Tuesday, 14 October 2008

LTW Readers Q&A | 9

Answering a couple of questions from James Ricketts about hull and zone:

Q1) Is there a possible anomaly in the definitions?
- Starting, Finishing and Overlap definitions all refer to "hull and equipment in normal position" whereas the definition of Zone references "any part of hull". Is there a good reason why these aren't all aligned? It seems slightly unfair that an overtaking boat can establish rights (ie an overlap) with the end of its bow-sprit whilst a boat ahead has to sail 'further' (ie until the bow of the boat enters the zone) to deny/break such an overlap. -

A1) I think there are a couple of reasons why these are different, in my opinion.

At the zone you need to ‘guess’ when you enter. Something which is hard enough to do, even with a fixed measurement as a hull. But impossible if you add equipment like bowsprit or spinnaker into the mix. If for instance a boat with an extended bowsprit enters the zone – measured with the sprit extended – and it then retracts its bowsprit, it would be outside the zone again. A boat is x meters long. Times three is xx meters. By using the hull (that never changes) you can learn to judge that distance.

Whereas starting and finishing are very specific timed moments which are not primarily judged by the crew but by the RC. For start and finish by the people on the line, who can perfectly judge if spinnaker of bowsprit cross a certain point. No doubt or guessing involved. Overlap is something which can change any moment and has an instant effect on the rules. There, a retraction of say a bowsprit, would simply put the trailing boat clear astern. OR – like in your example – extending the sprit create an instant overlap. That is not unfair because the clear ahead boat has the protection of rule 15. With a zone entrance such protection is not available.

In my opinion it is not an anomaly but purposely differently.

Q2) What constitutes the "hull" (as in hull-length)?
- This quite key concept does not appear to be defined. I assume it is the conventional definition of the "body" of a boat (ie the bit that makes it float!), but what about bow-sprits or transom-hung rudders, or yacht push-pits? Should this be clarified in the definitions or have I missed it somewhere? -

What constitutes a “hull” is defined in the ERS section D.
If the ERS have been validated in the Class-rules, the latter only give the measurements. Olympic classes have the ERS validated in the class rules and therefore the hull is defined, all be it through a series of documents.



  1. Received an answer from James, I thought was worth sharing:


    Thanks for your clear answers which match pretty well to my own conclusions. The only further comment I'd make is with respect to the hull definition - if ISAF feel it necessary to define "Hull length" in the ERS then shouldn't it logically also be defined (or at least referenced) in the RRS?

    Whilst one could argue that the RRS explicitly suggestion that ERS should be included in Sailing Instructions satisfies this position it isn't the clearest or safest way of doing it!


  2. @James,
    Your argument is one which has been made over and over again. The problem lies in what to include in the RRS and what not. I agree that there are to many documents governing an event, but do believe ISAF is making an effort in reducing the number as much as possible. And including more and more in the RRS is not the answer.

    If all classes would use the ERS as a standard, the excess could be stemmed a little.
    But to many cling to "the old ways" and what is familiar.


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