Velocity Made Good (VMG) - Definition, Examples, Target Boat Speed
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- เผยแพร่เมื่อ 7 มิ.ย. 2024
- Welcome to another SailZing.com tutorial video. In these videos we explain sailing concepts simply and visually, and show you how to apply them.
The video discusses velocity made good or VMG. Many newer sailors are not familiar with this important concept, so we take a moment to go through the definition and show some examples. Then we talk about how to use the concept of target boat speed to maximize your VMG.
See our video on Ladder Rungs for related content: • Ladder rungs
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Thank you for this video on VMG.
Great video. Thank you.
In a lull while going upwind, bleeding speed by pinching or even luffing a bit works like a champ just like you mentioned when going downwind.
Helpful, thank you!
Best explanation ever! After looking at 6 other channels VMG videos, I must say yours is the simplest and clearest of them all. Now I must find your vid about "ladder rungs?" to learn more tricks. Thanks from an old sailor who never had electronics onboard. Subscribed.
Wow, thanks!
Well explained, thank you
You're welcome!
Can you please explain me what is the CMG and the difference between VMG and SMG? Many thanks
Good explanation! However I'm not sure about how I should think in case there is a wind shift. Let me give you an example:
Let's say we have two boats, A and B. They are both sailing close to each other at the port tack and at Best VMG. Now a right shift comes in and both boats are in a header. To compensate for this shift boat A just continues on port side but have to fall off to keep the same optimal speed (Best VMG?). Boat B tacks to starboard and will be lifted. The further boat A continues on port tack the more distance to the windward mark he will loose.
So does boat A and B have the same VMG after the wind shift or does boat B have a better VMG?
VMG is defined in relation to the wind. There's another term, VMC (velocity made to course), that is more appropriate when the wind has shifted and is not straight down the course. After the shift, B gets on the lifted tack and has better VMC than A. If you want apply the term VMG to the situation described, you have to choose whether you measure it against the actual wind at the time or to some other measure such as the average wind. if you measure it against the actual wind, then both A and B could be maximizing their VMG. Interestingly, there's a technique called Wallying in which you pinch if/when you have to sail in a header and foot slightly when you're in a lift. This maximizes the VMG to the average wind. We'll write an article on this eventually, but you could search for the term on the internet in the meantime.
@@SailZing Ok, thank you! I didn't know about the term VMC, but that explains it all. What actually got me thinking was this (I don't remember the exact phrasing, but it was something similar to this) - "The boat that has the best average VMG will always win the race". That can't be true if we're talking about VMG. You can sail at the best VMG the whole race, but if you keep missing the wind shifts you will still lose the race even though you had the best average VMG in the fleet. Or am I still missing something here?
@@BennyLindstedt71 If you define VMG in relation to the average wind direction, then the statement is true.
An important question, i need a physics answer. In the case that vgm is parallel to the the wind Is it possible that the value of VGM is bigger than the value of the wind?
no.
Many thanks for the answer, after much research you are the first to confirm that it is not possible to have a VGM greater than the wind. Sorry for the redundancy of the question, I ask you for a reinforcement, your answer is also valid in case of downwind right?
Do you know if there are textbooks where you can study the physics of this topic?
And what about wally tactics? (More important than vmg? :) )
Good question. We're looking to do an article about "Wally" in the future.
@@SailZing
Oooo. What a quick answer)))
However, try to preempt the video by answering the following questions:
1. Is 'vmg tactics' part of 'wally tactics' or vice versa?
2. Which of the yachts is better adapted to wt - Laser or 49er? Is it relevant on Optimist?
3. In what leg wt is more effective - upwind or downwind?
4. In what wind condition should we use wt?
5. There is an opinion (even among top racers) that wt gives a negligible advantage and even - tactics are speculative, far-fetched. Is that so?
6. By the way, I met the term 'bow down' in your videos (Roble/Shea Sailing).
Is that Wally?
@@MikleM1 Thanks. We'll look into these areas. There's some data out there but not a lot. "Bow down" simply means to foot a little, not necessarily for the purpose of wallying.