adding channel to bottom of a race SUP

[GlideMarko]

Thinking of adding channel to bottom of a race 14' SUP... currently bottom is flat without concaves. the board is already quite fast and stable.
I assume the simplest would be square - as SIC RS last 2/5 of a length? Any thoughts?
It's additional (not necessary) part of a project as board is dug-out but the water does not drain properly from standing area as it is deepened and not tilted to the tail. not drain holes.
1.option - just adding drain holes
1.option - straighten out and tilt deck to the tail and add bottom chanel (this in not necessary but it would fun - transfer voulume from bottom to the standing area)
I dont know how much would be weight change and stability if the standing area is aprox 2cm higher.
photo - black lines - current situation (blue for water  of course )
red lines - new situation
also drawn drain holes for 1.option
drawing just for info

[burchas]

What are trying to achieve with the added channel? Do you need better tracking?

As for the draining holes. Open ended design with tilted deck makes most sense to me.
It's the most simple straight forward solution but you are loosing some stability and paddle
leverage with the higher deck.

Another option is somewhere in between with open ended design without tilted deck. single
drain hole in the middle, just under the handle. Worked very well for me even in very demanding
conditions:

https://www.dropbox.com/s/vw0h9p2rtaf4jbp/drain.mp4?dl=0

Board was very fast in flat water, no issues with water on deck. You can see the bulk of water moving
out of the deck  very quickly and the little excess is dealt with by the drain hole. In flat water the deck
was pretty much dry.

[PonoBill]

I took the channel idea to an extreme, with my 18' Speedboard that UPS freight turned into two 9 footers. I wanted to see if I could make a board track without fins. The answer is yes, but then you can't turn it. It's sitting on my wall at the shop. You could save yourself some time by taking it--it's yours.

A channel won't make the board faster unless there's some other dynamic involved in the design. There's more skin friction because there's more skin, and there's more turbulence because there are more changes to the surface. Eliminating or reducing fin drag, or perhaps adding some dynamic potential by pumping or leaping around on the board. Other than that, it's one of those things that board makers try every so often that sells more boards but doesn't do much else.

[GlideMarko]

Here are photos how much water stays in standing area instead draining to the tail. Also, sidewalls on the back gets lower right about the paddle (stroke) exit, which if you splash into cockpit, water flows right into standing area instead draining trough tail.
Adding chanel would be primarly for stability compensate as some would be lost due to rising the standing area as drawn. Even if adding 0.5kg of material by doing all the cuts&new lamination I think it's still better than 2L(2kg) of water in standing area.
The new model has drain holes and bottom chanel, but also closed tail.
Or, just drill some drain holes and no other change.
Other than this issue, the board is very good -  fast and stable for 24'wide and picks really nice small (30cm) waves. 

[GlideMarko]

a month ago I got drail holes on the board and handle changed to neoprene handle instead of surf handle. holes and handle work great and i'm happy with the change. at 24 wide the board is very stable on flat and after 3months of usage i'm gettin little bit faster - 1km trial 5:50 and 5:46. maybe for some serious speed i would need little bit narrower and little less rocker board.
https://connect.garmin.com/modern/activity/3992374582

C U on H2O, cheers