Sitting on keel at low tide

[chris95040]

Originally Posted by danielamartindm

...but in talking to people who actually do it, I found no such problems reported.... it's more of a theoretical issue than a practical one...

Well we just heard from Paul about his non-theoretical stress fractures around keel bolts after keeping his beneteau on a mooring that dries out.

I think what can be said definitively here is you are at higher risk for damage in a mooring that dries out, though results obviously vary.

[ferrailleur]

Originally Posted by chris95040

Well this isn't strictly true, right? I mean, the keel is absolutely supposed to bear the weight of the boat when you are out of the water with the jackstands mostly just providing balance. I guess that's not true for every boat, so don't take that as gospel.

Anyways I agree this is a bad slip for this boat, and with the keel somewhat immobilized in the mud some unusual forces could turn up at the hull/keel interface when there's wave action, etc, as you say. Especially if it bounces a bit and ends up putting the rudder in the mud.

I wouldn't loose sleep over it on an older design, but I wouldn't go asking for trouble with Beneteau. Not saying they are bad boats, just seems to be a lot less margin for error with the keels than an older or more overbuilt design.

I read somewhere the equation: Beneteau = IKEA-type mass produced plastic boat!
????
You say?

[Paul Kelly]

Originally Posted by chris95040

Well this isn't strictly true, right? I mean, the keel is absolutely supposed to bear the weight of the boat when you are out of the water with the jackstands mostly just providing balance. I guess that's not true for every boat, so don't take that as gospel.

Anyways I agree this is a bad slip for this boat, and with the keel somewhat immobilized in the mud some unusual forces could turn up at the hull/keel interface when there's wave action, etc, as you say. Especially if it bounces a bit and ends up putting the rudder in the mud.

I wouldn't loose sleep over it on an older design, but I wouldn't go asking for trouble with Beneteau. Not saying they are bad boats, just seems to be a lot less margin for error with the keels than an older or more overbuilt design.

Chris, there is a difference between a boat's keel bearing the load when out of the water and the keel grounding when in the water. I don't know whether you have ever watched a tide coming in, but the process of boat flotation is not smooth especially when there is a wind blowing. In the course of flotation - and that may take 30 minutes or more - the keel will quite possibly bump on the bottom as the tide comes in and gradually lifts the boat's hull.

Now I have no scientific proof that this causes damage to the keel, but it seems entirely logical that if the keel is being bumped in that manner twice a day, then over time that could quite possibly cause stress fractures around the keel bolts. Boats without lifting keels weren't built with that in mind.

By the way in my view the older Beneteaus were generally well designed and well built. The most recent ones are enough to make you weep. I'm not a surveyor so treat that as you may.

[chris95040]

Originally Posted by Paul Kelly

Chris, there is a difference between a boat's keel bearing the load when out of the water and the keel grounding when in the water.

Paul, I agree. Did I not make that clear?

[Cloroxbottle]

If anyone has any further questions about this, here's a short answer. Don't do it.

Its a bad enough process settling down onto the bottom in calm conditions. But when that ebb tide coincides with say, a code frontal passage with winds pushing you away from your tie.

You become keenly aware of the fact that your dock lines are serving the same purpose as a set of metal supporta would when hauled out.

[SV Siren]

My answer would be "It depends". What bottom type underneath your boat would dictate what you may wish to do. If it is just mud, and it is just resting then it might not be too bad. It the tide is sufficient so that your rudder comes in contact with the bottom, and then you get movement due to waves/wind and the like you may damage your rudder-not good. My new to me boat sat on the bottom at low tide. Mostly it was silted in mud, but upon haul-out for transport immediately following survey, it was noted that a gouge had been created by something in the mud on the encapsulated keel, necessitating repairs down the road, which I will address. The anti-fouling had also been worn clean off along the entire keel bottom, over the course of several months.


If it were me, I would have a conversation with the marina and request to be moved to a deeper slip.

[billknny]

Our members from much of the UK and Northern France must be having a real hard time keeping a straight face with the people proclaiming on here that no boat should ever sit in the mud EVER!

The real answer is, like so many things sailing, IT DEPENDS.

It depends on the hardness of the bottom. Obviously rock would be a bad idea, hard sand is also potentially a problem because it is... well... hard! Thousands of boats sit is soft mud twice a day every day for decades. Many on moorings in fairly unprotected estuaries.

It also depends on the boat. Obviously a proper bilge keeler is made for just this. But lots of other boats can "take to ground" just fine.

Boats with high aspect keels and especially high aspect spade rudders might not want to be touching bottom hardly ever. Boats built like modern Bendy-toys also might consider not touching anything harder than salt water.

[boatman61]

Billknny..
It is hard keeping a straight face.. but then one only knows what one cares to learn.. in the UK there's a variety of ways used for drying moorings from twin and triple keels to beaching legs on long keelers.. drying out alongside for maintenance between tides with appropriately built fins is also done by many..
Living with big tides brings out the ingenuity to overcome..
However with many of todays plastic fantastics a cradle is the only option.