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9/04/2020 10:47 pm  #1


Minimum time for sail change

We do a lot of “around the islands” shorthanded racing on “complex” courses with many legs in all directions  - is there any way to add a setting for “minimum time on sail“? We often se “suggested” sails in both optimum routing and the route table for actual conditions suggesting sail changes for distances at <0.1 Nm. Sailing shorthanded these changes are just not justifiable - a setting similar to penalties for tacks and gybes that takes these suggestions out of the route table would help a lot in getting that super overall insight in to the upcoming sail changes - especially as the wind shifts and everything changes :-)

 

9/05/2020 12:04 am  #2


Re: Minimum time for sail change

I vote for that feature too - something like a minutes average so any optimum changes gets averaged out - this way if you are using a display showing optimum sail you have confidence that the one being displayed is the long term average optimum

 

9/05/2020 12:58 pm  #3


Re: Minimum time for sail change

My philosophy is slightly different. I would prefer to have the information there and just ignore/use the items I wish.

With the KND style sail chart, you get multiple sail options too.

 

9/07/2020 1:02 am  #4


Re: Minimum time for sail change

Nick wrote:

My philosophy is slightly different. I would prefer to have the information there and just ignore/use the items I wish.

With the KND style sail chart, you get multiple sail options too.

 
This is a simple example of what I'm trying to avoid, you can see I'm on J4 and eventually have an upcoming change to J2 as I’m rounding this small island and later a slight change in heading will allow for my Asymmetric.  However as I’m rounding a small island – I have a 36 second downwind leg with S2 recommended.
 


As the wind shifts I’m trying to check it the upcoming Asymmetric leg opens up to allow for S2 … what  I’m trying to achieve is to “declutter” the 36 seconds S2 sail change from the table to make sure I’m not misreading the table thinking the longer leg is now S2 (being stressed sailing shorthanded on a tight inshore course).
 
But if the change is the other way around long S2 – short J4 – long S2 with a short beat to windward in between downwind legs, similar to this example



I would definitely like to see and plan for the sail change – so I’m guessing this might only apply to short downwind sail changes.
 
I will try and play around with the KND style sail chart and see what it would look like.

     Thread Starter
 

9/08/2020 2:34 am  #5


Re: Minimum time for sail change

I have a similar view to Nick, that if you put in a very short leg you should be aware of it and consider the time given alongside the sail selection from your XO chart lookup, in much the same way that you would have to consider the wind bends around an island feature and what the implications would be to that potential sail change timing.


:::Campbell Field::::::www.fieldyachting.com:::
 

9/08/2020 4:56 am  #6


Re: Minimum time for sail change

Surely the table is an aid to  make a decision rather than something to fully rely on, my suggestion was only an option to set some simple rules for some of these considerations -  but I realize it´s more complex than I first thought, 

Long down wind - short up wind - long down wind
Long up wind - short down wind - long up wind
Long down wind - short down wind - long down wind
Long up wind - short down wind - long down wind
Long down wind - short down wind - long up wind

Would all need to be treated differently and with a large sail inventory this could get rather complex - I guess a smart choice could be automated, but it would most likely require a lot of data on each sail..

So perhaps - I just need to be more focused reading the table  

     Thread Starter
 

9/08/2020 1:30 pm  #7


Re: Minimum time for sail change

Fred, I'm with Nick and Campbell, I think you are over-thinking this.
Figure out how long the next leg is, and how long it takes to change from one sail to another and back again (think say 50% BSP for the changes and loss of concentration).  Your first mental calc will give you the right answer nearly all the time.
Big sail inventories muddy clear thinking, and mostly require rationalisation.  If more than one sail gives 100% performance most of the time, which has the smaller 100% range?  On the dock with it.

 

9/08/2020 3:23 pm  #8


Re: Minimum time for sail change

It all works well Nick. There is no need to over complicate this. The job of the navigator is to interpret information. My vote is to leave as is.

 

9/09/2020 4:49 am  #9


Re: Minimum time for sail change

It was only a suggestion for an extra feature 😊 my idea wasn't to change anything for anyone that would like to see everything.

But as I said earlier - I did not initially realize how complex it would be - I was thinking a simple optional input of time as a “filter” and thought it could be a simple feature to add, and also one that would change nothing unless a value was entered. With a better understanding of the complexity - I'm sure time developing could be spend better!

I agree the route table works great, I use it all the time and I'm totally fine with the way it is 😊

I recently sailed a shorthanded +100 boats and +24 hours day and night race with over 75 marks to round inshore ... most of the time spend navigating is really about avoiding shallow areas (our 2,5m draft is a lot in our area) - so the less time I spend thinking about upcoming sail changes - the more time I have to keep sails properly trimmed, respond luffing competitors, avoiding land, keeping an eye out for competitors in the dark and everything else that needs to be done - but I can see this is a bit of an extreme case ... I will keep reading the table and make decisions based on all the information at hand 😊



 
 
 

     Thread Starter
 

9/09/2020 8:38 am  #10


Re: Minimum time for sail change

I think you just have to make the call even short handed. I always feel the more information you have the better.
For example you can't hold a kite no matter how short a time if you need to go upwind. (yes you can do things to rag the kite or gather the foot depending on conditions/size)
You may recommend staying on a reaching sail to get as much height as possible if you have to use it for a short leg before going to a deeper kite if the leg after requires a deep running kite rather than 3 sail changes -- but you need all the info to make the call. Hiding information just makes that call harder to make.

 

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