Low Volume Longboard SUP (dreaming one up)

[surfafrica]

I chatted with the shaper today after sending him a picture of me standing on my 87 L board.  He thinks if I'm game, I should try 84 L with the new longboard.  Some interesting insight from him for those interested:

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A board with more surface area will provide more stability than a smaller board at equal volume, this is true. But boards with more surface area require more volume to have good glide (imagine paddling a 14’ race board that’s so submerged that water is coming over the deck)--as the board’s volume decreases and it sinks lower in the water, you have to push more of it’s surface area through the water.

My ideal ratio is 1.1 (including 13 lbs for board, paddle, fins, etc).  I’ve experimented with a lot more and a lot less and that’s what I like. But everyone is different.

The only thing you left out is board weight (which is optional) but which we can include to be extra precise/thorough. Let’s see what we have:
   
Your weight w/wetsuit..... 155 lbs
+ board/fins/paddle/etc.... 15 lbs
................................. = 170 lbs (77 kg)

Current board = 87 L
Ratio = 87/77 = 1.13

Have you double checked how much your wetsuit weighs? I used to weigh mine right after getting out of the water post-surf and it was like 3 lbs (that smoothskin suit soaked almost no water). Looking at how submerged/floating the 87 L board is in your attached photo, I’d guesstimate that you’re running at more than 1.13.  To answer your question, I think we can drop the volume to 84 L no problem. It’ll help with your progression, and the board will still have good glide.

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If I reduce my wetsuit to 5 lbs, I'd get:

My weight w/wetsuit......... 150 lbs
+ board/fins/paddle/etc...... 15 lbs
................................... = 165 lbs (74.8 kg)

Current board = 87 L (7'5 x 26)
Ratio = 87/74.8 = 1.16

New longboard = 84 L (8'10 x 26.5)
Ratio = 84/74.8 = 1.12

My 87 L board barely has water coming over the deck. So I think I'd like to give 84 L a try - 8'10 x 26.5, 84 L.  I want to push myself with this one.

[anonsurfer]

I think you should go with the lower volume option.  As you stated: "Every time I've dropped down a step in volume, I've loved the result."  Your 87L floats you very well, I don't think you'd have too much problem adjusting to an 84L board.

Note that as you get lower in L/KG ratio small differences in volume (and width) start to become more noticeable.  For example I can stand on my 6-6 x 28 x 87L for long periods without the paddle in the water.  It is super stable.  My 6-10 x 27 x 84L takes a bit more work even though it is only 3L less.   For reference I am 160lb with wetsuit.

[surfafrica]

anon, after this longboard project, I think my next one will be a performance shortboard SUP--I've never tried one.  I think my NB has been a good gateway drug.  If I'm every down at Thor's Hammer, I'm going to touch base with you with offers of burgers and beer.  I'd die to try some of your boards.  Not many people out there using the size ratios you are using. I'd probably start my shortboard project thinking in the 7'4 x 27, 80 L range, but I'm so curious on how going shorter and thicker like your sub-7s would feel.

[supuk]

most of your stability will come from the outline and length and width. I do all my boards at the same volume which is about 1.09 X Longboards with a large surface area give a lot of extra stability don't worry to much about dropping the volume

[anonsurfer]

If I'm every down at Thor's Hammer, I'm going to touch base with you with offers of burgers and beer.  I'd die to try some of your boards. 

You are welcome to try any of my boards.  Definitely let me know if you are in south OC, California.

but I'm so curious on how going shorter and thicker like your sub-7s would feel.

My preference is shorter lengths with a little extra thickness (within reason).  I find that a shorter board is much more maneuverable than an equivalent volume longer, thinner board.  A little extra foam between your feet it is a lot easier to throw around than having that same foam 3ft+ out in front of you.     

[surfafrica]

I was just reading through a thread by @supsurf-tw and it sparked a question I have about what to choose for a 2+1 setup for this board.

@supsurf-tw - http://www.standupzone.com/forum/index.php/topic,30430.msg332853.html#msg332853

Sorry for the repeat post, but thought I might get some good insight from the folks subscribed to this thread.

I've settled on 8'10 x 26.5, 84 L for this longboard SUP, and I'm 145 lbs. I usually ride quads, but am looking to ride this new one as a 2+1 (although I'm getting quad + 1 boxes put in). I was thinking of going with a 6"-7" center fin but am unsure how to approach the sidebites.  Should I go for a similar size as my front quads?  Or do I go for a smaller set of sidebites on a 2+1? 

Here's the set I am eyeing - https://3dfins.com/collections/sup/products/fastlight-surfsup-2-1-medium-fcs-compat

Center: 6.25"
Sides: 4.56" (high) x 4.34" (base)

But, with my weight should I be looking for something more like 3.5" sides?

My gut is that with the added width of a SUP (and more foam in general vs a prone longboard), having a little extra fin is the way to go. Am I on the right track?

[surfafrica]

...or smaller sidebites like this - http://www.trueames.com/collections/side-bites-1/products/side-bite-3-7-futures-compatible

[Subber]

I'd start with 3.5" (GL) sidebites.

Smaller will probably be better if you want more speed.

Larger will probably slow you down.

[surfshaver]

If it's a high performance longboard style, not a nose rider, then don't go bigger than 6" for the center fin and 3.5" for the sidebites.  I have a prone longboard with a similar setup, and it's 22 inches wide.  At 26.5 inches wide for the board the tail won't be too wide if it's a typically pulled in performance LB shape.

If anything, go bigger on the side fins and smaller in the middle fin. 

PS  -- thanks for the input on my new Popdart.  Going to pick it up this week!

[surfafrica]

Thanks guys.  Here's what I'm going to go with:

6.25" Center
3.57" Sides

[surfafrica]

Just got my first pic of the new LB.  I'm psyched to see the rails.

Kronos Longboard SUP
8'10 x 26.5, 84 L
12.75 lbs

[surfcowboy]

This looks great!

I missed this thread for a while so I'll post up.

Totally agree on the lower volume I'm interested in the lower limits. SupUK has been all over this for years.

Linter, on the 50/50 rails I think it's more the whole bottom that I'm really thinking of. 50/50 with a flat bottom and good volume placement is probably fine, as you say. I'm actually a bit off the deep end thinking of a true round bottom soft rail LB where you see the bottom almost as a convex saucer where the rocker and a rounded bottom flow right into the rail. It probably would be impossible to paddle but I'm really chasing that Wingnut style step back turn.

For now, I'll stay on the prone longboards for a bit and see where that takes me.

Love this board, can't wait to see it in the water.

[anonsurfer]

Just got my first pic of the new LB.  I'm psyched to see the rails.

Kronos Longboard SUP
8'10 x 26.5, 84 L
12.75 lbs

Looks great.  What was your glassing schedule?

[surfafrica]

It’s 6/6 on top and 6 on the bottom with an aramid vector net/carbon strip layer.  Vacuum bagged.

[SlatchJim]

Any ride reports yet?