wrote in message
...
On Oct 16, 3:24 am, "Roger Long" wrote:
...
My best guess at this point would be misjudgement by SB due to the size
of
MR combined with a desire to make a close pass. The degree of stern
swing
in a turn of a vessel that large will enormous compared to what the SB
operator might expect thinking of her as a "sailboat". A vessel of that
size is of necessity rather shoal in proportion to length. Turning from a
reach to close hauled, it will take a while to accellerate to a speed
where
the underbody is fully effective and there will be a few boat lengths of
greater leeway. ...

Well, my ship handling "knowledge" at the 290' scale is the tiny bit
of theory I read for my license and I may be standing up a bit for the
underdog on principle. Still, I have this feeling that if, as stated
by Perkins the vessels were on reciprocal courses with MF slightly to
weather just before the incident then MF's turn to port could the
primary cause of the collision.

Given that:
1) the frames are 3 seconds apart
2) reciprocal courses
3) MF is 290' long
4) MF pivots about her keel more or less at 145'
5) MF turned port 30 to 45 degrees between frames

I think if follows that:
1) CPA closed 75-100 feet in 3 seconds because of MF's course change
2) the stern of MF was suddenly moving ~15 knots faster towards SB
than it was before the start of MF turn

Now, MF claims that they were going to pass to weather of SB on the
courses they were both on and that they made their turn to open the
CPA to 200'. I take that to mean that they had a CPA of less than
200' and from the photos the turn they took was big so the CPA must
have been a good deal less than that. From SB's point of view the
stern of MF suddenly comes across their bows and the speed of closure
is roughly doubled and CPA was reduced 75 to 100'. SB is stand on.
It is clear that SB luffed her sails w/in the 3 seconds the MF began
her turn and they remained eased for the entire sequence. SB is
attempting to avoid a collision but can she? MF's stern is coming at
her in excess of 15 knots so going astern of MF is suddenly
impossible. MF's midships is still closing at MF's leeway plus SB
forward motions (say 10 knots). A crash tack may be the best bet but
even that might not be enough but the 27 seconds from MF's alteration
to crash doesn't give them much time to think about it.

Conclusion is a little strong but I suspect:
1) if MF had not altered SB would have passed safe astern of her
2) MF made a major change of course seconds before contact in
violation of Rule 8
3) SB was stand on but in extrimis attempted to avoid contact
4) MF was obligated to give way and do so with ample time.

Therefore MF is primarily at fault. While SB should have taken more
decisive action when it was clear that a collision was imminent and
certainly should have stood by after the crash she is largely
innocent.

Your witness

--Tom.

All your guesses mean NOTHING. Both boats were at fault as neither boat took
action to avoid a close quarters situation. Both captains were asleep at the
wheel and negligent.


RULE 7

Risk of Collision

(a) Every vessel shall use all available means appropriate to the prevailing
circumstances and conditions to determine if risk of collision exists. If
there is any doubt such risk shall be deemed to exist.

(b) Proper use shall be made of radar equipment if fitted and operational,
including long-range scanning to obtain early warning of risk of collision
and radar plotting or equivalent systematic observation of detected objects.

(c) Assumptions shall not be made on the basis of scanty information,
especially scanty radar information.

(d) In determining if risk of collision exists the following considerations
shall be among those taken into account:

(i) such risk shall be deemed to exist if the compass bearing of an
approaching vessel does not appreciably change;

(ii) such risk may sometimes exist even when an appreciable bearing change
is evident, particularly when approaching a very large vessel or a tow or
when approaching a vessel at close range.


RULE 8

Action to Avoid Collision

(a) Any action taken to avoid collision shall, if the circumstances of the
case admit, be positive, made in ample time and with due regard to the
observance of good seamanship.

(b) Any alteration of course or speed to avoid collision shall, if the
circumstances of the case admit, be large enough to be readily apparent to
another vessel observing visually or by radar; a succession of small
alterations of course or speed should be avoided.

(c) If there is sufficient sea room, alteration of course alone may be the
most effective action to avoid a close-quarters situation provided that it
is made in good time, is substantial and does not result in another
close-quarters situation.

(d) Action taken to avoid collision with another vessel shall be such as to
result in passing at a safe distance. The effectiveness of the action shall
be carefully checked until the other vessel is finally past and clear.

(e) If necessary to avoid collision or allow more time to assess the
situation, a vessel shall slacken her speed or take all way off by stopping
or reversing her means of propulsion.

(f)
(i) A vessel which, by any of these rules, is required not to impede the
passage or safe passage of another vessel shall, when required by the
circumstances of the case, take early action to allow sufficient sea room
for the safe passage of the other vessel.
(ii) A vessel required not to impede the passage or safe passage of another
vessel is not relieved of this obligation if approaching the other vessel so
as to involve risk of collision and shall, when taking action, have full
regard to the action which may be required by the rules of this part.
(iii) A vessel, the passage of which is not to be impeded remains fully
obliged to comply with the rules of this part when the two vessels are
approaching one another so as to involve risk of collision.

I hope this helps.

Wilbur Hubbard