I have been working out the design for a Bonzer type board and am about to make some templates, but there are still some questions concerning the shape. (I’ve been mind shaping it for a bit now)(keep in mind, I am looking at making a 5 fin)
So Bonzers have fairly deep double concaves running out the back of the board, somewhere around 3/8" or so. (modern ones seem subtler on the concaves) The ones that have glass-on side runners seem to all have subtle concaves running through the side runners; maybe 1/4" or so? Whereas the ones using fin boxes seem to be flat through the side runners.
From some of the pictures I have seen on the net, some seem to have some vee in the tail as well. ?
What about for the front part of the board? Is there a single concave that runs through it? How far back does it go?
I am planning on laying up my own set of fiberglass side runners, how thick are they? They do seem to be thinner than the normal 1/4" fin thickness. Would 1/8" be too thin?
Are the side runners single or double foiled? The foil also seem to be, ?short?, the foil doesn’t taper over the whole length of the fin, basically an even thickness over the baseline of the fin, with foiled edges?
What about the center fin box, is it a full sized 10" box, or a small one? I have a 7 1/2" box as well as a couple 10" in my shop right now, which one should I put in?
Thanks for any info. The shops that I do have around here pretty much stock the run of the mill boards, thrusters, fish and a few funboards so I have not been able to look at or fondle any bonzers in the flesh.
thats a boatload of questions that cal pretty quickly be found using the search thingy…so ill make my answers short
the bonzer bottom is a venturi shape, your single concave is under the front foot, and narrows towards the hip of the board, it is narrowest at the front fins where it blends into the double, and widens towards the tail following the fins’ angles…the concave is also deepest between all of the fins.
The fins are single foiled, they can be thin, their main purpose is to direct water flow, drive is also a big deal but since they arent tall, they dont need to be thick…1/8" full glass is alright. Youll want to foil them like a regular fin, thats a whole other subject.
all of the properly done 5-fin types have a narrow concave running between the side fins. IF you use lokbox on those fins, to do it right, you have to actually shape the box’ flanges to mimck the curves; not an easy task, but can be done with some grinder skills
a smaller finbox is fine, 10" ones are overkill…the leading edge of your center fin should overlap the trailing edges of your rear side fins by 1/4" or be even, somewhere in there you should find your sweet-spot, so make sure wherever you put your finbox will accomodate that placement.
hope that helps some, there is a ton more info all over this place, but there are some basics to start with!
I think the depth on the conccaves is much more subtle thanwhat you mention, at least on the Campbell brothers I saw. The single in the middle is almost imperceptible to the eye and hand. I didn’t have a straight edge when I checked them out, but I’d say definitely no more than an 1/8". The doubles are not that much deeper- 3/16" to a 1/4" max. The depths you mention sound more like the older bonzer3’s.
Hi Johan1, Here’s a Bing Bonzer style 5 fin using Proboxes. If you notice the pic to the far right,look at the center fin with the back cut out which allows the center fin to go future back. I would put at 10" box instead a 8". Mahalo,Larry
it might be wise to get physically acquainted with a campbell brothers bonzer. like the nihilist who refuses perugino’s color or bach’s music, speaking of single-to-double concaves and fin placement of a bonzer reduces its essense to the lego-building-block format of contemporary shapers. integrating the rails and rocker, the distribution of foam, and a proper template ought to be considered first. again, it might be wise to check out a REAL campbell brothers surfboard-- if you can’t buy one.
I recently made a 7’2" five fin bonzer - you can search for it by typing in ‘5 fin bonzer’ and selecting resources form the drop down box on the top right of swaylocks homepage.
Mines quite a big board as I’m a lover of volume…it’s an amazing board - loves steep walling waves - takes big drops with ease despite it’s flat rocker. I used the lokbox fins - didn’t have the side concaves running between the fins - just deep concaves upto about a third the way up the board - I also used a beveled rail off the stinger…and it seems to work really well - I would recomend the long center box - just gives you a bit more to play with when positioning the fin - I’ve ended up with mine slid a bit more forward than the usual bonzer position and it’s loosened it up a treat…good luck!
