10' 6" Surf Lifesaving race prone paddle board self build - help and advice needed

General Discussion
1

Hi

Just after any advice for a self build project, 10’ 6" SLS race prone paddle board.

My kids have got into surf lifesaving, and are getting more adventurous (longer paddles out into the depths).

This has meant that paddling a surfboard with them is no longer an option, can’t keep up, shortboards are a pig to paddle a few kilometres at any kind of speed.

I’ve been looking into to making a 10’ 6” SLS style prone race board. Played with a few at SLS club.

US blanks have been super helpful, and I’ve found someone locally that can cut up to that length from a shape 3d file that I’ve put together (with some help from warehouse files).

The thing I have no clue on is construction. Fairly familiar with surfboard laminations and have made a few that have turned out well, but still very much a novice and can count my builds on one hand!

In my head I was thinking either:

  1. Carbon option
    2 x 6 Oz Top
    1 or 2 x 6 Oz Bottom
    Extra patches for knee area to avoid pressure dings, 1 or 2 extra layers.
    Epoxy resin
    Might try out vacuum bagging on this.
    I’ve also seen a few people add some 4 Oz eglass over this to help with impact and to stop the carbon being sanded into.

  2. SGlass option
    2 or 3 x 6 Oz Top
    2 x 6 Oz Bottom
    Extra patches for knee area
    Carbon tape stringer to keep it stiff, potentially 2 strips of 50mm top and bottom.
    Epoxy resin

Blank
1.5 EPS (or US Blanks have an option of #2 EPs - but not sure if that would make it too heavy).

I have a tendency to over build, and a few of the short boards I’ve built have been built proof, but a little heavy. Want to make this somewhere near the 7.6kg mark that the SLS guidelines suggest.

Cut
Looking at 10’ 6” length, 20.5” wide, about 6” at thinnest point.
Does that look right? Wanted something similar to the Kracka boards - They seem to work really well.

Does any one have any experience or pointers on what I should use?

Would 1.5 EPS need HD Foam inserts for the fin box and handle inserts?
Handle inserts, have seen pre and post lam versions, but if anyone can suggest what works well.

Fin, was thinking 10.5” futures pre lam or Fins unlimited 10.5" post lam.

EPS venting, was thinking of using a gortex vent somewhere.

Many thanks for your time and experience, any advice or suggestions are very much welcomed and appreciated… This will be a step up in complexity for me, and I just want to make sure I’m headed in the right direction.

2

What is volume ? 1.5 eps would be too heavy. prone paddle i see were 1 lb and not as much fiber, light and fragile. For this size less than 8kg is light. Carbon and light eps. For that, if you have a good technique you wouldn’t use vaccum bag.

3

Hi lemat

Thanks, it’s about 150 ltr at the moment. I can up this fairly easily.
I think one of the files I started out on was 170ish (but was 54-56cm wide - wasn’t sure if that was getting too wide to paddle comfortably).
I think US blanks had 1lb, I can ask. Guessing that would need HD foam inserts.

So go back to 6oz top and bottom with knee patches for carbon. Maybe slim down the S2 option to 2x 6 top and 1x 6 bottom (with knee patches).

Just checked, can get 1lb.
No vacuum bag - great, one less thing for me to mess up :slight_smile:
Technique is o.k. might not be hitting the ratios, but I’ll probably not notice as I’m not racing, just chasing the kids around.
I guess if the rails wrap enough, should be able to just do I layer top and bottom (+ knee patches). Will that need a carbon stinger, or is that just redundant when laminating with carbon.

Thanks for your comments…

4

Ok i think it’s more volume…
Well for simplicity/efficacity ratio i would go with 1.25 foam (19/20 kg/m3 in metric) if you can do sandwich i would use it on standing place with glass or carbon under).
For your use glass or carbon depend how much money you want to pay to reduce weight.
Empiric ratio is twice less carbon than glass by weight. Your board will be thick so i think you probably don’t need carbon strip stringers but well cover rails with all fiber layers. If you don’t take waves may be 6oz carbon over and under with sandwich standing area is enough. If you want a bit more of dings strengh add some glass in the mix.
Vaccum is good for optimal weight/tensil strengh but boards skins work mostly in bending and break because of shear buckling under compression forces frombending stress. Here optimal fiber/resin ratio isn’t the same. Plus skin need to be waterproof so more resin… Here vaccum must only be use to conform fiber to shape without compress fiber. There is other simple way to go for that.

5

Thanks Lemat