View Single Post
Old 26th October 2006, 09:34 PM   #2
Dream Team - School Guru
Join Date: Aug 2006
Posts: 2,177
Default RE: Volume old and new boards

Hi Johan,
I've pasted your questions in here and will try to answer them individually.

My old boards are a Copello 285 course race and a Bic Vivace 270 from the mid 90's. Copello 285 / 57 / 112L Bic 270 / 57 / 96L.
I use the 285 with a 7.4, 6.6, and sometimes with an 8.9.
I use the 270 with a 6.6, 5.5, 5.0, and sometimes with a 4.6.
Q: Will a new board (Isonic 105 233 / 63 / 105L 5.5-8.5) have the same flotation as my 285?
No, but it may have the same volume "behind the mast foot" as your older narrower boards and therefore give you the same amount of "float" in the areas of the board where you actually must stand and apply your weight to the board when not moving. It also may be a little more stable (even if it doesn't float as high) due to the additional width which may also help it to plane a bit earlier.
Your old boards had a very long and pretty flat rockerline, the new boards have a very short a "flat from the footstraps back" rockerline.
Your older boards had some volume all the way up to the nose, (where you never put your weight) but the newer shorter boards have far less volume ahead of the mast foot slot. So, you may need to change your tacking technique a little (to keep the nose from sinking or "pearling") when you shift your weight from behind the mast foot to ahead of the mast foot momentarily as you step "around", but this can be easily remedied by stepping over the lower part of the mast with the sail raked all the way back rather than stepping forward of the mast foot.

Will I be able to pull up my sail like on the 285?
At a dead stop, in fresh water, the Isonic 105 may tend to be slightly
deck awash with your 185 lbs. I'd have to try that combination but I don't weigh 185 lbs. and I haven't sailed the Isonic 105 I have in fresh water yet. The Isonic 111 should be better in this respect.
If you can uphaul your 96 liter Bic on the lake, then the Isonic 105 (with 9 liters greater volume) should be easier.
Is 285 / 57 / 112L equal to 233 / 63 / 105L?
NO! But with the change in volume distribution (further back and wider on the 105/111 liter Isonic) the difference may not be as great as the numbers suggest. If the 105 liter Isonic floats you well enough to uphaul, on fresh water, even with the deck slightly awash, then this board should work for you.

How do I pick a board for the 7.4, 6.6, and sometime an 8.9?
Do I go for volume or width or both?
If getting back to the beach when the wind dies is important, (and it sounds like it is for you on your local Raleigh area lakes) then you really have to make your choices based on adequate volume to get you back to shore slogging along in sub planing conditions.
Extra width, and a shorter length, as long as you have adequate volume to slog home, could actually be considered "+'s" here as more width will get you planing sooner, and the shorter length simply means there's more volume where you can use it as "float" while slogging.

Why can a 248 / 71 / 115L take 6.5 - 9.5 and a 245 / 67 / 120L only take 5.5 - 8.0 with 5L more?
I will "guess" you are talking about the recommended sail sizes for different boards based on manufacturer's recommended sail size charts. I've never quite understood what these charts base their recommendations on, but I know that some mfg's. (Starboard in particular here) do quite a bit of testing and use the post test results to recommend particular sail size ranges for the boards tested.
You can always use a slightly smaller or larger rig, and it may work for you individually, but as a result of the testing, they've probably tried the same combination and found that the board gets "too big" for the conditions if you go smaller that recommended, and the board feels unbalanced and does not give any better marginal condition (for the board) performance with sails larger than recommended.

Is it possible to put a 9.0 on the 120L board?
I have a 118 liter 100 cm wide Formula board that works very well with 9.0 m2 rigs. Doesn't plane as early as a 140-160 liter formula board with the same width, but it works.
As boards get smaller and narrower, their ability to handle huge sails diminishes as they don't have the volume and width to really give any kind of performance in windspeeds that support planing on wider boards with higher volumes in true 9.0 m2 conditions.
You can certainly stand there and hold up a 9.0 m2 rig on say a 111 liter Isonic, but you won&#39;t get it planning in < 10 knots, even with the huge rig.

I am looking for a board that will take an 8.9 / 7.4 / 6.6 and maybe a 5.5, with ????L volume and does well on a lake with 2&#39;chop and gusty wind.
The board has to plane fast, have good control, jibe well, and bring me home when the wind dies.
I&#39;d say try the Isonic 111, but I wouldn&#39;t want to sail it with an 8.9 m2 rig.
I think you may be asking for slightly more rig size range here than one board can supply.
If you put your 7.4-5.0 m2 rigs on the Isonic 111 or 105 that should work fine.
If you want to sail your 7.4-8.9 rigs, probably the 122 or 133 would be alot better.
If you want a board that handles chop well, take a look at the S-Types.
They aren&#39;t real early planers, but they handle a huge range of sail sizes and seem to cut through chop very well.
Not as fast as the Isonics, but plenty fast just the same.
It sounds like you&#39;d like to combine the attributes of your 285 and 270 into one board, and I&#39;m not sure anything other than the Isonic 111 or S-Type 115 really fits the range you are looking for.
Hope this helps,
Roger is offline   Reply With Quote