illustration of the campbell brothers and their bonzer surfboard design, by clara jonas

The History of Surfboard Design: The Campbell Brothers and The Bonzer

Words by Kim Feldmann & images by Clara Jonas (illustration), Nathan Fletcher (blueprint), Callum Morse (photography)

Created in 1970 and perfected over the next couple of years by Californian brothers Duncan and Malcolm Campbell, the Bonzer is considered to be the first standardised surfboard model to herald the tri-fin setup. Despite embodying innovative features (namely the tri-fin arrangement and the use of double concave) and stretching the range of performance in various wave types and sizes, the Bonzer’s popularity was short-lived and its influence in the history of surfboard design often undervalued. Overshadowed or not, the concepts introduced by the Campbell brothers served as foundations for the birth of the iconic Thruster in the following decade, whilst also planting another “seed of radicality” in the development of high-performance surfing.

The Historical Context

After Dick Brewer’s Mini Gun set the pace for the Shortboard Revolution in the late 60s, the tendency at the turn of the decade remained, for the most part, to pursue high-performance wave-riding through experimental board-making, with backyard shaping (as opposed to mass production manufacturing) continuing to drive design innovations.
By 1970, World Tour surfers were riding boards as short as six-foot, most of which still used a one-fin setup. As shortboards became an established category and longboards a somewhat niche market, refinements were now less associated with the size of boards and more with their design details. Noticing room for performance improvements and aiming to create an all-round craft, brothers Malcolm and Duncan Campbell, devotees of all-things-shortboard, began shaping even smaller boards (5’4” to 6’0”), eventually turning their focus to fin setup and bottom contours, which led to the creation of the Bonzer model.
Although the concept emerged at the end of 1970, it was only by 1972 that all key features – most notably the single-to-double concave and fin layout – were consolidated into the standard Bonzer design, which was licensed to Bing Surfboards in California and disseminated from then onwards. Despite being vouched for by many key surfers of the time, the Bonzer didn’t gain enough momentum to reach out to a wider audience and subsequently lost the spotlight just a few years after its birth.

Why Was This Development Necessary?

With the rapid break-out of the Shortboard Revolution, the majority of surfers of the late 60s realised that riding shorter craft opened up a whole new world. But these boards still had limitations, in particular related to the fact that most designs at the time were single fins, that wasted a lot of energy through turns and often fell short in terms of control and speed – even more so in bigger surf. Unwilling to reconsider the length of their surfboards yet thirsty to have an all-around board that would respond more readily to the zippier kind of surfing that began to develop, a solution was found by focusing on bottom design, with the idea of a triangular fin setup (a central fin placed a few inches back from two keel-like side fins) and the use of double concave providing the desired versatility without compromising length.

Who Was Involved?

Credited by Simon Anderson himself as being the forerunners of tri-fin boards, brothers Malcolm and Duncan Campbell were part of the second generation of Shortboard Revolution surfer-shapers. Born in 1952 (Malcolm) and 1955 (Duncan) in Santa Monica, California, the brothers took up surfing in 1965, moving to Oxnard, California a year later. They began making surfboards as teenagers, partially encouraged by their father, who also partook in the brainstorming process of the three-fin setup and suggested the name “Bonzer” for the new model the brothers gave birth to only two years later, aged 18 and 15, respectively.
Ahead of their time in terms of board-making, their outright pursuit for radical surfing and progressive approach to design was contrasted by their modest personality which, contrary to many exuberant characters in the world of surfing at the time, might have influenced the dissemination of their design innovations, but never really affected their resolve. After shaping the first Bonzer in 1970 and refining the model until its first official appearance in 72, they continued to explore the concept, coming up with a five-fin version in 82. Later, Duncan opened a cafe in the North Shore, Hawaii, whilst Malcolm carried on shaping in California.

Design Details

Template-wise, the Bonzer doesn’t strike as being overly experimental. At first, its idiosyncratic feature was its three-fin arrangement: two keel-shaped, shallow (~2 ¾”), long-base (~9 ½”) side fins pointed almost directly to the nose, placed roughly 1 ½ inches from the rails and 11 inches from the tail, just ahead of the centre fin, which was 6 ½ – 8 inches tall. This setup, particularly the placement and depth of the side fins, optimised the use of energy provided by water flowing through the tail of the board. On the one hand, it allowed the fin on the external rail to easily enter and exit the water during turns, facilitating rail-to-rail movement, whilst the internal fin, laying almost vertically against the water’s surface, supported the central fin with a bit more lateral resistance, thus providing more stability.
Later refinements, mostly directed at enhancing speed through flat spots and delivering more drive out of turns, caused the bottom contour of the Bonzer to change from the standard flat bottom of the day to a radical and deep single-to-double concave. The parallel double concave, hewn towards the tail area, was designed to work together with the fins: they created a complementary set of channels that, due to the tendency water has to adhere to curved surfaces, decreased resistance around the fins and redirected the water that flows across the bottom through the tail slingshot-like, thus diminishing the loss of energy and propelling the board during and after turns. Especially when riding on their back foot, surfers could now draw wider as well as sharper arcs and hold their line while performing more radical turns in larger surf.


Avg MinimumAvg Maximum


Nose12”12 1/2”
Midpoint19 1/4”21 ½ ”
Thickness2 ½”3”