Tacking on a mark, room to keep clear?

That's a question I've been struggling with for quite some time.

Here's my best attempt at a background analysis.

In the pre-1995 RRS room for an inside overlapped boat at a mark was defined, within the room at marks and obstructions rule and included ‘space to tack or gybe when either is an integral part of the rounding or passing manoeuvre’.

Those pre-1995 RRS also provided that:

·         an inside overlapped boat approaching a mark was entitled to room to pass the mark including ‘space to tack or gybe’

·         a boat clear ahead approaching a mark that tacked to round the mark was subject to the While Tacking right of way rule and was NOT entitled to any ‘space to tack or gybe;.

The 1995 rewrite of the RRS provided a general definition of room in Definitions that did NOT include ‘space to tack’, and ‘space to tack’ was not provided in the room at marks and obstructions rule (rule 18), or elsewhere.

The 1995 RRS provided that:

·         a boat that was overlapped inside before or when reaching the two-length zone, was entitled to room to pass the mark, room as defined in Definitions and not mentioning space to tack or gybe;

·         a boat that was clear ahead when she reached the two-length zone remained the right of way boat even if an overlap is established later, but if she tacked she ceased to have right of way and rule 13 applied.

 

Seemingly the intention to privilege an inside overlapped boat, over one clear ahead was preserved and the 1995 drafters thought that room to pass the mark included room to tack without saying so.

Cases 15 and 81, decided in 1966 and 1983, about mark-room switching off in a tack, both concerned a boat clear ahead tacking, so were not inconsistent with this view.  Case 95 was not decided until 2000.

 

The 2005 rewrite of the RRS introduced the defined term mark-room and the three length zone.  All mention of right of way boat with respect to mark-room was deleted, so that rule 18 only dealt with obligations to give mark-room, and no depended on or changed any right of way obligations, reconciling Section A right of way breaches with mark-room breaches by means of the exoneration mechanism.

The definition of mark-room re-introduced the issue of whether mark-room included room to tack by saying ‘mark-room does not include room to tack unless the boat is overlapped to windward and on the inside of the boat required to give mark-room’.

This bespeaks an intention to maintain the privilege accorded to an inside overlapped boat, but note the ‘back-handed’ wording stating what mark-room does not include.

These changes are consistent with the current wording of the rules.

In my opinion, whatever the intention of the drafters of the rules may have been, according any form of mark-room to a boat, once she has passed head to wind is outright contrary to rule 18.1, which disapplies the whole of rule 18 to a boat that passes head to wind, as confirmed by Case 95.  The negative formulation of the reference to room to tack in the Definition of mark-room is completely insufficient to displace the plain words of rule 18.1 and Case 95.

I found this in the 200 where you if you were clear ahead the boat would need to be really close behind for you not to be able to complete the tack and give them room to avoid. So you could just do a slow head up in to the tack, giving away 1/4 of a boat length to force them outside. If they're further back than that you can probably get your tack in and give them room to keep clear.   

But, in the 800 when you're reaching in on a fat lay at 12 knots and when you stop so much in a tack you feel quite vulnerable. Typically you'll slow to 2-3 knots and it'll take 1-2 second to go from head to wind to close hauled. A boat chasing in on the lay could be two boats lengths clear astern and still get a piece of you whilst tacking. Slowing down two boat lengths within a 3 boat length zone isn't a subtle manoeuvre and slowing down that much before a tack is a recipe for getting stuck in irons. So you effectively end up giving mark rounding position back to a boat 2 boats lengths clear astern for fear of breaking rule 13 or 15.  

Really, the boat clear astern should be able to pre-empt you tacking and avoid you in a similar way as they can pre-empt a gybe drop at a leeward mark and the closing speeds are even greater there. It's not like half way up the beat where they will have no idea you are about to make a significant course change and need the protection of rule 13, 15 and 16 to give them room to keep clear. Rule 18 specifically turns off those rules for roundings anyway? 

Thank you for the history. 

18.1 turning off rule 18 for boats on opposite tacks on a beat makes complete sense. It stops port boats coming in on the layline. I know that happens at leeward marks, but there starboard boats can just bear away a little to afford room. Up wind they cannot head up without stopping and causing a pile up.  

However, the way it's worded seems to have some strange implications for boats reaching in to mark they shall tack around. 

18.1 a) specifically makes the opposite tacks exemption for boats on a beat to windward... but then 18.1 b) seems to make opposite tacks exempt all the time.  

Does the diagram below change your rules interpretation? And if not, then what is the purpose of rule 18.1a)?