Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - rpmooreii

Pages: [1] 2 3
1
Gear Talk / Re: Pics and details of my homemade SUP bike trailer
« on: July 05, 2012, 02:51:46 PM »
that looks nice.  I would have used our old Burely if I didn't have to sometimes cart my youngest around in it still.  How did you extend the arm; ie did you splice in section of conduit or find a matching aluminum section and have it bent to the appropriate angle?

2
Gear Talk / Re: Pics and details of my homemade SUP bike trailer
« on: July 03, 2012, 03:00:46 PM »
MS Aeronautics & Astronautics, 1986

3
Gear Talk / Re: Pics and details of my homemade SUP bike trailer
« on: July 03, 2012, 02:35:59 PM »
I also used the Burley attachment (taken from our old kid trailer) but it is plastic and with the torque induced by the long arm, I am a bit worried about catastrophic failure.  This is one of the areas I am trying to improve...

4
Gear Talk / Re: Pics and details of my homemade SUP bike trailer
« on: July 03, 2012, 02:10:58 PM »
I mocked up an under seat mount and it was highly unstable with all the weight.  The attachment near the bike drops seems to work much better but I have a couple of ideas to improve it :o)

5
Gear Talk / Re: Pics and details of my homemade SUP bike trailer
« on: July 03, 2012, 12:22:34 PM »
Actually it is NOT over-engineered... in fact there are parts that are inadequate for the full load (boards + beach gear) that I am re-working. 

FWIW, I do have a MS in Aeronautics and Astronautics from Stanford and was a practicing engineer prior to hitting up an Ivy for an MBA 20+ years ago...

6
Gear Talk / Re: Pics and details of my homemade SUP bike trailer
« on: July 03, 2012, 12:15:50 PM »
A better pic of my old best friend.  In his younger years, he was certified as a Therapy Dog and was even in a Elle mag photo shoot:



Cosmo, the current Swissy with my boys at Christmas:


7
Gear Talk / Re: Pics and details of my homemade SUP bike trailer
« on: July 03, 2012, 11:15:36 AM »
Well yes and no... he died in 2006 just shy of his 11th b-day which is very old for a Berner and the wheelchair has been in the garage ever since.  We also have a 9yo 120lb Greater Swiss Mtn Dog who still looks and acts like a puppy :)

8
Gear Talk / Re: Pics and details of my homemade SUP bike trailer
« on: July 03, 2012, 09:48:17 AM »
Thanks for the compliment.  Hand weed... a little bit everyday :o)

9
Gear Talk / Pics and details of my homemade SUP bike trailer
« on: July 03, 2012, 09:21:01 AM »
Thought I would take a moment to share the SUP trailer I cobbled together last weekend.  I used some of the ideas of others on this board and added my own twist.  The trailer is crafted from 1/2" galvanized pipe (threaded) and features an upper level for boards and a lower level for chairs, packs, etc.  I will be making several mods after taking it on its inaugural ride on Sunday including shortening the arm between the trailer and bike.

It works great!  Enjoy the pics:









10
Downwind and Racing / Re: Why Box tail?
« on: November 26, 2011, 01:05:13 PM »
I am fortunate to have paddled (and coached) OC-6 for many years on the top crews here in SB and I can confirm first hand the affect of a good steersman esp. on the down swell legs.  OC-6 performance is largely (in fact almost exclusively) predicated on perfect timing and this is exacerbated when trying to catch swells esp. during the second half of a race.  Tired crews tend to lose their timing and even if they appear to be in synch often their hits are at different points and the speed and ability to catch runners drops precipitously.

The top crews w/ heavier paddlers use the momentum effects to their benefit and rarely fall back off swells; so in this case the heavier paddlers are better (same goes for crew where there are no disruptive conditions (ie swells)).  I can personally attest to the fact that there is nothing more fun than being part of a really fast OC-6 crew in a big race (Catalina, Molokai, etc).  The canoe seems to glide forever and it is easy to link rides at high speed.  This is also seen in sports such as downhill skiing where the heavier racers carry accelerate faster and carry more speed through the flats.

Less accomplished OC-6 crews tend to fall off the back of swells and come almost to a stop... in these cases it is advantageous to have a lighter crew (assuming same power output and timing) as there are less inertial effects in getting back up to planing speed.  So, at least in my opinion and personal experience, the physics is fully consistent with the observations made by the above posters.

I have long recommended to new distance SUPers that they should join an OC-6 crew first if they really want to learn the proper stroke, timing, and ability to ride swells and then cross train w/ surfskis which is the best way of promoting the big twist and symmetric paddling required to get a SUP or OC moving well.

...Roger

11
Downwind and Racing / Re: Why Box tail?
« on: November 25, 2011, 08:12:22 PM »
Glad I could help a little bit.  I have enjoyed the forum for some time but am an infrequent poster.  Thanks to everyone that makes this a fun place to waste some time  :)

...Roger

12
Downwind and Racing / Re: Why Box tail?
« on: November 25, 2011, 06:23:33 PM »
Hmmm, you noted that the paddler moves around in response to variability in the surface conditions as a reason why a light board is analogous to unsprung components in a vehicle.  In a nutshell, the principal of reducing unsprung weight is to have light weight components (ie the board) react to variability in surface conditions so that the much heavier sprung weight (in this case the paddler) is not disturbed and the ride is therefore smoother and more efficient.  Perhaps I just do not understand your analogy but it seemed to me that you were suggesting that a paddler's movements in response to surface variability was similar to the unsprung components in a vehicle but just the opposite is true.  A light board would only be beneficial if the weight of the paddler was sprung and basically steady and the board alone reacted to the variability thus minimizing non-beneficial motion (ie motion not contributing to forward speed).  Unfortunately we all know this is not true... paddlers move around to drop in on waves and to adjust for destabilizing surface conditions (chop, side swell, etc)

Also, please note that I never said that a paddler's weight was akin to a "bunch of pumpkins" and I FULLY agree that a paddler's movement affects the way a board moves BUT those movements have little to nothing to do with physics of sprung vs. unsprung weight rather they involve momentum effects.  The benefits of unsprung weight are essentially the capability to minimize energy losses by having "light" components react to changes in the surface.  Wheels and suspension have far greater capability to move independently, in response to surface variability than does a 25lb board under a 200lb paddler where the "suspension" is one's ankles.  If the suspension also includes the paddler's legs as implied by PB then the unsprung weight is far greater (board + legs+feet) and no longer a function of board weight only which supports my hypothesis that light boards alone are not the benefit that everyone claims.

Rather, paddler movements are momentum transfers that get the board moving in a desired direction or for creating that extra push to make it over the next swell.  Hell, when I was a kid in the 70s I could pump my skateboard uphill w/o ever pushing off but again this had almost nothing to do w/ unsprung weight and everything to do w/ energy transfer between the motion of my body to the motion of the skateboard.  Same hold true for a SUP or surfski when surfing as outlined above.  FWIW, I do have a bit of experience in dynamic systems and none of my points have been related to static analyses.

I guess we can just agree to disagree. I have no interest in having a physics debate on a SUP forum and I don't think the others on this site do either so I will refrain from further posts on the subject.  In the end, we all believe what we want.

Thanks!

...Roger

13
Downwind and Racing / Re: Why Box tail?
« on: November 25, 2011, 03:07:16 PM »
Not trying to argue but:

1.  The paddler is the sprung weight in the case you describe (knees and ankles supporting the body and reacting changes)...  not the unsprung weight...

2.  The unsprung weight is the board BUT it is not free to move in the same manner as a suspended land vehicle.  The suspension system in a car allows the wheels to follow the undulations in the surface (track) while the body stays level and (largely undisturbed) maximizing efficiency.  In the case of a SUP the board follows the changes in surface but so too does the body in most cases.  I have yet to see a paddler react in such a manner that keeps the head moving perfectly level regardless of the movements of the ocean.  If there was a paddler that could react to all the changes in the water with his/her ankles in such a way that his/her body (incl. the heavy legs) remained undisturbed I will happily revise my comments.

There are clearly inertial effects that make a lighter board better... such as spinning around in a turn but we have been largely discussing the drag of a board moving across the water in a straight line and in those conditions, I still submit that total system weight (board + rider) is the important factor and that board only weight is a second order effect.

Hope everyone had a nice t-giving!

...Roger

14
Downwind and Racing / Re: Why Box tail?
« on: November 25, 2011, 10:15:46 AM »
The entire system on a SUP is unsprung... this my comments re: losing 10lb of body weight being cheaper and more effective than buying a board 10lbs lighter.

15
Downwind and Racing / Re: Why Box tail?
« on: November 23, 2011, 06:50:02 PM »
1paddle2paddle:  Thanks for your comments.

At the limit (guys like the Chulupsky bros), the lighter board/ski will be better and probably does make a small difference over long periods of time (4 hrs plus) but I submit that for the vast majority of us the weight of the board (within reason) has little to no bearing on our speed or results.  In addition, the manufacturers make MUCH more $ margin on the expensive, super high end board so, of course, all the sponsored riders will have them... and that drives the mere mortals (esp. the ones with hefty pocketbooks) ante up the extra dough for the super light board/ski.

In addition, in some conditions a heavier board will actually be BETTER (theoretically at least) than an ultralight because of momentum effects.  For my money I never buy the light carbon skis/boards as I know it will not make a difference in MY performance.  Your results may vary esp. if your "think" the lighter board is faster.  The mental edge from such a board is likely to have a bigger effect than that of the weight.  A bit ironic but true.

Lastly, I am not dodging the questions of which design is "better" but the unfortunate truth (in my opinion at least) is that there is an optimum design for every set of conditions... which not only vary day-to-day, and hour-by-hour, but is some cases swell-by-swell.  The "best" design is simply a compromise for the anticipated conditions over an entire race but again I am a firm believer that the best paddler (combo of technique, fitness, stability, mental) wins regardless of the board design as long as he/she is not riding something was designed for completely different conditions (ie downwind board in glass conditions).  So wide tail vs. pintail (within the limits we are discussing) is largely irrelevant (ie a second order effect) from a hydrodynamic standpoint in my experience EXCEPT as it relates to stability (see my comments earlier re: surfski designs) and therefore the ability of the paddler to go as hard as he/she can w/o checking for the entirety of the race.  In that case a wide tail typically creates a more stable platform and the paddler can go harder for longer w/o stability issues.  Of course, one can create additional stability in other ways as well (ie a wide tail is not the only way to make the board more stable as we all know).

One last thing... there is no doubt that C. Baxter wins many of the long open ocean races because of his ability to read the ocean, link swells, etc BUT he did beat Danny Ching this year at the BOP.  That win had little to do w/ swell riding and everything to do w/ ability, power, and stroke technique.

I have enjoyed this discussion and I hope that I have not burst the bubbles of those that hope the next best board (or the pricey light carbon model) will vault them from mid pack to the front but it simply won't happen.  But hell, buy that new board anyway... we all know how fun it is to get a new toy! And the good news is that there is a simple path to the front... more time on the water, stroke coaching and targeted hard training.

See ya on the water...

...Roger

Pages: [1] 2 3

* Recent Posts

SimplePortal 2.3.7 © 2008-2024, SimplePortal