Berthing with Less than Adequate Draft at Low Tide

[waterside]

Hi There,

Does anone have any thoughts on berthing a fin keel yacht with a foot less at low tide than the draft of the yacht?

I am looking at sailing to Paunui coromandle (new zealand) from Auckland, we are wanting to park up for a couple of nights over new years, there is a berth available but is 1.5m deep at low tide to my 1.8 draft. mud bottom.

There are not really a lot on anchroring options their in deeper water as it is very tidal and I'd like an option to weather any large widnds that may crop up.

Am I stupid to consider or do people do this?

[skipmac]

If the bottom is mud only, soft deep mud, no rocks, no hard bottom AND the slip will not be subject to any waves or wakes at all then, yes I would consider it.

[waterside]

Thanks for the quick reply, yes its very sheltered no wake area. (housing with boat ramps and pontoons)

I suspect it will sink in the last foot anyway rather than lean over.

[skipmac]

The only other thing to consider, make sure you are well tied to a sturdy dock, just in case the boat starts tipping over.

[waterside]

Yes, I'd defnitely have to check it out beforfe hand, from what I can see there are pontoons with piles, I could tie off to the piles allowing for tide.

[Arch Stanton]

Not practical for a 3-day stay, but there's a guy in my sailing club with an O'Day 27 that keeps it moored in a hole in a mudflat that (I'm told) he maintains quarterly with a pump and a hose. He can come and go as he pleases in a +6' or higher.

[waterside]

Nice! there must be huge tide there.
I spoke to one of the local contractors down there he said they can dig it out if need be but at a cost of $800 worth it if I was going to use it more regulally but for a couple of nights thats a bit excessive.

[Bash]

Originally Posted by waterside

Am I stupid to consider or do people do this?

I've done it more often than I'd care to repeat. It can be tough on bottom paint, but otherwise I've never been damaged.

A few thoughts: First, when a harbormaster says you've got 1.5 meters at low tide, take that with a grain of salt. Sometimes this means that the harbor was once dredged to that depth, but if it's been years since the last dredging, there could be significantly less water in the slip now.

Second, there's mud and then there's mud. A couple nights in silt probably won't make a lasting effect. But if there's a lot of clay down there, it could get ugly.

[waterside]

Thanks Bash.

What are the risks with clay?

[SabreKai]

I would think that if you sink deep enough into it, there may be a severe sucking sound as the tide comes back in. IF the tide comes in and you don't rise with it, I'd say the clay won.

[waterside]

Yeah that would be ugly :-) thank goodness its not a bulb keel.

[Bash]

Originally Posted by waterside

Thanks Bash.

What are the risks with clay?

You won't sink as well in clay. This is especially true with a bulb keel (as opposed to a true fin.) In silt or soft mud, the boat tends to stay on its waterline. In clay, more and more weight is transferred to the keel. This means that the scouring action caused by tidal current is going to be tougher on the bottom. In my previous boat, which had a bulb keel (NEVER AGAIN!) I was at one guest dock with a clay bottom, and it felt as if the boat was bouncing on rock whenever a wake came through the marina.

[waterside]

OK that's great, thanks all for the advice I feel much more confident about it all now.
I'll pack a shovel and a very long snorkel but expect the best.

[boatman61]

well you could always knock up some legs...

[markpierce]

There is another concern not mentioned although I doubt it applies to the OP. My 4-foot-draft vessel has the water intake for engine cooling not very distant from the keel. Mud could be jammed into the intake and sucked into the cooling system if resting on the bottom. In my case, I'd want the boat to lean to starboard if aground.