I liked the Velocitech Prostart I got to use on my J/80. Andy Andrew Burton 139 Tuckerman Ave Middletown, RI USA 02842
www.burtonsailing.com http://sites.google.com/site/andrewburtonyachtservices/ +401 965-5260 > On Dec 19, 2019, at 13:43, John Conklin via CnC-List <cnc-list@cnc-list.com> > wrote: > > Wowza ! Nice rant :) lol š > Crazy !! You just canāt make that stuff up! > On another note how do you like the TackTick considering this for Christmas > request from Mrs Claus as I can use on both the C&C and the Etchells ! :) > > John Conklin > S/V Halcyon > >> On Dec 19, 2019, at 12:04 PM, David Knecht via CnC-List >> <cnc-list@cnc-list.com> wrote: >> >> ļ»æ So you poked something I wasted too much time on so I am going to waste >> more time venting about Sailtimer: >> >> I have no experience with their hardware, but I was considering purchasing >> the wind instrument. It looks like an interesting piece of hardware, and I >> was concerned about my TackTick wireless wind sensor being 7 years old. I >> sent the Tacktick to Raymarine and they checked it out and found it good as >> new, so I donāt plan to āupgradeā. In the process, I had many emails with >> Sailtimer regarding how the app worked, because I am a very data driven >> racer, and it looked like it might provide some interesting/useful data. I >> found them to be condescending, obtuse, ignorant, confusing and many other >> adjectives that I wonāt repeat. I tried very hard to get them to explain >> how their algorithm dealt with wind shifts (my primary concern for a wind >> sensor) and while I think I finally got them to agree that wind shifts are >> important in racing, I still have no idea what the software provides in >> terms of useful data on upwind performance and shifts. It seems like it >> might give you some data on how to steer relative to polars, but I am not >> sure how useful the implementation is in the real world. I donāt think it >> provides anything useful on wind shifts. Here is a sample of the kind of >> gobbledygook I received: >> >>>> Headers and lifts are actually another antiquated racing method, that are >>>> very clumsy in the age of GPS and computers. They were great in the 1920s >>>> when it was impossible to do trigonometry every second in a boat heeled >>>> over and crashing through waves. But they make you choose some arbitrary >>>> length of time to get an average wind direction. And they make an >>>> assumption that the wind is going to go back to average later. If a lift >>>> happens for 2 minutes, why call that a lift and not say that it is the >>>> real wind? Too many assumptions. >> >> I disagree. The decision of whether a shift is 2 min or 10 min or 10 >> seconds is a key decision a racer makes and calling them right is what wins >> races. They seem to think it is unimportant. I sent them a pdf that showed >> why you sailed lifts and not headers to shorten the distance to the weather >> mark. I got this in response: >> >> This again is an oversimplification. All sailors know that you cannot >> simply shorten the distance (otherwise you would try to go at 2 knots nearly >> straight upwind). (DAK: in fact all racers know that what they say here is >> wrong. This is not about trying to pinch to go straight to the mark. This >> is about sailing lifts to shorten the distance while sailing optimal on each >> tack. This is ABSOLUTELY about shortening the distance to the mark!) To get >> to the mark fastest, the optimal tack is a balance of minimizing tacking >> distance (no idea what that means) and getting the fastest boat speed from >> the polar plots. The SailTimer app recalculates all of this every second (I >> agree sailing fast to polars is important, but it cannot determine the >> shortest distance if it cannot decide what is a lift or header and what is >> not. I would want a historical (for the race) perspective on the wind angle >> was 2 min ago or when I last was on that tack). >> >> This is just geometry and vectors really; there is no reason to use your >> grandfatherās old shortcuts and rules of thumb, when there is a powerful >> computer and live GPS and wind data on any smartphone now. :-) >> >> Also, many of the rules in the PDF are for artificial race courses, but they >> do not work if the mark is not exactly upwind (DAK: untrue! Sailing lifts >> and not headers works whether the mark is directly upwind or not! It only >> changes the laylines and how far you are going to sail on each tack.). But >> the SailTimer app calculates optimal tack headings on all points of sail. >> It is also the only product that uses tacking distances (undefined) to >> calculate the optimal course (no idea what that means). >> >> On another point: they claim that there is an optimal set of tacks to the >> weather mark which their app calculates in advance and then updates as you >> sail (you can see an example on their web site). I contend that there are >> an infinite number of tack combinations that would get you to the mark at >> exactly the same time if nothing changes during the leg. The optimal set of >> tacks in a race is actually a complex combination of current, shifts, >> competitor positions, land masses, tides, obstacles etc. and the software >> cannot/does not determine that. They are also very confused about optimal >> course on a tack (polar performance) and when you change to the other tack >> (port starboard). They use the same term for both making explanations >> incomprehensible. >> >> Bottom line: the hardware might be fine, but I would not expect much from >> the software. I would be interested to hear from anyone who uses the >> software to know if it is better than their ability to explain it. Dave >> >> S/V Aries >> 1990 C&C 34+ >> New London, CT >> >> <pastedGraphic.tiff> >> >>> On Dec 18, 2019, at 9:55 PM, Randy Stafford via CnC-List >>> <cnc-list@cnc-list.com> wrote: >>> >>> Listers- >>> >>> Have any of you used products from SailTimer, e.g. their SailTimer App and >>> SailTimer Wind Instrument? If so, Iād appreciate hearing about your >>> experiences with the products and the company. >>> >>> The company is based in Halifax, Nova Scotia, and headed by Craig Summers. >>> Anybody on this list know him, or other employees of the company? >>> >>> Thank You, >>> Randy Stafford >>> S/V Grenadine >>> C&C 30 MK I #79 >>> Ken Caryl, CO >>> _______________________________________________ >>> >>> Thanks everyone for supporting this list with your contributions. Each and >>> every one is greatly appreciated. If you want to support the list - use >>> PayPal to send contribution -- https://www.paypal.me/stumurray >>> >> >> _______________________________________________ >> >> Thanks everyone for supporting this list with your contributions. Each and >> every one is greatly appreciated. If you want to support the list - use >> PayPal to send contribution -- https://www.paypal.me/stumurray >> > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each and > every one is greatly appreciated. If you want to support the list - use > PayPal to send contribution -- https://www.paypal.me/stumurray >
_______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
