Correct volume calculation for new board buyers - Page 4

Floyd · 25th February 2009, 02:09 AM

I`ve come a bit late to this thread but for what its worth ;

Reserve volume calculations are an absolute waste of time for heavier sailors especially.

At a rider weight of say 60 kg a reserve volume of 20 litres would be loads. At a rider weight of 100k it would not !!

What we should look at is the RATIO of volume available to rider weight.

ie I summise a ratio of 1.3 will give the volume of board uphaulable.
(ie for 60 k rider volume reqd would be 60 x 1.3 litres. (ie 78 litres)(reserve 18)
and for a 100k rider it would be 130 litres to have equal flotation !!!!(reserve 30 !!!)

In other words a 100k rider to have same reserve buoyancy would need 30 litres reserve whereas his 60k sailing partner would only need 18 litres.

Imagine a yacht with 100 litres reserve.It would be almost sinking.
A board with 100 litres reserve would be easily buoyant.

Reserve volume measurements should be despatched to the same place as wooden booms !

Forget them !!!

Look at floation ratios.

Ken · 25th February 2009, 11:44 PM

Floyd,

Regardless of floation ratios, I want to see volumes. I know exactly what volume I need to slog home in less than 5 knots and not have the board under water. The last two small boards I purchased, I specifically chose a volumes so I wouldn't have to struggle in no wind situations. A Hi Fly Move 105 (105 liters). 2008 iS 111 (108 liters).

In my opinion, it is just plain stupid for a manufacturer to not include actual volumes in their promotional materials and on their boards.

My favorite lake sailing spot has prevailing south winds and a big wind shadow for about
50 meters from shore. It can be blowing 25 knots outside the shadow and 5 knots inside. I have an 80 liter board that I won't use at this sailing location because I prefer not to sail with it 10 - 20 cm underwater.

For some of us, REAL volumes are important to know.

wiindz · 26th February 2009, 06:49 AM

Quote:

Originally Posted by Floyd

I`ve come a bit late to this thread but for what its worth ;

Reserve volume calculations are an absolute waste of time for heavier sailors especially.

At a rider weight of say 60 kg a reserve volume of 20 litres would be loads. At a rider weight of 100k it would not !!

What we should look at is the RATIO of volume available to rider weight.

ie I summise a ratio of 1.3 will give the volume of board uphaulable.
(ie for 60 k rider volume reqd would be 60 x 1.3 litres. (ie 78 litres)(reserve 18)
and for a 100k rider it would be 130 litres to have equal flotation !!!!(reserve 30 !!!)

In other words a 100k rider to have same reserve buoyancy would need 30 litres reserve whereas his 60k sailing partner would only need 18 litres.

Imagine a yacht with 100 litres reserve.It would be almost sinking.
A board with 100 litres reserve would be easily buoyant.

Reserve volume measurements should be despatched to the same place as wooden booms !

Forget them !!!

Look at floation ratios.

the ratio idea is nice, but you have to realise that unless your sailing on the dead sea, a 60 kg sailor would never be able to uphaul on a 78l board! you must add the wieght of the board and the rig (everything being wet) and then your wieght with your harnais and watever other clothing you wear wet. after you add that all together, then you aply your formula. for the average jo, i would say that you should add about 20kg to your wieght, so for a 60kg sailor, it would actualy take 80 x 1.3= 104l wich makes a lot more sense then 78l!! anyways just thought that somebody should point that out...

fair winds!

Floyd · 26th February 2009, 04:34 PM

You are obviously correct about adding weight of rig and board and suit etc. Idea is to use ratio on all up weight.Its not a definitive answer but way more accurate for different weights of riders than adding reserve volume.(ie a arbitary constant)
Ken
Agree actual volumes should be quoted.

PS
I reckon there are quite a few 60k riders who can uphaul a 78 litre board.(I know of one definitely)

Point is that lighter sailors with 20litres reserve have way more chance of uphauling than a 100k rider with same.

Not sure uphauling should be acid test.Its getting back in virtually nothing AND being able to uphaul if you drop rig. (They can be mutually exclusive; ie uphaul rig and slowly sink to have to start again)

Erik Loots · 26th February 2009, 10:29 PM

Volume is very handy for:

---Amateur sailors, gybing, uphauling sail, learning new stuff
---Real world wind, wind going from 20kn back to 10kn in just a few minutes

Volume isn't handy (from a speedsurfers point of view):

---When you want to go fast on a tight course (90 till 115 degrees)

So I would NEVER publish a lower volume on a board ment for freeriding, freeracing, etc. A design could work real fine, and plane real fast, but volume can't be lower than stated.

Volume is something that every surfer reconizes really quick. Be smart you guys @ starboard, and I know you guys are smart enough to solve this one for the future

wiindz · 27th February 2009, 04:23 AM

Quote:

Originally Posted by Floyd

PS
I reckon there are quite a few 60k riders who can uphaul a 78 litre board.(I know of one definitely)

let me rephrase that, uphaul in nothing! im sure a 60kg sailor could find a way to uphaul on a 78l board if he was using a relitively small sail, like say a 4.5 coupled with a lite carbond boom and lite carbon mast in a fair bit of wind, so you just pull up the sail and grab the boom right away putting most of your wieght on the sail. in that scenario, yes, technicaly you did uphaul the sail, but i think what we are talking about here is when you are underpowered so you cant realy put much wieght on the sail... a board that you uphaul on is in most cases your light wind board, havent seen many people over 45kgs with a 80l board as their light wind board!!!

p.s. totaly agree with you ken, the real volume should deffinately be stated on the board call it what you like for marketing sake, but at least give the real volume in the little specs area... just something to think about *board!!

steveC · 27th February 2009, 12:51 PM

Come on guys, uphauling a 78 liter board? You have to be kidding.

If you lose the wind, and can't waterstart, you simply have to swim everything in. The idea that you can just uphaul your way out of reality is simply not practical.

Floyd · 27th February 2009, 05:10 PM

Steve
Dont think anyone is saying low volume boards can be uphauled out of trouble at all; and its not really the issue.
Point is for heavier sailors that impossibility to get going arrives loads earlier than for lighter sailors if we insist on using "reserve" volume as a guide.
You see it as bordering on impossible for a 60k sailor to uphaul 78 litres but probably would not question a 100k sailor claiming to uphaul 125 litres who would actually have relatively less real reserve volume. (A 60k rider on 78 litres has exactly same flotation available as a 100k rider on 130 litres)

PS Both examples are possible. I can just uphaul 125 litres.My daughter at 60k +( not saying how much + she`d kick me) can (just) uphaul 80 litres. (seen her do it) BUT neither situation are advisable.( And neither possible in chop/swell etc etc)
A lot also depends on width of board obviuosly. (and your ability to keep uphauling in knee deep water)
Seen Nico Reynes (French Wave champion) uphaul a tiny board (sub 70) without an uphaul ! Doesnt mean it is common practice/advised.

Time to forget constant reserve volume. We should talk float ratios.(ie Ratio of 0.8 for speed ?;1 for wave sailors ?; perhaps 1.2 slalom; 1.3 freeride and 1.6 beginners.
Think you get idea. (All ???)

wiindz · 28th February 2009, 09:03 PM

i can see the 1.2 for slalom, 1.3 for freeride and 1,6 for begginers working but the 1.0 for wave and 0.8 for speed, hmmm these calculations only help you out to figure out how much volume you need to uphaul, once you can waterstart, its watever the wind is doing and the water conditions that dictate what size board your gona be using.... since i dont think that realisticly tou can uphaul at a 1/1 effictively or at a 0.8/1 ratio effectively, those two might be a little off, but the are three make total sense ;p

Floyd · 1st March 2009, 02:26 AM

I see your point but dont forget I`m only talking guide figures not absolutes. (Starting points ?)
Generally speaking well powered up wavesailors will be on around their own weight in kg in lires (if you get my drift) but I accept there are huge exceptions to this whch suit riders fine.
I remeber years ago looking at Bjorn Dunkerbecks lightwind waveboard.It was 97 litres !!! His weight ? Around 97kg . At time my weight was also 97 kg. No way could I get going in winds he got that going. (He was on it when I would have needed 120 ish and a bigger sail)
Perhaps a wavesailor/speedsailor doesnt need a guide anyhow though ???

Good winds

25th February 2009, 02:09 AM	#31
Floyd Member Join Date: Sep 2006 Posts: 459	Reserve volume is useless !!! I`ve come a bit late to this thread but for what its worth ; Reserve volume calculations are an absolute waste of time for heavier sailors especially. At a rider weight of say 60 kg a reserve volume of 20 litres would be loads. At a rider weight of 100k it would not !! What we should look at is the RATIO of volume available to rider weight. ie I summise a ratio of 1.3 will give the volume of board uphaulable. (ie for 60 k rider volume reqd would be 60 x 1.3 litres. (ie 78 litres)(reserve 18) and for a 100k rider it would be 130 litres to have equal flotation !!!!(reserve 30 !!!) In other words a 100k rider to have same reserve buoyancy would need 30 litres reserve whereas his 60k sailing partner would only need 18 litres. Imagine a yacht with 100 litres reserve.It would be almost sinking. A board with 100 litres reserve would be easily buoyant. Reserve volume measurements should be despatched to the same place as wooden booms ! Forget them !!! Look at floation ratios.

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25th February 2009, 11:44 PM	#32
Ken Member Join Date: Aug 2006 Location: Dallas, Texas USA Posts: 797	Floyd, Regardless of floation ratios, I want to see volumes. I know exactly what volume I need to slog home in less than 5 knots and not have the board under water. The last two small boards I purchased, I specifically chose a volumes so I wouldn't have to struggle in no wind situations. A Hi Fly Move 105 (105 liters). 2008 iS 111 (108 liters). In my opinion, it is just plain stupid for a manufacturer to not include actual volumes in their promotional materials and on their boards. My favorite lake sailing spot has prevailing south winds and a big wind shadow for about 50 meters from shore. It can be blowing 25 knots outside the shadow and 5 knots inside. I have an 80 liter board that I won't use at this sailing location because I prefer not to sail with it 10 - 20 cm underwater. For some of us, REAL volumes are important to know.

26th February 2009, 04:34 PM	#34
Floyd Member Join Date: Sep 2006 Posts: 459	You are obviously correct about adding weight of rig and board and suit etc. Idea is to use ratio on all up weight.Its not a definitive answer but way more accurate for different weights of riders than adding reserve volume.(ie a arbitary constant) Ken Agree actual volumes should be quoted. PS I reckon there are quite a few 60k riders who can uphaul a 78 litre board.(I know of one definitely) Point is that lighter sailors with 20litres reserve have way more chance of uphauling than a 100k rider with same. Not sure uphauling should be acid test.Its getting back in virtually nothing AND being able to uphaul if you drop rig. (They can be mutually exclusive; ie uphaul rig and slowly sink to have to start again)

26th February 2009, 10:29 PM	#35
Erik Loots Member Join Date: Aug 2006 Location: The Netherlands, Alkmaar Posts: 109	Volume is very handy for: ---Amateur sailors, gybing, uphauling sail, learning new stuff ---Real world wind, wind going from 20kn back to 10kn in just a few minutes Volume isn't handy (from a speedsurfers point of view): ---When you want to go fast on a tight course (90 till 115 degrees) So I would NEVER publish a lower volume on a board ment for freeriding, freeracing, etc. A design could work real fine, and plane real fast, but volume can't be lower than stated. Volume is something that every surfer reconizes really quick. Be smart you guys @ starboard, and I know you guys are smart enough to solve this one for the future

27th February 2009, 12:51 PM	#37
steveC Member Join Date: Aug 2006 Posts: 639	Come on guys, uphauling a 78 liter board? You have to be kidding. If you lose the wind, and can't waterstart, you simply have to swim everything in. The idea that you can just uphaul your way out of reality is simply not practical.

27th February 2009, 05:10 PM	#38
Floyd Member Join Date: Sep 2006 Posts: 459	Steve Dont think anyone is saying low volume boards can be uphauled out of trouble at all; and its not really the issue. Point is for heavier sailors that impossibility to get going arrives loads earlier than for lighter sailors if we insist on using "reserve" volume as a guide. You see it as bordering on impossible for a 60k sailor to uphaul 78 litres but probably would not question a 100k sailor claiming to uphaul 125 litres who would actually have relatively less real reserve volume. (A 60k rider on 78 litres has exactly same flotation available as a 100k rider on 130 litres) PS Both examples are possible. I can just uphaul 125 litres.My daughter at 60k +( not saying how much + she`d kick me) can (just) uphaul 80 litres. (seen her do it) BUT neither situation are advisable.( And neither possible in chop/swell etc etc) A lot also depends on width of board obviuosly. (and your ability to keep uphauling in knee deep water) Seen Nico Reynes (French Wave champion) uphaul a tiny board (sub 70) without an uphaul ! Doesnt mean it is common practice/advised. Time to forget constant reserve volume. We should talk float ratios.(ie Ratio of 0.8 for speed ?;1 for wave sailors ?; perhaps 1.2 slalom; 1.3 freeride and 1.6 beginners. Think you get idea. (All ???)

28th February 2009, 09:03 PM	#39
wiindz Member Join Date: Jan 2009 Posts: 61	i can see the 1.2 for slalom, 1.3 for freeride and 1,6 for begginers working but the 1.0 for wave and 0.8 for speed, hmmm these calculations only help you out to figure out how much volume you need to uphaul, once you can waterstart, its watever the wind is doing and the water conditions that dictate what size board your gona be using.... since i dont think that realisticly tou can uphaul at a 1/1 effictively or at a 0.8/1 ratio effectively, those two might be a little off, but the are three make total sense ;p

1st March 2009, 02:26 AM	#40
Floyd Member Join Date: Sep 2006 Posts: 459	I see your point but dont forget I`m only talking guide figures not absolutes. (Starting points ?) Generally speaking well powered up wavesailors will be on around their own weight in kg in lires (if you get my drift) but I accept there are huge exceptions to this whch suit riders fine. I remeber years ago looking at Bjorn Dunkerbecks lightwind waveboard.It was 97 litres !!! His weight ? Around 97kg . At time my weight was also 97 kg. No way could I get going in winds he got that going. (He was on it when I would have needed 120 ish and a bigger sail) Perhaps a wavesailor/speedsailor doesnt need a guide anyhow though ??? Good winds