Author Topic: Stupid Question Fins while driving?  (Read 8326 times)

yugi

  • Cortez Bank Status
  • *****
  • Posts: 2228
    • View Profile
Re: Stupid Question Fins while driving?
« Reply #15 on: October 20, 2016, 04:38:06 PM »
Mercedes Benz tunnel tested all these options for you in the 80s. Their conclusion was: Fin on.. board upside down and fin at the back.


Fins on, fins up and fins forward, if straps losen slightly and traveling on a highway and the boards slide toward rear of vehicle, forward fins then allow the boards fins to catch the straps and would allow the board to be be prevented from sliding backwards off the vehicle onto the highway where other cars could run it over. With fins up and nose foreard, yes fins in back would prevent the board from flying off car forward in the event of a studden and completely hard stop, other then rare instances, I'd rather have board stay on at higher speeds than a quick stop.
Has anyone ever had a board move rearwards on a roof rack? Wind mainly creates lift, and as long as your board is widest in the middle, and you haven't been a total numpty strapping the board on, the board will not be able to move rearwards because the rear strap will prevent it.

I have seen it happen on a few occasions when BOTH straps (front and rear) became loose.

Even with straps way loose Area is right. The board lifts and flies above the roof rack. It doesn’t slip back. A friend tested this for us 300 miles of highway.(No, not on purpose)



« Last Edit: October 20, 2016, 04:48:35 PM by yugi »

Eagle

  • Cortez Bank Status
  • *****
  • Posts: 2426
    • View Profile
Re: Stupid Question Fins while driving?
« Reply #16 on: October 20, 2016, 04:43:06 PM »
Fin forward - fin backward - one fin on and one fin off - upright - and upside down.  With or without bags.  All work fine except if upside down - you need to add a couple twists to stop vibration marking which is hard to remove.

Always tensioned the same with D-straps and never had any issues at highway speeds.  Boards never slip much - but do use Yakima round bars that are super solid and beefy attached solidly with towers clips and locks.  Takes about a minute to strap down and is secure.  About as easy as you can get really with no mechanical springs to break.

One time on a DW run - not on my vehicle - ropes were used.  One knot was not secured properly and nearly lost 3 boards.  Another time a board came undone again with ropes - and the board was destroyed.  So make sure yourself that "your" board is strapped down exactly the way you want before getting on the highway.  D-straps cannot come undone - but the strap can break from UV and wear and tear.  So be aware.
Fast is FUN!   8)
Dominator - Touring Pintail - Bullet V2 - M14 - AS23

Night Wing

  • Cortez Bank Status
  • *****
  • Posts: 2724
  • Piney Woods of Southeast Texas
    • View Profile
Re: Stupid Question Fins while driving?
« Reply #17 on: October 20, 2016, 07:44:50 PM »
The two times I drove down to Galveston, Texas; the distance is 90 miles one way, 180 miles round trip. I drove with my quad + 1 Hammer strapped to my roof racks, sup upside down, fins attached (all 5 of them) towards the back bumper with the nose of my sup forward towards the hood of my truck. Never had a problem on these two trips so for two round trips, that is the equivalent of 360 miles.
Blue Planet Duke: 10'5" x 32" x 4.5" @ 190 Liters (2 Dukes)
Sup Sports Hammer: 8'11" x 31" x 4" @ 140 Liters
SUP Sports One World: 11'1" x 30" x 4.5" @ 173 Liters
CJ Nelson Parallax: 9'3" x 23 1/2" x 3 3/16" @ 78.8 Liters (prone surfing longboard; Thunderbolt Technologies build in Red construction)

ruralwaters

  • Malibu Status
  • **
  • Posts: 63
    • View Profile
Re: Stupid Question Fins while driving?
« Reply #18 on: October 20, 2016, 10:35:39 PM »
What about boards with the "bump" nose such as a Starboard Touring - fin or nose forward?  I've heard that those boards should go deck side down and fin forward to minimize strain on the board from highway speed winds.

Area 10

  • Cortez Bank Status
  • *****
  • Posts: 4057
    • View Profile
Re: Stupid Question Fins while driving?
« Reply #19 on: October 20, 2016, 11:09:10 PM »
The "fins up and forward" advice relates mainly to boards that have significant rocker. There will always be some shapes where a different approach is more aerodynamic. Always use two straps on the front so there is redundancy, and if you use camlock straps, tie off the straps after the cam, and on long journeys check that the straps are still right at regular intervals, and preferably use a bag.

For many years I used to do round trips for surf in the range of 200-500 miles for surf around twice a week. Yes, really. With that kind of mileage you start thinking a lot about aerodynamics as well as safety.

ATX Golder

  • Waikiki Status
  • *
  • Posts: 7
    • View Profile
    • Email
Re: Stupid Question Fins while driving?
« Reply #20 on: October 21, 2016, 08:53:30 AM »
Unless you are only travelling at low speeds I don't understand fins forward at all.  It is an inherently unstable aerodynamic configuration.  If the fin is 100% perfectly aligned with center then in theory its OK, however as soon as it gets off center just a little bit then the wind is pushing it further off center.  This then pushes against your straps and could push them looser.  With the fin at the back if it gets off center by a fraction due to cross wind then the forward wind pushes the fin back into position.

I agree the thinking that a board could start to slip backwards and eventually slip all the through the straps sounds highly unlikely.  One nice thing about stand up boards is that many of them do have handles that you can feed straps through.  If I ever do drive my board from Austin TX to the beach at Port Aransas (5 hours highway), I will string a safety line through the board handle.  If somehow the friction straps get loose the safety line will catch and there is no way the board will come off the roof.  I can see the board through my sunroof so if something is going wrong I should be able to notice pretty quickly and get pulled over and correct it.

stoneaxe

  • Cortez Bank Status
  • *****
  • Posts: 12084
    • View Profile
    • Cape Cod Bay Challenge
Re: Stupid Question Fins while driving?
« Reply #21 on: October 21, 2016, 09:25:25 AM »
Only time I've ever removed a fin is when going into the parking garage at work which doesn't have enough clearance or if I'm stacking a bunch (6) boards on my truck. Fin forward or back makes no difference that I can see. I regularly drive 90 miles round trip for surf at 75-80 mph, no noticeable difference in noise, security, or gas mileage. So I'm fins up and whatever way I approach my truck (nose or tail 1st) is how the board goes on. It simply doesn't make enough difference to matter. I've never had a board slip either forward while breaking or back because of wind regardless of the direction I have it on my racks. The only important thing is to make sure you have it secure before you drive off. I use ropes on my truck and the way I do it a knot could come untied and it wouldn't matter. Kanu-lock dual steel cable straps on my car but usually just one board and I don't drive as fast..65-70.
« Last Edit: October 21, 2016, 09:32:46 AM by stoneaxe »
Bob

8-4 Vec, 9-0 SouthCounty, 9-8 Starboard, 10-4 Foote Triton, 10-6 C4, 12-6 Starboard, 14-0 Vec (babysitting the 18-0 Speedboard) Ke Nalu Molokai, Ke Nalu Maliko, Ke Nalu Wiki Ke Nalu Konihi

BWilliam

  • Sunset Status
  • ****
  • Posts: 288
    • View Profile
    • Mongrel Combative Arts
    • Email
Re: Stupid Question Fins while driving?
« Reply #22 on: October 21, 2016, 10:54:41 AM »
Wha...wait... Have I been doing this all wrong???  :o




:)
Will

Area 10

  • Cortez Bank Status
  • *****
  • Posts: 4057
    • View Profile
Re: Stupid Question Fins while driving?
« Reply #23 on: October 21, 2016, 11:17:09 AM »
Yep, you have.

Fins go on the left-hand side of the car :)

BWilliam

  • Sunset Status
  • ****
  • Posts: 288
    • View Profile
    • Mongrel Combative Arts
    • Email
Re: Stupid Question Fins while driving?
« Reply #24 on: October 21, 2016, 12:26:00 PM »
Yep, you have.

Fins go on the left-hand side of the car :)

Ahh, okay. I'll turn the car around. :)




Will

stoneaxe

  • Cortez Bank Status
  • *****
  • Posts: 12084
    • View Profile
    • Cape Cod Bay Challenge
Re: Stupid Question Fins while driving?
« Reply #25 on: October 21, 2016, 01:04:33 PM »
 ;D
Bob

8-4 Vec, 9-0 SouthCounty, 9-8 Starboard, 10-4 Foote Triton, 10-6 C4, 12-6 Starboard, 14-0 Vec (babysitting the 18-0 Speedboard) Ke Nalu Molokai, Ke Nalu Maliko, Ke Nalu Wiki Ke Nalu Konihi

PonoBill

  • Cortez Bank Status
  • *****
  • Posts: 25864
    • View Profile
Re: Stupid Question Fins while driving?
« Reply #26 on: October 21, 2016, 03:16:09 PM »
Generally fins first because there's less rocker in the tail. Truck racks mean the board overhangs the cab. Nose first doesn't work.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Eagle

  • Cortez Bank Status
  • *****
  • Posts: 2426
    • View Profile
Re: Stupid Question Fins while driving?
« Reply #27 on: October 21, 2016, 03:41:54 PM »
What we do for trips up to Squamish for DW shuttles is to take off the fins and put the tails forward upright.  Has low drag and works fine.

For local transport with fins on - we put noses forward and upright and staggered.  Drag is not a issue at low speeds and also works fine.
Fast is FUN!   8)
Dominator - Touring Pintail - Bullet V2 - M14 - AS23

supsurf-tw

  • Teahupoo Status
  • ******
  • Posts: 1062
    • View Profile
    • Email
Re: Stupid Question Fins while driving?
« Reply #28 on: October 22, 2016, 09:19:22 AM »
Fins on and up nose or tail forward. I prefer tail forward for safety in case of strap slippage. But for GODS SAKE if your board is in a sock with a tied end MAKE SURE THE OPEN END IT TO THE REAR
Boards:

 
8-10 x 31 Egg
8-11 X 32 Double wing Fangtail Tom Whitaker
8-6 X 30 1\2  Inbetweener Tom Whitaker
8-4 x 30 Hyper quad Tom Whitaker (wife's now)
8-4 X 31 1\4.  Round (wide) Diamond Tail Quad Tom Whitaker
 9-4 X 30 1\2. Swallow Stinger Quad Tom Whitaker (ex wifes now)
10-0 Brusurf for teach

SUPJorge

  • Sunset Status
  • ****
  • Posts: 471
    • View Profile
    • Email
Re: Stupid Question Fins while driving?
« Reply #29 on: October 24, 2016, 09:05:55 AM »
Fins on, up, and forward. Use 3 straps, two in the front and one of these through the cabin in case the racks separate from the car roof. Routinely stack two boards this way and drive 200+ miles up and down I-95 looking for waves. Never had a problem.
14' SIC Bullet V2 - 9'1" Naish Hokua X32 LE

 


SimplePortal 2.3.7 © 2008-2024, SimplePortal