Tuesday, August 18, 2009

Starboard Tack Roundings

The HISC Wednesday night crowd has been enjoying starboard-rounding courses for the past several weeks, and a review of the rules that govern starboard tack windward mark roundings might help take some of the anxiety out of them for some people.

The simplest thing to remember is to treat a starboard-port incident at a weather mark the same as you would in the middle of the racecourse. Rule 18, the mark room rule, does not apply between boats on opposite tacks on a beat to windward [RRS18.1(a)]. So for a port tack boat who’s making the mark, ready to round, and has a starboard-tacker approaching, the port tacker has to keep clear of her, even if this requires tacking or a radical duck that might make her sail below the mark. Fortunately, knowing this means you can plan ahead on port and avoid a dramatic situation.

What about a situation between two starboard-tackers, coming in on the starboard layline, when both will need to tack? This one gets a little more interesting. The first thing to consider is if the boats are overlapped at the zone (three hull-lengths away). If they are, the outside boat, the one farthest away from the mark, has to give the other “mark room” [RRS 18.2(b)]. If they aren’t overlapped, then the boat that’s clear astern has to keep clear of the boat clear ahead. [RRS 12 and 18.2(b)].

That all sounds well and good, but something happens as soon as either boat passes head-to-wind: Rule 18 turns off. This means that as the boat in front gets to the mark, whether clear ahead or not, and begins to luff up, and then tacks, the obligations change. While luffing (heading up) she’s still clear ahead and has the right of way. As soon as she crosses head-to-wind, the Mark Room rule no longer applies. She is a tacking boat that must keep clear of a boat on a tack until she’s on her new close-hauled course (RRS 13). When she gets there, remember, she’s on port, and if the starboard tacker is close enough, she’s got big trouble.

If you’re the boat behind in this situation, you have some control regardless of whether or not you were overlapped at the Zone. If you were overlapped, you’ll get room to sail to the mark and then you can round on your proper course. But if you weren’t overlapped, yes, you must keep clear of the guy in front of you, but as soon as he crosses head-to-wind, he has to keep clear of you. If you know your boat well, and you know the other guy knows his, and you feel like something a little aggressive, try this: yell “Don’t Tack!” If he can’t tack and cross you cleanly, he’s going to break a rule, and may just wait for you to round. Just make sure you have the mainsheet out of the cleat and the boat ready to bear away if you want to make this move – he might tack anyway and you might need to turn left quick!

If you’re the boat ahead in this situation, the safest thing to do is wait until the guy behind you rounds the mark and tacks. If your competitive nature doesn’t let you just let boats go right by you, though, your options are limited by the overlap status at the Zone. If the guy behind/inside you was overlapped inside when you got to the Zone, you have to give him room to get to the mark. If he was not overlapped when you got to the Zone, you do not have to give him room, which means you can head a little higher before the mark to keep him from getting a late overlap inside you. Then, as you get to the mark, use it as a pick. Sail close to it and slowly round up as you go by, giving the guy behind no way to get his bow to weather of you and prevent you from tacking. If he’s close, and your boat tacks slowly, this might not work, and that’s fine – just pause and coast before crossing head to wind. You’re still in front with rights, and as you slow he’ll have to go outside of you, leaving you room to round.

The presence of a third or fourth boat in this scenario really makes things fun, but I won’t go into that without a specific request. Just keep n mind, most of the HISC keelboats turn slowly and roundings like this need to be planned ahead, with the crew – especially the helmsman and mainsheet trimmer – filled in on the plan ahead of time to avoid last-second crises.

Questions? Comments? Use the comment box below.

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