Newer theories of sailing

Some newer views on how sails work and theories behind them. Also this papers oppose many older theories.

Here are links:
Mathematichal Theory of Sailing - Johan Hoffman and Claes Johnson
The Secret of Sailing (Draft) - Claes Johnson

The Sail Consultancy web site

LM Sails have found this website with some interesting information and articles as:

Spinnaker design

Custom made upgrade to laser cutter from old rotary blade Prosail Cutter

LM Sail had posted on the forum interesting video he have found on youtube.

Unfortunately I did not found more info about this setup (components, etc.). I just know that Prosail guys did not work on this upgrade. Anyway who have time and knowledge this can be rough guide how to upgrade rotary blade to laser cutter.

Auto nesting - Prosail vs NestFab

Finally I found time to test Prosail auto-nesting module. I took Nestfab results as reference for performance judgment.

I have done three tests. The longest time I left auto-nesting to run was 10min but in practice I believe nobody will wait more then 5 mins. So below results are the best within 5 min. Only 180 degrees rotation was allowed. Test where done with 1mm (for just plotting) and 10mm (for cutting) gap between panels

First test was tri-radial genoa with fun-cut patches (66 items):

	Prosail		Prosail (pair)		Nestfab standard		Nestfab Ultra
Panel Gap	Time	Percent	Time	Percent	Time	Percent	Time	Percent
1mm	4:34	86.7%	2:09	89.7%	1:39	76.39%	1:10	90.26%
10mm	4:48	84.2%	3:51	87.3%	2:00	76.39%	1:30	87.17%

Second test was true radial gennaker with plain patches.

	Prosail		Prosail (pair)		Nestfab standard		Nestfab Ultra
Panel Gap	Time	Percent	Time	Percent	Time	Percent	Time	Percent
1mm	4:50	85%	4.19	86.2%	2:08	75.67%	1:30	90.14%
10mm	3:08	83.4%	4:28	85.8%	2:14	77.63%	1:32	88.89%

Third test was small radial patches for 36 foot mainsail (72 items).

	Prosail		Prosail (pair)		Nestfab standard		Nestfab Ultra
Panel Gap	Time	Percent	Time	Percent	Time	Percent	Time	Percent
1mm	2:26	78%	3.11	81.7%	1:00	74.65%	1:39	86.87%
10mm	2:18	70.1%	1:14	74.1%	4:32	63.6%	1:39	78.9%

Nestfab ultra is performance winner. The fastest and with the best utilization. It is well connected to modern software (SailPack and Smar-Azure) so there is no need for import/export.

Nestfab standard is not useful at all. I think that creators of Nestfab use standard version just to give you comparison dialog with ultra version. They use that as marketing tool to convince you to buy ultra option. You should take their numbers with reserve because they do not show you other calculations. For example most of the time you will manually nest panels with much better utilization then standard option within 3-5 min.

Prosail auto-nesting is sometimes performs very good (almost as Nestfab ultra) and sometimes not so good. Anyway it will always have better utilization then manual nesting within 3-4 min (and often much quicker). Pair option usually give you better results quicker but for some jobs it is not suitable as utilization will not be so good. So if you do not get 85% utilization within 3 min with pair option try without it. Maybe you will get better utilization but be aware that it will need more time.

Added on 16.05.2016:

I forgot to write that Prosail auto nesting is quite simple with just tree options:

1) Rotate panels 180 deg

2) Pair similar panels

3) Panel gap

So there are not possibility to set size of sheets (fabric), more detailed rotation, priority, ... All those options are available in Nestfab and that gives you much more flexibility with your nesting.

Switching Open Sailmakers forums to Google Group Open Sailmakers

Today I have shut down opensailmakers.org forum site (http://forum.opensailmakers.org) as it did not attract community. To spare me some time fighting with spam and maintaining the site I decided to create google group Opensailmakers with same purpose.

All professional sailmakers (and related professionals like sailcloth produces, hardware suppliers, sail-making software developers, ... ) are welcome to join group. I hope to see you there :)

Challenge Sailcloth Matrix Weaves

Recently Challenge Sailcloth announced their new style called Matrix Weaves.

Here is quote from Challenge Sailcloth announcement:

Matrix is intended for performance oriented sailors who want shape holding ability combined with enhanced strength. The cloth provides great handling and excellent durability. Matrix is a completely unique construction that utilizes DoubleBeam² technology that has added extra strength that cannot be found in other light weight sailcloth styles.

For more info can be found at http://www.challengesailcloth.com/matrix