Adding tail rocker/kick to an existing HP longboard?


I have a relatively thick 9’ HP longboard that has plenty of nose rocker (5,5") and a narrow (13,5") tail. The tail rocker is 3,3". The board works rather well in all conditions, but starts really shining in strong waves and shoulderhigh+. In smaller waves I miss my McTavish Original’s accelerating tail rocker swoop that gave a “carving feel” and did not stall if i stepped on the fins to make really tight turns.

What I had in mind was sanding the bottom open from sidefins backwards  and reshaping the bottom and rails to give it some more tail “kick”. The current rocker numbers are:

Tail 3.3"

Half foot from tail 2,5"

Foot from tail 1,8"

1,5 foot from tail 1,3"

The tail is thick so it could be easily thinned at least 0,3" to get 3,6" tail rocker that has some McTavish style swoop behind the fins. Of course the tail volume would drop a little and in an optimal world I’d propably have the tail a bit wider and outline curvier as the rocker is increased. 

At least my McTavish and Takayama Noah Ka Oi have more tail rocker and the tail rockers accelerate more towards the tail. Both boards ride well, small to 1,5 overhead.

What do you say? Where are the pitfalls and what did I forget? What to expect?



I wouldn’t do it. While I fully understand the frustration of having a board that is NEARLY just right, I think I would explore almost any other option. Breaking into the original, sound glass job to modify would be difficult to do gracefully, and it is likely that you might not get the results you are after. I would, instead:

A) Experiment with different fins and placements.

B) Put the board aside for the bigger days and invest in (or shape) the board you need for the small ones.

C) Sell the complete board and buy one that performs within a greater range of surf conditions.

Of course, this is just MY opinion. I have seen a number of attempts at post-glass re-shaping, and most have been unsuccesful. That the board rides well as is, doesn’t leak, and retains some resale value is good enough reason to not go ‘a hackin’!

That being said, I will admit to seeing a video of Derek Hynde having some success and a shit-ton of fun modifying an existing board, but I consider him quite an exception on many levels!

I’d sell it and shape a board the dims you want.

what would you do with the fin box?

I’d do it and add some “vee” too.  Maybe look at the “Vee” in your other boards.

If you go for it, you can maintain strength and width by scarffing out @ 3/16" of foam at the rails and filling with strong putty to give a thick strong lip to glass on - and you can always add an edge/lip of putty over the glass for strength and sharp edge.

That being said, if you have them, playing with the fins would be an easy start…

You might be surprised at how much flex a glassed board like that has.  I’d route several lengthwise slots in the deck above the tail area, set the board on blocks and add weight to the deck above where you want the additional rocker. Fill those slots with epoxy and carbon fiber tow and let completely cure until rock hard.  Add more weight than you think you need as there will be some springback but I’ll bet you can add at least a bit of tail rocker this way. If you route a couple of deeper slots on each side of the center box, the possibility exists for adding some vee.  Block the rails, add weight and do the epoxy/carbon tow deal but add the weight right above your center box.

Take the sidebites out and move the fin all the way forward. 

Thanks for the ideas. The other option being considered is copying some of the shape, altering the tail part and making a new board with a shaper friend of mine. I’d propably move the wide point a bit towards the tail to give it a little hips and flatten the rocker behind the middle of the board to get a more accelerating rocker at the tail. Does anyone have a McTavish style high performance 3-stage rocker in numbers? (I’ve sold my McTavish Original)

I definitely would not take a router or a sawsall to a decent functioning board.  Buy ,sell or trade and come up with something that suits you.   Taking those oversized side bites out will free it up quite a bit.  Push the center fin forward to at least the mid point of the box.  Should make a big difference.  I would get rid of the Protex rubber duckies and get a Rainbow Azul or Calif Raked Fiberglass fin.  Those Proteks are dogs and famous for drag.

yep don’t do it case closed.

a beautifuly executed board would be sorely missed

the wave you get will be remembered

long after the waves of summer that

make you long for a quickie flicky turn/carve

to adapt to wanting conditions.

when the waves are good enough for this shape

it will be important to have.

the summer board is made for desparate

conditions,smallest is best so’s ya can

flop and spin like a breaker on cardboard .

the long grind of the turn will come soon.

before long a long period swell from

down under winter will grace you

with the voltage to lighht your lights.

make a newie according to your budget

or go to the basilica and light a candle to the patron saint

of summer gratification,or hop a plane to namibia

and get done by a skeleton grindder.

but just leaning back and plugging in a surf dream like reshape a broken gun first.

check the craigs list for your chance at a new fish from a big fat broken gun…



gun cut off two feet up

it will be plenny tik

fo kick.


rreshape a fatty

What ambrose said. Mike

Thanks for the insights. I did some experimenting with the fins and ended up swithcing to bigger 4,25" sides and putting a rather flexy, lexan tupe, 7" Surfco Powerflex fin a bit further up the box (as the board never had any stability issues). I feel the bigger sides and flexing center fin give me more lift and area to push against and keep the tail from sinking too much so I don’t lose so much speed in cutbacks. So far happy, but as you know, you could always try to make things even more spot on…