Design Brief & Intent
The Friendship 21 was designed to inject high-performance agility into the pocket-cruising market, offering a more athletic and modern alternative to the builder's older, heavier Friendship 23. De Ridder’s objective was to create a boat capable of navigating the shallow tidal flats of the Wadden Sea and European inland lakes while maintaining enough structural integrity to handle demanding coastal chop. This dual-purpose role as a flat-water explorer and a spirited coastal racer set it apart from typical mass-produced competitors of the era, which were often relegated solely to protected waters.
The interior design maximizes every inch of the boat’s compact hull. While the cabin headroom is restricted to just 4.69 feet, preventing standing headroom, the layout manages to comfortably sleep four adults using a traditional V-berth forward and two flanking settee berths in the main saloon. True to the Dutch pedigree, the interior joinery and woodwork are of a high standard, with robust fiberglass moldings accented by warm teak trimming. It is a cozy, functional space, ideally suited for weekend cruising or short-duration family trips, trading cavernous standing volume for exceptional on-the-water performance.
Variations & Configurations
To accommodate various sailing environments, the Friendship 21 was offered in two distinct underwater profiles: a fixed fin keel and a highly popular lifting keel system. The standard fixed fin keel carries a draft of 3.61 feet, optimizing windward tracking, stiffness, and ultimate stability. In contrast, the lifting keel version utilizes a swinging centerboard that reduces the minimum draft to an impressive 1.0 foot, allowing the boat to navigate extremely shallow channels, dry out on sandy tidal flats, and float easily onto a road trailer for effortless highway transport.
Rigged as a 7/8 fractional sloop, the sail plan is easy to manage short-handed. Unlike the masthead sloops of the era that relied on large, cumbersome genoas, the fractional rig relies on an easily adjustable backstay to control mast bend, making it highly tuneable and satisfying for sailors who enjoy active trimming. Propulsion is designed around an outboard motor mounted on a transom bracket, keeping weight out of the ends of the boat and maximizing interior storage space.
Sailing Performance & Handling
The design elements of the Friendship 21 translate into a boat that feels incredibly communicative and energetic at the helm. Weighing in at a featherlight 2,182 pounds, the hull boasts a displacement-to-length ratio of 152.85, categorizing it as a light-displacement vessel. This low displacement enables the boat to accelerate almost instantly in light puffs and easily surf downwind in a blow. This agility is supercharged by a sail area-to-displacement ratio of 21.6, showcasing an exceptionally powerful sail plan for a boat of this scale. Under sail, the vessel is often described as feeling like a large dinghy—rapidly responding to minor rudder inputs and transferring wind shifts directly to the helmsman's hand.
This racing-style agility does demand active crew participation. With a capsize screening ratio of 2.53 and a comfort ratio of 10.43, the Friendship 21 is a tender boat that heels quickly when pressed. It is highly sensitive to crew weight placement and will feel lively and motion-heavy in a short, steep chop. To maintain control and avoid excessive heel, the crew must be prepared to reef the main early or swap down to a smaller jib as the wind rises above moderate levels. For experienced sailors, this lively behavior is a joy, but it requires more attention than a heavy, sluggish cruiser.
Known Issues & Triage
Given the age of the fleet, potential owners should inspect several known structural and mechanical areas. The most prevalent maintenance challenge involves the acrylic cabin windows. Because the lightweight fiberglass cabin top and the rigid acrylic window panels expand and contract at different rates during temperature swings, the original seals frequently degrade, leading to cabin leaks. Standard triage involves removing the windows, re-tapping the stripped mounting screw holes with epoxy resin to restore their threads, and re-bedding the panels using a highly elastic marine sealant specifically rated for acrylic-to-fiberglass interfaces.
Another area requiring attention is the outboard motor bracket and transom mount. Because the outboard is positioned low on the transom to ensure proper propeller depth, the motor’s powerhead is vulnerable to being dunked when the boat heels sharply under sail. Experienced owners recommend utilizing a sliding track or pivoting bracket that allows the motor to be raised completely clear of the water when under sail. Furthermore, the deck hardware—specifically the genoa tracks, stanchion bases, and handrails—should be checked for moisture ingress to ensure water has not compromised the deck core.
Modernization & Upgrades
The lightweight, outboard-powered nature of the Friendship 21 makes it an ideal platform for modern, clean refits. A growing number of owners are replacing older, noisy gasoline outboard motors with clean electric propulsion systems, such as Torqeedo or ePropulsion units. This upgrade is highly viable because the boat’s low displacement requires minimal thrust to reach hull speed, and the removal of gasoline cans frees up valuable storage space and eliminates chemical odors from the cabin.
To support electric propulsion and simple cabin electronics, modern refits often include retrofitting the electrical system with a compact lithium iron phosphate (LiFePO4) battery bank. Because these batteries offer exceptional energy density, they provide ample power for weekend cruising without adding the performance-killing weight of traditional lead-acid batteries. Upward-looking owners also frequently optimize their sail plan by replacing old, blown-out genoas with modern, high-aspect ratio dacron or laminate jibs, which improve the boat's pointing ability and reduce heel in gusty inland sailing conditions.
The Verdict
The Friendship 21 is a rare and rewarding pocket cruiser that punches far above its weight class in terms of sailing performance and design intelligence. It is not a boat designed for heavy offshore voyaging or long-term liveaboard comfort, but rather a fast, elegant, and highly responsive trailer-sailer that brings genuine joy to day-sailing and coastal exploration. For those who value pedigree, quality Dutch engineering, and dinghy-like handling in a pocket-cruiser format, this Koos de Ridder classic remains a brilliant option on the used market.
Pros
- Exceptionally fast and nimble performance in light to moderate winds.
- Easily trailerable, expanding cruising horizons and reducing seasonal slip fees.
- Highly versatile lifting keel option allows for shallow-water exploration.
- Superior Dutch build quality and clean joinery compared to typical production trailer-sailers.
- Simplistic systems make it an incredibly cost-effective boat to maintain and refit.
Cons
- Relatively tender hull shape requires active sail management and early reefing in heavier air.
- Low headroom of under five feet limits comfort for extended stays inside the cabin.
- Transom-mounted outboard is prone to powerhead submersion when heeling sharply.
- High scarcity on the brokerage market, particularly outside of Northern Europe.
