In 1991, the group approached international naval architects to create a new Cork Harbour One Design. It was intended to replace the famous class designed and built in 1895–96, which raced in Cork until the 1960s. Tony Castro drew the boat that became the Cork 1720. By the time boats.com tested her, around 100 boats were on the water, and 70 had lined up for the start at Cork Week 2000.
Design and Construction
The 1720 is a fractional-sloop monohull measuring 8.0 m overall with a 2.5 m beam. Its solid fiberglass hull is built with stitched and woven glass reinforcements laminated in Vinylester resin, while the deck has a balsa core. The resin choice is expected to help the solid hull laminate remain tough and durable.
A 630 kg lead bulb keel provides the righting moment. That is a substantial share of the boat’s 1,200–1,250 kg displacement and gives the 1720 the stability a one-design racer needs when pressed. She’s no lightweight, but carrying so much lead in the keel provides plenty of righting moment for the rig above.
Rig and Handling
Upwind, the 1720 carries 42 sq m of sail area—a generous amount for her length. The sail plan includes two jibs, both sheeted to a single track through a two-to-one sheet and ratchet turning block. The choice of two jibs and a couple of deep reefs allows the crew to regulate power upwind.
The substantial mainsail keeps the boat moving in light air, but the 1720 needs to be sailed flat. As soon as she heels, the crew must ease the mainsheet or traveller. Otherwise, a mild broach follows. Preventing that broach requires constant sheet easing when the boat is heeled, although recovery is quick.
Downwind, the immense 68 sq m asymmetric spinnaker forces the boat onto a deep angle. In moderate air, that keeps her outside the high-performance planing envelope: she was relatively slow to accelerate and reluctant to plane. In more breeze, however, the hull form will rise onto a plane, and later reports credit the 1720 with rapid downwind pace in a blow. The smaller, short-hoist spinnaker proved the better option in medium air, nearly matching the larger sail’s drive while producing less heeling moment.
Cockpit and Below-Deck Space
The 1720 is virtually a day boat. Its open cockpit accommodates four or five sailors, but below decks there is only cramped storage—an estate agent wouldn’t call it accommodation. The space is essentially empty and awkward to enter. It can hold spinnakers and warps, but getting a mainsail in and out is difficult.
Short, deck-level guard rails prevent the crew from sitting facing outward and limit hiking. Foot braces help shorter-legged sailors stay in place when the boat is upright, but they don’t provide the same support at large or extreme angles of heel.
Deck Layout and Known Issues
The deck layout makes it nearly impossible to work the boat with the hatch open. That helps avoid J24-style swamping, but it also complicates access below.
Testers found the haphazard positioning of the deck fittings a major obstacle to enjoying the boat. Around the mast base, control lines and halyards led to almost the same place with little apparent logic, leaving the working area crowded. The mainsheet and backstay cleats were difficult to operate from the rail and required a firm shove with a foot. The backstay itself appeared to need a fundamental rethink before it could work effectively.
On either side of the winch pod is a vast stowage bin that makes launching the spinnaker simple. However, the bin on either side has no top, so the spinnaker can cascade over the side during a takedown. Canvas flaps and elastic would solve the problem.
Ownership and Refits
The 1720 is a controlled-spec one-design racer intended to provide affordable, competitive sailing. Four or five ordinary sailors can race it without terror or boredom, although the large sail area and need to keep the boat flat call for a fit mainsheet trimmer.
Adding canvas and elastic to the spinnaker bin is a minor job. Otherwise, ownership centres on maintaining the boat within its controlled one-design specification. With around 100 boats afloat by the time of the review and a strong fleet at Cork Week, the design fulfilled its market.
The Verdict
The 1720 is a purposeful Irish one-design that trades outright screamer performance for easier handling in club racing. It is solidly built in Vinylester, with a lead bulb keel and a large but manageable rig.
The boat rewards a crew that keeps her flat and punishes sloppy heel with a tendency to broach, although she recovers quickly and planes in stronger breeze. Below decks, she is as sparse as a day boat, and the deck-gear layout lacks logic. Even so, the original concept—a cheap, safe and exciting keelboat for competitive racing—remains intact.
Pros
- Lead bulb keel provides substantial righting moment, while the Vinylester solid hull is expected to be tough and durable
- Substantial mainsail and two-jib setup provide power in light air and upwind
- Planes downwind in stronger breeze, with rapid pace reported
- Sails with four or five ordinary crew without frightening or boring them
Cons
- Must be sailed flat and tends toward a broach when heeled unless the crew constantly eases the sheets
- Deck fittings and mast-base controls are laid out illogically and can be difficult to operate from the rail
- No real accommodation; below-deck space is cramped and difficult to access
- The open-topped spinnaker bin allows the spinnaker to spill over the side during takedowns
