Yachts standing up in harbours when tides out?

[weave]

Hi all,

Hope right section but just wondered how yachts stay upright in harbours when the tide goes out?

This is layout related as thinking of having an area for yachts but with the tide out, similar to this....

http://travel55.co.uk/uploads/images/holidays/grand-uk/Wales/wales-tenby.jpg

Thought the wet sand would be easier to model than the sea.

Have Googled but can't find the answer I'm looking for. I love boats and ships to look at but know nothing about them.

Was thinking that the tide goes out and keel sticks in the sand. When the tide comes in it lifts it. Seems a bit hit and miss.

Sorry if being stupid (again).

Also if that is the case, I'd need to make some keels for my yachts.

Thanks for any help

weave

[Malc]

Some boats are called bilge keels, they have two keel boards that act as legs.

[Outtenbach]

Something like this??


"This is a free image from the interenet" I Googled  Yachts at low tide  and got loads............


Tony

[Jon898]

Most people in a drying harbour will have a boat with either twin keels or with substantial bilge keels in addition to the main (centerline) keel.  Fishing and displacement motor boats will often have a hull that is happy to rest on the bottom with only a slight list to one side or the other (as long as the rudders and propellers are well protected).  For boats with a deep keel, the usual solution (absent a harbour wall to rest against) is to rig "legs" to keep everything vertical...Google "yacht legs" and you can see lots of examples.

Jon

[weave]

Thanks guys,

All makes sense. Didn't have the right words to Google.


http://i84.photobucket.com/albums/k5/VEGA165/Vega/VLP.jpg

Cheers weave 

[Bealman]

Interesting! The huge difference between high and low tides has always fascinated me on my UK trips. We have a very picturesque boat harbour here in my home town, but it's always full of water. We just don't have those sort of tides here.

I don't know why... something I've never really thought about until now.

[Luke Piewalker]

What they all said...

Mostly twin keelers that will sit upright in the mud quite happily. You'll also see some yachts with a retractable centreboard that just sit.

[DELETED]

Some boats are called bilge keels, they have two keel boards that act as legs.

..."keel boats" or "fin boats" from my experience.  I would say bilge keels are normally fitted to displacement type hulls, to prevent static rolling for more than anything else but extended ones fitted in small yachts to allow them to sit beached -but they're normally allot less effective than a single keel when sailing.  Twin keels protect the rudder and any prop also.

I have seen unscrupious owners leave (single) keelboats beached -not very advisable unless and the very 'odd finboat laid over (an expensive mistake probably from forgetting to secure the fin up, probably needing a new fin and box inside).

Was thinking that the tide goes out and keel sticks in the sand. When the tide comes in it lifts it. Seems a bit hit and miss.

Ifa boat is beeeched on really soft mud they can stick-in, but the stick on the small area of the keel is usually much less than the buoyancy on the hull so they usually re-float.

Interesting! The huge difference between high and low tides has always fascinated me on my UK trips. We have a very picturesque boat harbour here in my home town, but it's always full of water. We just don't have those sort of tides here.

I don't know why... something I've never really thought about until now.

...All to do with the moon, your place on earth and your topography (and the time of year and weather!).  Tidal difference is circa 6m in a small port near me.  That's a huge difference I had to account for in a new gangway for an offshore vessel a few years back.  More like a mini-link span than a gangway.

When we were sat diving alongside offshore platforms tides could be a real pain in some areas.  Depending what drawings you got, different drawings quoted water depths relative to different things so you had to be on the ball setting divers depths and work sequences and confirming against the tide tables for that day.  Alongside sequencing the dive orders because divers just can't go up and down in depth and have limited working times, and when the tide was at a max, currents usually too strong to do any useful (safe) work.  You might not expect that 200 miles out at sea!

...sorry, not talked Naval Architecture / Offshore for a while (my profession).

[MalcolmInN]

Facinating stuff 

not talked Naval Architecture / Offshore for a while

I am tempted to say " that's a 'rhumb line' to read on a model forum " !

[DELETED]

Facinating stuff 

not talked Naval Architecture / Offshore for a while

I am tempted to say " that's a 'rhumb line' to read on a model forum " !

...when is a straight line not a straight line or something like that?

[Zogbert Splod]

I well remember, when we got a new engineering hand on the survey ships I worked on, the problem we used to set them:
When the tide starts to rise, how many rungs of the over the side ladder will end up under water?

I read a book a couple of years back about Harrison and his clocks and watches, can't remember the title - fascinating book though... When you think that he started out as a joiner and built his early clocks out of wood, it's amazing.  He was so badly treated at the time too.

[jonclox]

I read a book a couple of years back about Harrison and his clocks and watches, can't remember the title - fascinating book though...

Your thinking about  "Longitude" which is available in book or dramatized DVD versions.
Tho a retired horologist I`m afraid I never read the book mainly because we had to learn (facts long forgotten now) all the nitty gritty facts about Harrison and his problems I have seen nearly all of his creations (either the originals or faithful replicas) over the years but never had to work on any of them  :'(

[Zogbert Splod]

I read a book a couple of years back about Harrison and his clocks and watches, can't remember the title - fascinating book though...

Your thinking about  "Longitude" which is available in book or dramatized DVD versions.
Tho a retired horologist I`m afraid I never read the book mainly because we had to learn (facts long forgotten now) all the nitty gritty facts about Harrison and his problems I have seen nearly all of his creations (either the originals or faithful replicas) over the years but never had to work on any of them  :'(

That's the one, yes!
Interesting that you come at the thing from the other side in a way.  I spent many (too many) years as a hydrographic surveyor.  Mr. H's work is only of historical interest these days since the advent of electronic clocks and then GPS.   But my background, like your own, does allow me to appreciate what the man achieved.  He was so badly treated as regards the prizes and payments offered for success too.
Thanks for the memory nudge .....