The effect of tail thickness on float and planing

General Discussion
1

This past week I’ve been riding a swallow-tail longboard in 3-4’ low energy, NJ sloping waves with a bit of curl. I noticed that the water line is about where my ribs start during paddling. Here are the specs: 

8’2" x 22 x 3"

T@12"  = 14.0" wide, 2.0" thick

T@06"  = 10.5" wide, 1.2" thick

N@12"  = 15.5" wide, 1.6" thick

Me: 5’9" and 165 lbs wet

This is tons of foam for a guy my weight, but with the tail sunken it slows me down to paddle. My line of thinking is this: there are three “modes” of a surfboard: paddling on flat water, planing into a wave, and turning once youre up. If this board had more thickness in the tail it’d sink less, paddle flat easier, plane into a wave faster, but feel less sensitive in a turn. How do you resolve these sacrifices and do you have a rule of thumb for whats acceptable or not in this situation?

2

Hello; I put a bit more (on the middle part) of thickness at 1ft from tail and nose in most of my orders.

Regarding sensitive into turn: My approach is depending on your stance and position of rear foot then depending on the concept of the board (hot dogging surfinn or down the line, projection) I work hand on hand with the outline and rocker (plus side fins position and template)

I put more rocker in that area than many; even more under back foot if your stance is too low and you are a front foot surfer.

 

3

Tell me if I got this right. Redgarding “middle part”, you’re saying you add more foam overall to the nose and tail so it floats better. But then you compensate to make it turn a bit easier by adjusting tail rocker and profile, based off how it’ll be used?

4

No; I said that I let more thickness over the middle stringer at 1ft from nose and tail.

In my opinion that board that you have with 3 inches thickness near the middle and only that thickness at the other marks, is too tapered out. You need to check that foil.

 

5

How do you judge your surfing? Beginner, Intermediate, Pro?

Because if your tail sinks to much during paddling, the chances are, that you are just lying  too far back. No matter what shape a board has, to paddle efficiently, the board has to lie flat on the water, even if the tip is almost under water, the more you lie in the back, the more drag you have, and it is difficult to catch waves.

A 8’2" x 22 x 3" board has enough surface to plane and a volume of at least 55, if not 60litres. For an experienced surfer it is a paddling machine… Even with 165lbs it should float rather nicely, no matter how the tail is shaped.

I have a similar sized board, a clone of a CJ Nelson MIdlength Colapintail. These are the specs of the original:

8’3″ x 21 1/2″ x 2 3/4″ (55 L)

Width 12″ from nose: 17 11/16″

Width 12″ from tail:13 13/16

This board is smaller in width and thinner in the tail than yours, mine with just 8’’ length is my favourite board. I would rate myself beginner to intermediate…, this board performs perfectly for me and it is fun to paddle, you get lots of waves, definitely more than the shortboarders around you…

Check the video and see, what fun a midlength could be. This board turns on a dime…

https://cjnelsondesigns.com/surfboards/colapintail-midlength/

6

Im intermediate and ride six different boards and I should add that the reason im asking this question is to better understand tail thickness as I move forward and shape more boards. Regarding “the board has to lie flat on the water”, are you sure about that amigo? Maybe Im misunderstanding you, but when I look at any shortboard, the only time its laying flat on top of the water is when it’s planing or starting to because the slope of the wave has pushed the tail upwards. All other times its mostly underwater angled slightly up. While I understand your point of positioning on the board, I have six boards here that I ride, everything from a 9’0" to 6’2". Of course at the upper end the 9’0" lays flat on top of the water. I ride an 8’0 with big boxy rails and that lays flat on top of the water too. But this 8’2 Im referrring to does not. Anyway I think Reverb is right saying its because this board is heavily foiled. Jon Ashton shaped it and Im sure he had a reason to do it this way. I’ve been happy with it from day one, so much so that I tried calling him after I rode it in on a trip in El Salvador, it performed very well on long period overhead sets. But he wouldnt return my phone calls to chat. Either way, you’d have to sit with the nose nearly sinking in order for it to sit on the top of the water. 

7

If the tail is sinking on that size board, you’re definitely lying to far back. When you said “the nose would nearly be underwater”, that’s correct. It should be, on any board. 

8

Then I certainly have a lot more to learn than I thought. Thanks for explaining

EDIT: wait, this cant be right. for the past two years ive paddled with 1-2" of the nose tip out of the water. youre telling me that when you paddle a longboard, the tip is skimming the water line or beneath it? ive never once seen anyone do this

9

I have.

10

Since I’m only a poor surfer too, I can not give perfect advise, but check out some videos of Rob Case, he is a paddling technique teacher. I did one of his internet paddling courses and even without the chance to go on the water for month, my paddling improved noticably. Besides the physical techniques, the key to fast paddling is reducing drag, drag of the “vessel”, the board, drag of the body and drag withing the paddling motion. And the drag of the board is determined by its shape and how it lies on the water.

And if your body is just one inch behind the sweetspot your tail sinks to much, if your one inch in front the tip is going down. So exact positioning is crucial!

For me this is actually the ideal spot, weight slightly forward, because if you then  bring up your chest high, with a banana shaped back, the board levels or even starts sinking in the tail. This is the moment when you control your board with your belly. Depending on the wave you you are able to control the board, Just before the pop up, your weight may be as far in front as possible, to catch the wave perfectly, and you can perfectly adjust this with slight movements of your upper body. 

Paddling and getting the wave is one part, riding the other, here thickness and shape of the tail makes a big difference. I’m a front footed surfer and therefore I like thinner smaller tails, i.e. pintails, because the make it easier for me to sink the tail into the wave, when I want it, which is breaking, stalling, and of course turning. If you are more backlegged, the tail must not support sinking much, because you do it naturally

 

https://www.youtube.com/watch?v=GfDNTfk09ao  (Watch here to start with 1-2 inches above the water and the improving, sinking it to 0-1 inch…)

https://www.youtube.com/watch?v=5QrNvmR4qu0

https://www.youtube.com/watch?v=_5enGHbOiPU

I’m not paid byRob Case and I do not want to place an add for him, but I liked his approach and it definitely helped to improve my paddling. He may appear to scientifically, but that is a thing I like. If I understand the basic physics, I can work on the subject, without a proven backround I can not improve, which is may an influence of past engineer studies. When I started surfing after one hour, I had severe problems with my shoulders, I could not even raise my arms after surf and I paddled rather slow. Now I’m far away from beeing a perfect paddler, not to mention a good surfer, but I stay outside much longer, paddle faster and feel no more pains, I’m just exhausted after surf. I started surfing late, at the age of 40, being able only to surf on vacation, now I’m 57, catching  more waves than ever before, but still on beginners/intermediate level, headhigh is my boundary… 

 

 

11

Man was I wrong, what an eye opener! This means most of the folks I surf with, myself included, have been wasting energy and catching less waves withou tknowing it. Amazing really, considering the folks I took lessons from early on didnt get into the importance of this. Anyway, thank you all for getting me back to basics.