SailNet Community - View Single Post - The Perils of Rafting On
View Single Post
  #1  
Old 08-27-2013
flandria's Avatar
flandria flandria is offline
Senior Member
 
Join Date: Jul 2012
Location: Beautiful Georgian Bay, Canada
Posts: 142
Thanks: 7
Thanked 6 Times in 5 Posts
Rep Power: 3
flandria is on a distinguished road
Send a message via Skype™ to flandria
The Perils of Rafting On

From time to time folks like rafting on, be that for social reasons or because of crowding in a anchorage. We don't like doing it, not because we are a-social, but we wish to rely on our own "rules" and discipline when anchoring. What follows is in part a cautionary tale and an opportunity to get feedback on what to prepare for when rafting. I refer to rafting that includes staying overnight.

It is an incident at the east anchorage of Beckwith Island, Georgian Bay, just this past weekend. The forecast was SW winds, 15 kts, but with a squall warning in effect that included winds potentially to 40 kts. The anchorage has an excellent sand bottom, with comfortable depths of 10-15 feet to accommodate quite a few boats. It is very easy to anchor safely there.

The incident involves two powerboats, but it may apply to sailboats as well. One vessels was about 42' and high freeboard, the second one 35' with a much lower freeboard - I estimate a 2' difference. They rafted on to each other and both put out anchors (as I learned, the boat that ended up "in trouble", anchored in 15' of water with 50' of chain/rode!!!).

Now the squall arrives, which would eventually register close to 40 kts of wind and.... it arrives NOT from the SW but from East and we are fully exposed to a fetch of at least 10NM. The chop builds up fast and soon we bounce around in 2' waves (but no more). My dinghy actually manages to disconnect itself (my fault for not having raised it into the davits - a break of my rule - but, thankfully, it is recovered on shore the next morning, firmly on the beach).

The larger power boat now is calling in an emergency: due to the difference in height between the two vessels, there is tremendous upward force on the lines at the lower boat and it starts to rip out the cleats... What to do? The skipper of that boat even falls overboard (in the dark) and injures his legs, and there is much commotion but help arrives (very quickly, to my surprise, within 30' of the call for assistance). Eventually, the squall subsides and the wind returns from the SW.

The issues I identify here - and I welcome comments - include:

1.- If you are going to raft, make sure you can accommodate wind shift. This means that you must rely on a single anchor for 2 or more boats and you must have the appropriate tackle to accommodate the extra forces that can be generated.

2.- But, avoid rafting.

3.- Be prepared to disconnect from the anchored boat quickly, because a heavy chop will indeed create damaging forces on both boats, even should they be equal in freeboard. It would be just about impossible to tie two boats together in such a way that they would move as one unit in a severe chop. This means, in fact, that you must have a plan ready to abandon the raft and anchor on your own EXACTLY when conditions will be difficult, dangerous, and (as was the case here) in darkness.

4.- Don't exprect any neighbouring boats to come to your assistance. In this case, I had no dinghy available. I also do not know how to operate a 2-engine motor boat, and all the other boats in the anchorage were sailboats.

Clearly, the skippers of both boats had not anticipated what might befall them (I, too, was surprised with the sudden change in wind direction) and showed no evidence that they had any idea what they might do under the circumstances. Since both boats had anchors out, a departing boat would have had to haul anchor in darkness and in a good chop and the crew (typically, here, the wife/partner) was likely not up to that challenge. That was a suggestion communicated to them by one of the other (sail) boats in the anchorage (leave, and motor around), but not acted on. They might have abandoned their anchor to be retrieved later, for example, given that one boat stayed behind.

In darkness I could not really see what the rescue boat ended up doing (in much moderated conditions) but after 2 hours they left, as did the smaller of the 2 boats.

As we saw the larger boat leave in the morning we noticed what looked like a good-sized, shallow dent in its starboard hull... Perhaps this episode belongs in the "boneheaded move" category - but we can all learn from others' mistakes, can't we?

Over to you...
Reply With Quote Share with Facebook