Thursday, May 21, 2020

The Endless Summer In Search of the Perfect Roll Tack

https://drive.google.com/uc?export=view&id=1VkrBOkGRGpFRoj_x1AiGmJ-hrwLpdyLX

Roll Tacks are Magic. I remember seeing my first Opti Roll tack when I was 9 or 10 with an older sailor demonstrating off the Opti dock for the rest of the group. It didn't seem possible  -  how could the sail not luff as the boat cut through head to wind?

Roll tacking allows you to trick the wind and to play in the boundary layer between wind and water. By rolling the boat to windward you 'fan' the sail at the moment it would luff. Then, as you flatten on the new tack, you put an extra big gust into her and accelerate.

Roll tacking the Opti a super aerobatic maneuver! Imagine if a gymnast, wrestler or tennis player had to operate on a constantly moving platform?! The boats changes balance in response to how you move, so movements are precisely choreographed to have a desired effect.

The keys to a great roll tack are:
     1. Minimizing drag from the sail (no luffing!), hull and rudder.
     2. Rolling at the right time and the right amount or the conditions.
     3. Establishing flow over the sail and foils as you exit the tack.

These keys are true across all boats that roll tack. The styles and mechanics differ from sailor to sailor and of course according to different wind conditions. Here's 3 sailors I picked out from last weekends light air practice who have been honing their technique for years, and show unique styles that get it done.

Please note that it is blowing a maximum of 2kts and we wouldn't ordinarily start a race in these conditions!  


https://drive.google.com/uc?export=view&id=11AchATsH7lu1EeJmd-Esy7UfjyEVMzim
KJ enters the tack with his eyes on the sail, holding the end of the tiller extension, and shoulders in. 
https://drive.google.com/uc?export=view&id=197woA_KxzGbMOdafq3Ile56ZdfHB_rEN
He finds the right time to hop up to the rail, just before the sail luffs (note eyes still on the sail), and pushes the tiller a little more. Eyes, shoulders and knees are all facing forward! 
https://drive.google.com/uc?export=view&id=1cnpmF-21YPGNlRXKp8axc2MihxXHRRBu
A nice job ducking the boom! I also like that the hand holding the mainsheet is in at his chest - not clinging to the rail!  If you look closely at the masthead wind-indicator, you will see the trickery of the roll tack! The sail thinks it should still be full on port tack! 
https://drive.google.com/uc?export=view&id=18hIHQqt9nk4AuWaMpzqzwn5Zj1HHGhSJ
Now the athletic part - leaping across the boat, but landing smoothly. KJ's Tennis background at work! KJ  uses the tiller hand to stabilize on the rail for less than a second. The sail still thinks its on port. 
https://drive.google.com/uc?export=view&id=1Vnf_EX1jc2kEvsrxeOcNKgqI2JrNjBwO
Now as the sail flops and pops to starboard tack, and KJ is re-establishing flow. The rudder gets pushed behind the back to centerline, and the left knee goes to the bottom of the boat, to make the weight transfer smoother. The right knee being over the bulkhead keeps KJ's weight forward, and if you look at the waterline you can see the boat is well balanced - no stern drag!
https://drive.google.com/uc?export=view&id=18a5lTE6gwdYfMyDsu8_3E3irzQZ9dcPM
Exiting the tack: Tiller 'knifed' away, eyes on the sail, mainsheet eased, to be trimmed in smoothly a second later. Slight splash from the overflatten, but come on it was less than 2kts of wind!






https://drive.google.com/uc?export=view&id=1HLmBfiiuXK4yh_-V-gf3zn_XPcg6_lJT
Cody sailing 'shoulders pressed' before the tack.
https://drive.google.com/uc?export=view&id=1ajzOEb7SQif5FDGJFVb-olwli29AKuqq
Cody puts his shoulders in to initiate the turn.
https://drive.google.com/uc?export=view&id=1SRK_RJT-LzxmtNDz1n3ZmDFD_cKkLLHc
Cody Rolls the boat to windward, filling the sail through head to wind, eyes forward, holding the end of the extension up. Sail trimmed in to centerline.
https://drive.google.com/uc?export=view&id=1wQ9jNUQ3DdHhOCwsUhSP5VsJLf8kA1q5
...As he drops his shoulders to just barely duck the boom, the tiller extension gets pushed down to the floor as well. Note his head is even now still looking forward!
https://drive.google.com/uc?export=view&id=1XGusZHbsVZrLDOAryJuZWcd9OC5abuLn
Beginning to cross the boat, he bumps the boom up to centerline a little bit. Is this fast?! The Etchells sailors who pull the main traveler all the way up to fill the sail before easing it off on the new tack say yes! 
https://drive.google.com/uc?export=view&id=1qyPRSyZ9ZRGrlLavlRwzS2tNqgva-Ljt
Bracing the tiller and leaving one leg to leeward for a smooth weight transfer. Great balance and concentration in this picture.
https://drive.google.com/uc?export=view&id=1i1bqfQr-bcs_XNkSEsZDzbVCP_zU3nFS
Building flow before the acceleration. See how nicely the sail fills, and the tiller hand ready to knife in the dagger!
https://drive.google.com/uc?export=view&id=1im9oninwvlv2sLeYmPese3A-RnPgL3g-
Mainsheet eased aggressively (but correctly for the apparent wind - look at the wind indicator). Tiller knifed away so more of the rudder enters the water smoothly.
https://drive.google.com/uc?export=view&id=1U_wKlTj6VjoIFD4rgwXZrhIgYbqnQLr4
Full rudder away knifing action and Cody's weight is more centered in the boat than 2 frames ago. He's trying to minimize the splash you see to windward...but its blowing less than 2 kts!
https://drive.google.com/uc?export=view&id=16I0wQ8IoTRIkC2rD4ocwsWNt9Lps1Don
Left hand still holding the mainsheet - Cody essentially does a smooth 'bicep curl" to trim in after the tack. Comfortable steering behind the back as well! Windward heel yes, but the top batten 'leech' telltale appears to be flowing, and it's flat water conditions. I call this "upwind kiting." 




https://drive.google.com/uc?export=view&id=1XysY27U8WqNLhWtxR-PGs8eavZYzSGmn
Gil's upwind position pre-tack. Unlike Cody who always steers with the extension, Gil prefers to hold the tiller almost directly when in the boat. Both styles work.
https://drive.google.com/uc?export=view&id=1puyWHl6PJrwztGDuCzQC9tOR9rTkV-cW
Shoulders in and transitioning the right hand from the tiller to the end of the extension. Body in and a little rudder initiate the turn.
https://drive.google.com/uc?export=view&id=1BqqILA4zjI9vb_jM0Lzzx8kzqA6qBPz0
Trimming the sail to centerline and rolling at the right time. Smaller sailors may have to roll a little later so they are not fighting soo much of the force of the sail.
https://drive.google.com/uc?export=view&id=172N_0oH308o0U6kqhywCKJkChuDzACWk
Gil gets enough roll by putting his butt out (rail to the water)  Eye's still forward.
https://drive.google.com/uc?export=view&id=1GoMmum1zkoi8AI4zv4relwjh-cqs3faT
Barely ducking the boom with his Coast Guard Approved lifejacket! Feet are under Gil and knees together (the "crouching tiger" position!)
https://drive.google.com/uc?export=view&id=1xB7pIupBKqD3_Dry0T6EA896vsVJCa3r
Springing accross the boat and keeping the mainsheet trimmed in.
https://drive.google.com/uc?export=view&id=1ATTAp3zZzRWlFQWijfC0nyOMLxNBGMZI
Sailor and rudder both completely airborn! Mainsheet eased aggressively, rudder knifing away to prepare for re-entry to the ocean! Gil is forward to the bulkhead, but not trying to push in front of it - you can see the hull trim is perfect and if he tries to go too far forward (some coaches teach to 'kiss the airbag) the bow will bury.
https://drive.google.com/uc?export=view&id=1iybin0nFaK6X9n8mdLUadZPhMt0VOcen
Extreme rudder angle for extreme light air. Excellent example of howe to "counter" - Gil presses his weight back to leeward and onto his left leg to stop the boat from over-flattening.
https://drive.google.com/uc?export=view&id=1wcTm6KdMXL3Q6LTI7SCYhFx1lZExDTMO
Eyes on the sail as he trims in smoothly. Slight splash from the hull, but no splash from the rudder! Weight centered in the boat.
https://drive.google.com/uc?export=view&id=1vvu6I8OkX801BFiLcmem9N49j2U2q_7z
Full trim (same 'bicep curl' trimming technique as Cody, but obscured by the body), eyes on the sail, rudder straight and a super loose 2 finger grip on the tiller extensions as the sailor goes from the athleticism of the tack to the feel and balance of straight line speed.




These for sure weren't the  only sailors laying down saucy tacks in our last practice and we watched the videos of everyone with the sailors last Sunday evening.  Im alway willing to text sailors that asked their own tacking vides!  Video is so so helpful for sailors visualization of their body movements, as well as seeing the telltales and wind indicator in slow motion. And we all find things to copy from our friends!   One thing you may notice is that all 3 tacks above were port-to-starboard. It just so happens that all 3 sailors are right handed and in fact, their tacks from starboard-to-port were not as good!! This is yet another way video helps us notice the non obvious, and gives us techniques to focus on for the next practice!

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