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The inverted 'P' course

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Do you like the inverted 'P' course?

YES
9
53%
NO
8
47%
 
Total votes: 17

George Stephen
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Inverted P Queries

Post by George Stephen »

Hi Andrew,

I guess you've probably been unlucky to have sailed only at events where the P course has been poorly set, when the leading boats spotted which is the best route and everyone with any sense followed them, UNLESS they could see that the wind had shifted to favour another option, or that the disadvantage of the favoured route might be out weighed by avoiding a poor rounding situation at the leeward gate and dirty air on the beat. If the course had been properly set, then you would have seen boats splitting at the P mark (some gybing onto starboard to round the pin 4P, others staying on port to round the committee boat 4S) and splitting through the leeward gate. And it would have been up to you to decide which was going to be best for you - conditions might have changed just that tiny bit from when the boats ahead made their choices!

So here's my answers - Bob probably put it more succinctly....

Your 1) Is it true the leward gate, the starting line, the 2nd P mark, and the windward mark, are all placed directly in a straight line with each other?
Ans 1) YES, it is critical for the leeward gate, start/finish line (as shortened from the usually longer length used for the Start) and the P mark (what do mean the 2nd P mark? There's a windward mark 1P, a wing mark 2P, the P mark 3S, the committee boat 4S OR the pin 4P, the leeward gate marks 5P OR 5S and the start finish line 6 - with P denoting leave to port etc) to be directly in line with the wind direction. AND the ends of the start/finish line 4S and 4P and the 2 leeward gate marks 5S and 5P must be equidistant with a line drawn through the P mark downwind. Only then do helms have genuine choices as to which options to take, because otherwise one particular route through is bound to be quickest! If you have doubts, draw a properly set chart of the relevant marks and the courses, including beating angles at, say, 45 degrees. Then pencil in a poorly laid mark and the courses that could be followed - compared to the properly set marks it should be easy to see on paper which route should be quickest. Repeat until you've tried out moving the P mark 3S left and right, too long a finish line 4P, and moving one of the leeward gate marks in, out, upwind and downwind, and upwind and downwind from in and out positions. Don't bother with moving the other leeward gate mark or the committee boat - unless you can't imagine the mirror image effect! Ironically, as long as the windward mark 1P is more or less dead up wind from the start/finish line, a little error is hardly going to matter to most helms.

Your 2) Do sailors ever confuse the 2nd 'P' mark for the windward mark?
Ans 2) Not usually, because they usually know that the P mark 3S comes first, and the windward mark 1P will be further on, and that's the one they beat to.

Your 3) Should the 1st 'P' mark be placed precisely at right angles to the windward mark? And how tight should our reach be to the 2nd 'P' mark?
Ans 3) It seems usual for one of the reaches to be close to a beam reach (usually more off wind than close), and the other to be a broader reach (but NOT so broad that we can't fetch from mark to mark on a genuine reach, rather than an angled run!). The order is not material, but there is something to be said for the first reach from the windward mark to be broader, making it less likely that helms can "erl" their boat into an inside overlap when previously clear astern and cause mayhem, collisions of the nasty T-bone variety, etc.

I hope this helps,
George 1594
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Bob Carter
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Post by Bob Carter »

Bob Carter wrote:Hi Guys.

The reason why we have the inverse 'P' course is variety.

As a fleet we do not like the old fasioned Olympic Course (triangle, sausage, etc) as the reaches are too broad and the sausage involves a long run which is not very tactical with just one sail when you can go straight downwind. It is also less good for the heavyweights who tend to wallow on the downwind leg. We also do not like upwind-downwind courses which are popular with the asymmetric classes for the same reason.

The square or trapezoidal course is universally popular because we get tighter reaches and less downwind (for the trapezoidal).

The inverse 'P' course has exactly the same advantages as a trapezoidal course as it offers tighter reaches than a trangle and a lower proportion of running than an Olympic. So it offers us an alternative course. It would be a boring life if we did squares or trapezoidal courses all the time.

At the Nationals we generally use a downwind gate with the inverse 'P' course and also prevent the competitors from sailing through the start/finish line in the downwind direction. This presents the sailors with 2 tactical alternatives (which end of the line to go around and which of the 2 leeward marks to round). This tends to be a test of skill and judgement and breaks up the procession on a well set course.

The one disadvantage is that the region between the start finsh line and the 2 leeward marks can get busy/ congested and we have had some collisions, especially down at the novice end of the fleet. This has been worst when there has been a strong wind (when things happen fast) and we have been tight for space (e.g. at Grafham in 2003). For this reason for the last couple of years we have mostly used the square course when the wind was strong and we have not been too constrained for space.

At Netley I came to the conclusion that we should have a 3rd course option for sailing in a narrow estuary which would change the order in which the legs of an inverse 'P' course were sailed such that the course becomes a 'd' course. Thus we would beat to mark 1, run to mark 2, reach to the wing mark 3, reach to the leeward mark 4 and then beat through the line. The advantage of this would have been that we would have had better reaching angles on day 3 at Netley where the first reach of an inverse 'P' course was very broad and long. It has a couple of disadvantages - the boats going onto the run at the windward mark impede those approaching he mark on port tack and there is not the option of a downwind gate. I do not plan to add this option to the sailing instructions until we next sail in a congested piece of water.
Cheers
Bob
What are the views on the suggested 3rd optional course ("d") since we return to Netley this year?
Cheers
Bob
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Post by Andrew Hannah »

Hi Bob,

Being in the lower third of the fleet, I don't like the leward gate. So the "d" course has posibilities. I still think squares are best.

On the question of a "d", one possibility is to have a spreader mark about 100 yards to the left of the windward mark. This would help prevent boats colliding at the bear-away.
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ALternative Courses at Standard Nationals

Post by George Stephen »

Hi Bob,

Given the constricted waters at Netley, a trapezoid course is probably only viable when the wind is roughly along or at right angles to Southampton water. I think you're spot on on having alternative courses specified for when the wind doesn't fit. But a "d" doesn't cover the situation where the wind is roughly due north or due south, when a "9" or a "b" might be needed. (Arguably, a "p" might be better than a "d" sometimes, but as it would mean starboard rounding at the windward mark I'd prefer it be avoided.)

I support Andrew's suggestion of a spreader mark, but I think it could be less than 100m from the windward mark - which might be necessary at Netley?

I'd make one further comment on the use of a "d", "b" or "9" course - I think it's better if the start-finish line is on that part of windward leg of the course when downwind boats are reaching to or from the wing mark, as collisions are less likely due to reduced "crossing". If the start-finish line has to be across the "downwind" leg, I'd make the start-finish line an obstruction downwind (given the limited sailing area at Netley, this might be the least worst option).

It was at Netley that the RO set the worst Inverted P course I have sailed, due to the inaccurate relative positioning of the P Mark, the Start-Finish Line and the leeward gate marks. Even worse was the fact that the RO could see the lack of real options for helms (most boats took the same route each lap) and did nothing between races to improve the positioning of the marks. I'd be concerned if the Inverted P course was an option at this venue.
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Bob Carter
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Re: ALternative Courses at Standard Nationals

Post by Bob Carter »

George Stephen wrote:Hi Bob,

Given the constricted waters at Netley, a trapezoid course is probably only viable when the wind is roughly along or at right angles to Southampton water. I think you're spot on on having alternative courses specified for when the wind doesn't fit. But a "d" doesn't cover the situation where the wind is roughly due north or due south, when a "9" or a "b" might be needed. (Arguably, a "p" might be better than a "d" sometimes, but as it would mean starboard rounding at the windward mark I'd prefer it be avoided.)

I support Andrew's suggestion of a spreader mark, but I think it could be less than 100m from the windward mark - which might be necessary at Netley?

I'd make one further comment on the use of a "d", "b" or "9" course - I think it's better if the start-finish line is on that part of windward leg of the course when downwind boats are reaching to or from the wing mark, as collisions are less likely due to reduced "crossing". If the start-finish line has to be across the "downwind" leg, I'd make the start-finish line an obstruction downwind (given the limited sailing area at Netley, this might be the least worst option).

It was at Netley that the RO set the worst Inverted P course I have sailed, due to the inaccurate relative positioning of the P Mark, the Start-Finish Line and the leeward gate marks. Even worse was the fact that the RO could see the lack of real options for helms (most boats took the same route each lap) and did nothing between races to improve the positioning of the marks. I'd be concerned if the Inverted P course was an option at this venue.
Hi George,
Thanks for your comments. Yes - the last Netley Nationals did not do a good job of setting the inverse P course, but after a difficult practice race I warmed to the Race Officer (David Henshall) who tried very hard to please us. Part of the problem was that the course did not fit the bit of water as the beat took us right across to the shipping channel as there was no room for a reach - it was virtually a run. This would not have been the case if the angle of the wind had been 30 degees more to the east so that the windward mark was near the shore by Western Sailing Club - we could then have had our first reach tight across to the shipping channel and it would have worked well. It is also true that not enought attention was paid to tactical options around mark 3 the start/finish line and the leeward gate. These just need to set true so that there are fairly equal options available.

The 'd' course I am proposing deals with the wind direction we got on day 3 - I agree with the addition of a spacer mark near the windward mark. Your suggestion on a 'b'course would apply to the same wind direction that is satisfied by the existing inverse 'P' course.

The proposal was to add one extra course (making 3) to deal with a problem wind direction. These courses are in my view optional depending on the wind direction, strength and the shape of the water available. Not all need to be used but it is nice for the race officer to have options available. We do not want to confuse people by having too many options but 3 seems workabe to me.
Cheers
Bob
Last edited by Bob Carter on Thu Jun 03, 2010 1:18 pm, edited 1 time in total.
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Robert
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Re: ALternative Courses at Standard Nationals

Post by Robert »

Bob Carter wrote:I agree with the addition of a spacer mark near the windward mark.
If there is one of those, can you make it really big with a flashing light on the top, please? I tend to not notice them when looking for the next mark some distance away. :oops:
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Post by Charles »

I'm with Gordon & Bob on this, Pwllheli was a superb course & inverse P should be used for variety & tactics, but not in strong winds. A gate at the leward mark makes for much more thinking, rather than playing follow-my-leader.

If I've got a spare evening during the Nationals I'll ask George to talk me through his comments, as I lost track after the 3rd paragraph!
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Post by George Stephen »

Bob,

I agree that the Inverted P course that we have used at the Standard Nationals would fit with a northerly/southerly wind. But I'm not sure after our previous experience at Netley that we can expect them to set it up properly - and Netley's restricted sailing area suggests that it could never be as good as it was at Pwllheli.

An inverted P without the leeward gate was what I had in mind when I suggested a "9".


George
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Post by Mark Aldridge »

I remember 2003 @ Grafham. Fortunately (for me) it was windy and I was having a reasonable day at the office nearer the front of the fleet.

The leeward buoys were quite close to the shore and that gave little space... The subsequent boat damage was significant and yes it should not have been set.

However and as mentioned above, if there's the space and it's safe then why not have a bit of variety. Makes you think about what you're doing (not something I can usually be accued of!)..

It's the same for us all and is one alternative...
Mark Aldridge
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