -the "H" system. Many mainsheet trimmers debate the effectiveness of one mainsheet winch on centerline, versus two mainsheet winches (one port, one starboard). A centerline winch means one grinder off the rail to grind. Two winches, mean the trimmer can grind to weather, with his pedestal grinder also on the rail. Add jammers and you also have spare secondaries for in-line changes. Generation three and four layouts were both current in 2005, with the choice depending on a crew’s sailing style, the mainsheet trimmer’s preference and the racing schedule—offshore vs buoy events.

Generation Four boats like the Farr-designed Bribon use the "H" system.
Generation Four Winch Layout Drawing Photo: Jorge Andreu

DECK HARDWARE

Loups™

Hardware systems on the TP52 are a rigger's dream! Today's advanced rope technology allows Harken and yacht designers to work together to build simple, reliable, and very lightweight systems. No longer do riggers attach blocks using shackles and toggles. Instead products like LOUPS make "soft attachment" technology easy and reliable. The TP52 uses Harken's Black Magic® AirBlocks® for mainsheet, spinnaker, brace, backstay and mastbase blocks. The AirBlocks® use caged Torlon® roller bearings, for easy service. High efficiency Straphead blocks work with LOUPST for a soft attachment to Harken's soft padeye for significant weight savings. No more fasteners, shackles, or headposts. No more heavy metal!

Of course there is no substitute for the Harken Carbo blocks and Cam-Matic® Cam Cleats used throughout the boat for control lines and purchase systems.

CRX Roller Traveler

The TP52 uses Harken’s patented CRX Roller Traveler car for a highly efficient system that allows its giant mainsails to be trimmed by hand, not winches. Because the captive roller bearings have a larger bearing area compared to the point loading of a ball bearing, we can use a shorter car to carry the same mainsheet load. This translates into a lighter car with more travel. Finally, when the car is removed, the captive bearings won’t fall out.

Code Zero Furling

The giant over-lapping headsails on the TP52 furl onto the Harken Code Zero-Unit 2. The lower unit uses a continuous line to drive the drum, with the same successful tooth-design technology Harken use on their dinghy ratchet blocks. A short bearing housing sealed from the elements protects the carbon steel thrust bearings, allowing maximum luff length. Attachments are available to make this a 2:1 or snap shackle purchase.

Jib Leads

Jib lead systems vary from boat to boat. The earlier generation TP52's used a standard Harken Big Boat fore/aft track system, with a #554 ball bearing car and an in-hauler sheeted closer to the cabin house. Second generation boats like Esmeralda, used a custom ball bearing car with LOUPS technology and captive ball bearings for a significant weight savings. Recent designs have shifted from fore/aft tracks, to athwartship systems. These use the C7004 Big Boat CRX car (call Harken), and the C7251 wide-sheave floating Black Magic® AirBlock®.