May I ask a stupid question about my boat?

[bobbob]

I get how you measure the tension on a stay or a shroud - but how would you measure the tension on a furler?

The forestay runs within the foil on the CDI furler. It is the tension on the forestay and not the furler foil itself (which, being a solid piece would need little tension, relative to the tension on the stay, to keep it straight) that would have the greatest effect on the pointing ability of the boat, assuming the tension on the genoa or jib uphaul were correct for the sail.

I think that is what was meant by the original question.

All that also assuming you are not being facetious with the last question.

I'm not really getting it. I have a CDI furler and I'm not being facetious - is the foil the main piece that the sail rolls around? On my boat the furler *is* the forestay - is that wrong? Should I have a wire forestay as well as the furler? And if not, I still don't see how you would measure the tension on that "internal" forestay inside the furler foil?

[Highlander]

Maybe this will help u

http://www.youtube.com/watch?v=7oU2X9sAosA

J
u have a so when sailing up-wind use ur backstay to tighten up ur forestay

[seahouse]

Yes, the foil is that grey plastic extrusion with the slots in it that the sail (luff) fits into. For ease of understanding, just consider that it "floats" loosely on the stay. The forestay runs along inside that part, but the tension to keep the mast up remains borne by the forestay.

Since the top (outer) sidestays pull against the forestay and they counter each other (notice that the spreaders are aft swept, that's significant to understanding this), you don't have to directly measure the tension on the forestay to know its tension. When the sidestays are tensioned correctly the forestay tension will (approximately) therefore be correct. If you study the geometry of the rig you will see there are some inequalities in the mechanical advantage between the two, but it is part of the design of the boat.

[seahouse]

Oh yeah, just saw John's post, you have an X, so the backstay will counter the forestay as well. The X has aft-swept spreaders too I think (?)

On edit: Good video J,!

[bobbob]

Ah, I understand now! Makes perfect sense. Thanks for sticking with me It is a project this year for me to replace my existing stay adjusters with Johnson levers and really get them tight using a Loos gauge, so this is timely.

[BOAT]

Where does the backstay attach to the boat on the X model?

As for creating tack plans: it's a great math solution if your into algorithms. The shortest distance between many points is an old problem called "The Traveling Salesman Problem". You know, multiple cities, one salesman to cover them all:

For three cities the total possible combinations is like 30, for 4 cities it's like in the thousands and for 6 cities it can be millions of possible routes. The only way to find the SHORTEST is to calculate ALL OF THEM! So, that's not really an algorithm at all - Yup, "The Traveling Salesman Problem" is actually a math problem we still do not have an answer for - there IS NO algorithm for "The Traveling Salesman Problem".

GPS programs will tell you they have an algorithm for this but in reality they use a thing called 'heuristics' which means it may not really be the shortest distance. In fact, there is a Nobel award of 1 million dollars waiting for anyone that can create an algorithm for "The Traveling Salesman Problem". That's also why your car GPS takes a long time to re-calculate when you make a wrong turn.

For our purposes a tack plan would go in order from one tack to the next so there is a usable algorithm for that, and you can see it on Google or sailboat sites and stuff. It involves the same Velocity Made Good calculations that Catigale mentioned.

We all do the "seat of the pants" calculations when we drive our cars and tack our boats and even bees do it when they forage for pollen.

[Catigale]

If someone needs the solution to the TSP Im sitting on 90% of the answer, right after I prove the Goldbach conjecture.

[NiceAft]

If someone needs the solution to the TSP Im sitting on 90% of the answer, right after I prove the Goldbach conjecture.

Fine! Then figure out how to cancel the Plotnick Curse

Ray

[BOAT]

Being a gentile I can't do Plotnick, but I have solved the problem of where hilazon is hiding the Tekhelet for making things blue. He is living in the waters over here in Oceanside, but he is hiding. 'boat' found hilazon and even knows his favorite rocks offshore. Not sure how hilazon got all the way over here but some say he hitched a ride on this guy:

https://youtu.be/FEHTozrpL-I
And this is not joke! It's real and it is also right in the waters where 'boat' sails all the time!

Anyways,
If anyone knew the answer to TSP I figured it would be you Catigale, but I assure you I do not have that final 10% your looking for. I don't even have the first 50% you already have. You guys that do theoretical mathematics, conundrums, and conjectures like Goldbach always drive me crazy because I can't find practical application for Goldbach. I am a database administrator and TSP was forced on me years ago when i worked at Siemens - they needed Programmable Controller logic for the most efficient way to assemble surface electronics on circuit boards. I was clearly out of my league and the issue was promptly transferred to the brainiacs and PHD's in Erlangen.

[1st Sail]

Growing up around boats, hunting and fishing you develop a natural sense of the wind. You depend on your instincts. That said I still look at the numbers. Which brings me to the subject of a wind system. I certainly could continue sailing instinctively with no issues regarding performance, safety or just the pure enjoyment of sailing. However, when numbers are available you have the opportunity to quantify your instincts. Being able to verify you instincts quantitatively just makes them sharper. There have been times where I would get as much enjoyment honing my pointing skills with an wind system for hard stats as just sailing without.

There are several possibly affordable wind systems in the sub $1K range.
Wireless:

Sailtimer- $400, http://sailtimerwind.com/
+ blue tooth to ipad, iPhone, or compatible chart plotter (Garmin), could be rigged for trailer sailing, nav software, open source, works with rotating mast
- support for NMEA 0183 requires separate powered NMEA 0183 server, $259, no support for NMEA2000, not a lot of reviews
All in under $700

TackTick-$1000
+ wifi, NMEA 2000 compatible, separate display,
- supports rotating mast with accessory mast mounted compass, $650+
All in $1,650 mixed reviews

FlyorSail-2 models Rm-10 and RM-20 $896 http://www.flyorsail.com/
+ hard wired, separate display, supports rotating mast, NMEA 0183, Rm-20 if you want a separate display
+Rm-10 $659 less display, utilizes chart plotter wind display (if available)
-requires drilling the mast foam insert, no searchable reviews
Please add any units or comments.
Dave

[Catigale]

As someone who carried the sales bag, the TSp solution is simple....go where the money is.

[NiceAft]

As someone who carried the sales bag, the TSp solution is simple....go where the money is.

Is'nt that the truth

Ray

[BOAT]

As someone who carried the sales bag, the TSp solution is simple....go where the money is.

aft man got it right - follow the money - (Man, I was a lousy salesman - been there done that - those were dark days). Getting back to basics, in the end the only real answer to the problem I raised on this post is a wind instrument.

And I don't mean this one:



So, in that spirit I think Dan has the right to get an answer to his question:

Sailtimer- $400, http://sailtimerwind.com/
TackTick-$1000
FlyorSail-2 models Rm-10 and RM-20 $896 http://www.flyorsail.com/

Please add any units or comments.
Dave

The Sailtimer looks really good on paper but so far the only person on the site to order one has not received it yet after waiting 4 months. The reviews on the old sailtimer were not too good - apparently it's broadcast radio was not quite as strong as it needed to be for long distances. I would still hold out hope for this on MAYBE if any good reviews come in but not as my first choice.

The TicTac is a solid system that has been around for many years. There are others even better in the 3000 dollar range by B&G for the F32 and NKE makes one too - they are the legacy devices - all near 4 grand.

Pegasaus makes the best performing instrument (FlyorSail) it's a solid instrument and reviews have it out performing all others and it's also more accurate than the 3000 dollar units because it does not have the compass delay that those units have. So far it is the best unit available - I would buy it tomorrow except for one issue I have that is not the fault of Pegasus Avionics - it's my own silly preference about instruments:

I really want a wind instument with no moving parts so I can leave it on the mast when I trailer. I can't reach the top of my mast even when it's down in trailer position. I don't want to drag around a ladder to get to the mast head every time I launch the boat. I want to use an ultrasonic wind instrument like the Maretron and if Pegasus used one in their package I would buy it today. So far my favorite wind sensor is the LCJ:
http://www.lcjcapteurs.com/the-wireless ... e/?lang=en
I will probably try to figure out how to use this sensor with my boat - It would be nice if Pegasus sold a mast sensor that worked with this wind instrument.

[Baha]

Not to sound like a Luddite, but I am trying to learn to use pennants on the stays and also trying to develop a feel for the wind apeed and direction. Has worked pretty well for me so far, and the major boat bucks stay in the bank. VHS tape works great for this, btw. And

[sailboatmike]

The manufacturers of this stuff make me laugh, when you can buy a GPS (chart plotter) for your car for less than $100, yet marine chart plotters start at $400, you can buy wireless home weather stations with all the info including wind speed and direction for less than $100 yet just the wind instrument on a marine instrument is $1200 or more.

We are really being conned into paying huge prices for what is out of date technology and to add insult to injury I have heard some ridiculous refusal of warranty issues, my real favorite was a warranty claim being knocked back on a tiller pilot because it had water ingress due to a wave coming over the back of the boat, guess what its designed to sit in the cockpit (a wet environ), its IP67 rated so if built to be fit for the purpose it is sold for then water wouldnt worry it and they would honour the warranty and admit the product wasnt fit for the purpose it has been sold for,

OK Rant over