By eliminating the cabin trunk, Sparkman & Stephens maximized the cockpit footprint, creating a day sailer that prioritized group ergonomics over interior overnight comfort. Unlike competing small day sailers of its era, such as the Rhodes 19 or O'Day Mariner, which relied heavily on crew weight and hull form for stability, the Knockabout 24 utilized a deep, high-aspect cast-iron fin keel to deliver immense righting moment. The result was an exceptionally robust, un-capsizable vessel capable of carrying up to five students and an instructor in comfort, establishing a blueprint for sailing education that remains active over six decades later.
Variations & Configurations
While sharing the same Sparkman & Stephens Design 1701 hull and underwater profile, the platform was offered in several distinct deck and interior configurations to suit different niches.
The original Rainbow 24 configuration featured a low-profile cuddy cabin forward, enclosing a small V-berth for gear storage or emergency shelter. The Knockabout 24 variant was stripped of this forward cabin deck to create a completely open, high-walled cockpit spanning nearly two-thirds of the boat's length. This configuration maximized legroom and allowed instructors unobstructed view and access to all controls.
For sailors seeking a pocket cruiser, Tidewater Boats introduced the Weekender 24 (Design 1701-C1). This model featured a raised coach roof that provided 50 inches of headroom, sleeping quarters for four adults on a double V-berth and two straight settees, a slide-out galley with a sink and icebox, and a marine head positioned beneath the forward berths. A slightly longer cruising iteration, known as the Chesapeake 25, was also produced for multi-day school flotillas. Across all variations, the sail plan remained a masthead sloop rig controlled via a tiller and an internally-mounted, balanced spade rudder.
Sailing Performance & Handling
The sailing characteristics of the Knockabout 24 are defined by its narrow beam, light displacement, and heavily ballasted keel. Sporting an athletic sail area-to-displacement ratio of 19.95, the boat is surprisingly lively and responsive. It catches light summer breezes easily, accelerating out of tacks without the sluggishness common in heavier pocket cruisers. This responsiveness is a critical asset for a training vessel, as it provides immediate helm feedback, allowing beginners to easily feel the physical consequences of sail trim adjustments.
Its physical behavior in a seaway is governed by a ballast-to-displacement ratio of 49.78%. Carrying nearly half of its 2,250-pound displacement in a 1,120-pound cast-iron fin keel, the Knockabout 24 is exceptionally stiff. S&S deliberately increased the ballast weight after the very first production hulls exhibited slight initial tenderness. Under sail, the boat will heel readily to a comfortable angle, but as the wind increases, it rapidly meets its primary stability limit.
The displacement-to-length ratio of 195.69 positions the Knockabout 24 as a moderate displacement design. With a slim 6.25-foot beam, the hull presents a narrow entry that slices cleanly through chop rather than pounding over it. This "needle" profile delivers excellent directional tracking, though the motion is active, as indicated by its comfort ratio of 15.65. The capsize screening ratio of 1.91 sits safely below the traditional ocean-racing limit of 2.0, underscoring the hull's high ultimate stability and resistance to roll-overs. Steering is remarkably direct via the balanced spade rudder, though helmsmen must maintain a firm grip in gusty conditions due to the high-aspect sail plan.
Market Snapshot & Economics
The Knockabout 24 was manufactured from 1962 through approximately 1977. Including all of the deck variants, it is estimated that Tidewater Boats built roughly 500 hulls. Today, they represent a highly affordable, classic niche on the brokerage market. Because they do not command a premium, they trade at a deep value, often appealing to purists, day-sailing enthusiasts, and budget-conscious buyers looking for Sparkman & Stephens pedigree in a small package.
The refit economics of a Knockabout 24 are highly favorable due to the absolute simplicity of its systems. The boat does not carry complex inboard engines, pressurized plumbing, or intricate DC electrical grids. Auxiliary power is typically provided by a 3 to 6 horsepower long-shaft outboard mounted on a transom bracket. Consequently, the typical financial outlays for a restoration are limited to cosmetic hull work, standing rigging replacement, and sail replacement. Buyers should, however, evaluate the vessel carefully, as the cost of a new set of sails and a complete rigging overhaul can easily exceed the market value of the boat itself.
Technical Triage & Known Issues
Decades of service, particularly in harsh school and rental environments, have highlighted several areas that require technical triage:
- Keel-to-Hull Joint and Cast-Iron Corrosion: The cast-iron fin keel is bolted to a shallow sump. Over time, the polyester fairing compound at the keel-hull joint cracks, allowing seawater to come into contact with the iron. This results in rust bleeding, scale formation, and cosmetic blistering. Restoring this area requires grinding the keel down to bare metal, treating it with a phosphoric acid rust converter, re-fairing with structural epoxy compound, and sealing it with several coats of epoxy barrier coat before applying bottom paint.
- Spade Rudder Delamination: The balanced spade rudder features a bronze or stainless steel shaft inside a foam-cored fiberglass foil shell 2. Water frequently migrates down the rudder post over time, rotting the core and leading to skin delamination. If the rudder feels heavy, sounds hollow, or weeps rusty water when hauled out, it must be split open. The compromised core should be dug out, internal reinforcement tabs inspected or re-welded to the post, and the foil re-poured with high-density epoxy foam before being wrapped in new biaxial fiberglass.
- Deck and Cockpit Sole Softness: While the hull itself is a solid, heavy-duty fiberglass layup, the decks and cockpit soles on some hulls utilized plywood or balsa cores. Inspect the areas around chainplates, cleat backings, and the cockpit floor for flexing. Soft spots indicate water intrusion, requiring local core replacement by drilling, scraping out rotten wood, and back-filling with epoxy, or cutting away the fiberglass skin to lay down new marine plywood.
Modernization & Upgrades
Many Knockabout 24 owners have successfully modernized these pocket classics to enhance single-handed ease of use and environmental efficiency.
- Electric Propulsion Conversions: The Knockabout is an ideal candidate for electric outboards (such as a 3 kW Torqeedo or ePropulsion unit). Because the hull is highly efficient and requires very little thrust to achieve its 5.57-knot hull speed, a lightweight electric outboard paired with a small lithium-iron-phosphate (LiFePO4) battery pack provides ample range for harbor maneuvering. This eliminates the weight, noise, and maintenance of traditional gas outboards.
- Rigging and Deck Layout Upgrades: To simplify single-handed sailing, veteran owners often install a modern mid-boom sheet traveler, lead halyards aft to the cockpit, and install cam cleats on the coamings. Replacing old wooden cockpit floorboards with low-maintenance synthetic marine foam (such as SeaDek) provides durable traction and modernizes the cockpit aesthetics without sacrificing the boat's classic appeal.
The Verdict
The S&S Knockabout 24 is a historically significant, exceptionally stable, and highly responsive day sailer that represents the golden era of fiberglass design. For sailors seeking a pure, elemental sailing experience backed by the safety of an un-capsizable hull, this Sparkman & Stephens classic remains a compelling and highly economical choice.
Pros
- Exceptional Stability: The high ballast-to-displacement ratio makes the boat virtually impossible to capsize.
- Spacious Cockpit: The elimination of the forward cabin provides vast legroom and working space for day sailing.
- Responsive Performance: An athletic sail plan ensures the boat is highly rewarding and communicative at the helm.
- Structural Durability: Built during the era of thick, over-engineered fiberglass layups.
- Low Maintenance: Minimal onboard systems keep operational costs and refit times incredibly low.
Cons
- Minimal Accommodations: Lacks any true overnight cabin or cruising amenities in the Knockabout configuration.
- Active Motion: The narrow beam and light displacement result in a lively ride that transmits wave action directly.
- Keel Maintenance: Cast-iron keels require diligent monitoring and periodic re-fairing to prevent corrosion.
- Age-Related Wear: Most surviving examples require cosmetic gelcoat restoration and core triage.
