Moorings with a fin keel.

Discussion in 'Motorsailers' started by a.g.turner, Sep 23, 2010.

  1. a.g.turner
    Joined: Aug 2010
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    a.g.turner Junior Member

    As you may know from my other posts I'm very new to sailing.
    I've got myself a lovely Pandora International Fin Keel, which is fine and the main mooring i have available is in deep water so no problems.

    But, i'm wondering.
    Can I bring the boat into docks which dry out, knowing that when the tide goes out my boat will be on it's side until the water comes back in?

    Will this damage te hull or is it an ok thing to do, aside from the fact that i'd obviously have to make sure the mast wasn't going to foul other baots, objects or obstruct the passage of other craft.

    Or is this a big NONO?

    Andy
     
  2. apex1

    apex1 Guest

    The latter Andy.

    The boat can stick to the mud and be flooded with the rising tide.


    Regards
    Richard
     
  3. ironbearmarine
    Joined: Sep 2010
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    ironbearmarine Junior Member

    Andy,
    I believe there is another there is another thread about using legs to create a stable tripod. My Colin Archer has such Careening Legs and allows her to stand so that I can clean/inspect/ repair anything below the waterline when the tide is low.
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Letting the boat take to ground once or twice daily will quickly destroy her. She's not going to just flop over a wait the returning tide. She's going to be driven up and down repeatedly for an hour or so at the rush and ebb of each tide. This tends to pound the hull to death in short order.

    Even if you put legs on the boat, so she doesn't flop over, it's not good on the hull to let it take to ground at each tide. I've never lived in as dramatic a tidal area as you are A. G. I do know that bilge keel yachts (an option on your boat) take to ground regularly, as do centerboarders, but centerboarders take the grounding on a large area of bottom and the bilge keel boats hefty twin keels.

    I wouldn't want my boat to take to ground daily. If you want to see what your boat will go through stop down at the local docks and watch the tide go out. You'll see boats pounding hard on the bottom from wave action, passing boat wakes and wind. Maybe in these large tidal areas, the water level drops so fast, it's not as bad as I imagine, but I've been aground enough to not want to intentionally do this daily.
     
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  5. a.g.turner
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    a.g.turner Junior Member

    Caernarfon harbour

    Yes, in Caernarfon harbour the tide goes between right out and about 10 or 12 feet at full tide.

    I do know of one guy who moors his boat hard against the harbour wall and lashes the boat to the side so that it doesn't tip over but when I heard this I thought, even from my novice position, "this can't possibly be a sensible thing to do regularly"

    There are plenty of regular morrings about in deep water so it won't be a problem.

    I may actually use my little mirror as a tender so I can explore the bays and close coast in that.

    Andy
     
  6. apex1

    apex1 Guest

    Many boats in the Channel area are moored tied to the pier, or with legs, but thats is in calm waters inshore.
     
  7. PAR
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    PAR Yacht Designer/Builder

    Again, I've never lived in these great tidal range areas, but I would suspect you can get away with it in calm waters, but not anywhere there is a big fetch with the prevailing winds.
     
  8. Milan
    Joined: Apr 2005
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    Milan Senior Member

    Yes. It can be done but hull has to be built for it. Point stress from contact with a hard ground is very different then stress from water which is dispersed over wide area.

    We have a lot of shallow waters here and many of our traditional boats are designed to withstand daily drying- out. They are massively constructed with thick planking and thick, closely spaced beams. (One of the reasons for leeboards and popularity of steel in Dutch waters).
     

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  9. PAR
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    PAR Yacht Designer/Builder

    I suspected as much Milan. It goes to say that the taking to ground process is as damaging as I thought. So, to A. G., no don't let your boat take to ground at each tide as a regular cycle. You'll probably bash the fin into the hull in no time. On the other hand, if you need to do some bottom repairs, there's no reason you couldn't let the tide run out while she's propped up, every so often.
     
  10. a.g.turner
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    a.g.turner Junior Member

    Thinking about it, although the tidal difference is massive in Caernarfon Harbour, the water is very calm and sheltered on one side by a massive castle and on the other side by a hill with trees. As a result, there are rarely or never large waves in the harbour its self.
    Also there's pretty deep mud so, as pointed out earlier, one problem would be getting the keel stuck into the mud.

    I'm not thinking for a minute of keeping my boat there or regularly allowing this to happen, i'm only thinking, if I do find myself in a situation where the tide's going out and there's nothing to lean the boat against, so it's going to lie on it's side until the tide comes back in, will this possibly damage the boat seriously if it happens one a single occasion?
    I had visions of the side-wall of the hull it's self crumpling under the weight of the boat, but it seems, it's more likely other things which would damage the boat in this scenario.......

    Andy
     
  11. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Now I see what your question was really about. No, the hull side will not collapse from the weight of the boat on it's side. This said, the boat will bash itself badly if permitted to do this. It's this repeated action that will cause the damage, not the weight of the hull. You see the tide just doesn't suddenly disappear, it takes a while and the boat will hover over the bottom for some time as each wave lifts it and drops it onto the bottom. Even genitally, this will break frames, pop butt blocks and crack planks. Picture using a small hammer on the hull in the same spot. One or two or a dozen hits in the same place may not hurt things, put hundreds, maybe thousands of hits will and this is what happens when the tide goes out. Most boats in this environment will have legs that they can lash to the boat, so she can take to the bottom as the tide goes out.
     
  12. a.g.turner
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    a.g.turner Junior Member

    Thanks PAR

    Thanks PAR, I need to look into this legs thing, sounds interesting.
    I had thought there must be something like that about.

    By the way, just been sailing for the first time in my new/second hand Mirror.
    Took the kids up to Wales and we hada couple of hours on the lake.

    Fantasitc.
    The adventure into the world of sailing begins.....

    Here's some pics of todays adventure........ probably not of much interest to anyone but I'm really excited about it all, totally got the bug.

    I've got the Mirror on the water so I can learn to sail on the lakes over the winter, and my pandora is ready for the spring and some sea adventures.

    Thanks again for everyone's advice and encouragement, such a lot to learn............
     

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  13. a.g.turner
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    a.g.turner Junior Member

    666?

    Just noticed, the number on my boat is 666..... The number of the beast, is that bad???? lol

    Or maybe its actually 999 so people know what to ring when the sail is that way up............

    Andy
     
  14. ancient kayaker
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    ancient kayaker aka Terry Haines

    When I found an image of the boat at http://sailboatdata.com/viewrecord.asp?class_id=3519 and thought about that lovely, delicate fin trying to hold up the boat it made my blood run cold. There are several threads in this forum and elsewhere about sailboats losing their keels - usually after some event that did not immediately detach the keel but compromised the structure leading to failure under sail at sea. The consequences can be severe up to and including loss of life.
     

  15. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Part of the problem with this particular boat is the raked fin, which will put cantilever loads on the keel's root at the fair body. I suspect it would try to stretch the laminate in the forward portions and compress it at the aft end of the root. You can rest assured the structure isn't designed for these loads, so imposing them on the boat twice daily would be a problem.
     
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