Hi, I was 120kg when I got back into surfing, now 110 so I think I can add value to this thread. I have two boards I mainly surf, a 10ft 6, custom and a Ben Aipa 10ft2 Bigboy stinger. The 10ft6 is Pu and 25 inches wide, this makes it extremely stable when I get to my feet. The Aipa is only 23.375 inches wide but 4.5 inches thick, at my size back then with a big belly, it made the board very tippy/unstable when i paddled it. I wish Ben Aipa had made his template another 0.625 inches wider it would of been perfect for my size back then, mind you Mr Aipa is not a big guy, so he probably designed it with himself in mind. I wouldn’t recommend Bigboy Stinger dimensions for a 120 kg learners board for that reason. Back to my custom board, it has a full nose and an almost gun like tail, well pin tail maybe. When I ordered it I was taken with a particular Roger Hall(Kiwi Shaper, check out his website) design that had a full nose and thinned down in the tail, named after a HD model, the electraglide. That was a design mistake, if you are in the 120kg division and getting back into surfing you don’t need a big gun look alike tail, although it does turn easily and noseride. BUT it is hard work trying to catch a wave, on reflection I wish I had orderd a full round tail or even a Bob Simmons look alike tail. Why a full tail? Big guys, on a scale, have heavy legs and heavy hips so width in the tail is to both give sufficient flotation and to get the board up and planning on the face of the wave, especially while trying to catch one. You mention that you don’t need to worry about performance so you don’t need to get all technical with tail rocker being x inches etc, however you do need nose rocker, my mate who has ridden the Aipa hates it as, in his opinion, it has no nose rocker and he is always pearling when he paddles for a wave.
Summary:
Blank: Get one as long as possible, well maybe even a sup blank, avoid a 10f6inch - 11ft blank with too much obvious rocker, you will end up with a bananna board. The object is to get some nose rocker and not too much tail rocker, this will make it a dream to paddle and appreciated by your mate. He can sell it for a more advanced model when he is ready and be able to say that it is the perfect, learner/intermediate/noserider board. Shape it so the paddler can be as far forward as possible when paddling, without making it dead flat, if you manage to achieve this, share how you did it please.
Length:10 ft to 10ft 6, this should be enough, but there is no reason not to push it out to 11ft especially if you can keep the overall rocker down,
Width: minimum of 24 inches, go to 24 and a half, or 25, especially if he is tall, it is hard to sit with your legs spread that wide, but achieveable. The Munoz 12fter is 26 inches wide I think, never ridden one but wouldn’t mind trying, the 26 inch width would be a challenge to sit out the back on and maybe ruin the overall out the back experience. However, as your mate paddles twice, springs to his feet, or probably takes the two step lumber, the width of the board will provide him a stable platform that will ensure that he is up and away in a far shorter time than on a regular non-custom
Thickness: 3 and half inches is good, three inches will be fine if you have the width i.e dont try and chase the maximum thickness you can by just skinning a blank if it has bananna type rocker.
Nose: 19 inch nose will allow him good nose time when he is ready and able
Tail: I don’t have recommended tail dimensions, just draw the tail down slowly to a biggish round tail, or even a vee bottom square tail, the more tail width and bouyancy the better, remember to look at your mates body build and take that into account. 160-168 pounds is probably the average surfers weight, consider that your mate has an extra 100 pounds, almost another person, well say the equivalency of a tandem team. When he is good, Reverb’s recommendations might hold true, but not at the beginners level.
Weight: If you are building with PU, weight isn’t really an issue, it is going to be heavy, double six on top plus a knee pad ( he may be able to kneel paddle this in time) and six oz on bottom. At 120kg he will have the strength to lift it and paddle it. If you are building an epoxy, I would stick to these dimensions as well, it should be a lot lighter obviously. Again not life threatening at your mates level. PU probably better to noseride at his weight, but this is debatable.
Rails: Not being a shaper please consider this advice from a consumers perspective. The prime focus for this board should be to make it as easy to paddle as possible. The rails should be designed to give the board maximum float and minimum drag when paddling. If you shape the last third of the board with turned down hard rails to make it a higher performing board, it will, in my opinion, slow the board down when paddling, as the board is floating IN the water at the back, rather than taking advantage of the bouyancy available and floating on TOP of the water. To achieve this you need to design rails at the back that will allow the board to bottom turn and cutback as well as provide maximum float/bouyancy. Being a big guy he will be able to throw the thing around once he gets on his feet, just because of his size , so you don’t have to provide him with extra performance details that a smaller person needs. Look seriously at rail design, this is the make or break of the board. The rails do need to be turned down at the back but exactly how, for a 120kg learner should be a source of debate. Maybe the SUP guys can jump in here.
Fin: Big guys only need a big single fin.
Hope this helps, looking forward to see what design decisions you make as it could be the board I am still looking for.
MrT