I'm back, and spied a minicup.

[Fintan Murphy]

Well, I'm back from my hols in Spain and France. Probably the best holidays we've had. 3 weeks is the only way to go!

Anyway, there we were, on a little beach north of Barcelona, motoring around in a glass-bottomed boat, and what should I see on the water? Could it be?, are they actually Blue polytarp sails out there?

As we drew closer I could make out the lines, Yes, a STEVENSONS MINI-CUP!

Two guys enjoying themself out in the Pacific, in a Stevensons boat.

Made me all mushy inside (and a bit jealous :? )

There and then, I informed SWMBO in no uncertain terms that the Weekender WILL be finished in July (that is, if she doesn't mind terribly :shock: )

[Dave R1]

Fintan, it sounds like you had a great time. It's always good to see another homebuilt boat to give you the push to get your own done (or togive you the push to tell your bride you'll be finishing it )

By the way, I gather from your post that Barcelona has moved to the western hemisphere. Is that amazing or what? Don't you think that sort of thing would at least rate a small spot in the newspaper?

[Fintan Murphy]

I was wondering why time flew by on the holiday

Ok, so it's the Mediterranean :oops:

What's an ocean between friends.

By the way, it's odd to see a tide rise of about one and a half feet, when you are used to about ten (in the Atlantic). It's hard to know if the tide is going out or coming in.

[TexasPhil]

When I lived in England, we visited the coast a time or two and I was always amazed to see sailboats on their sides, and others laying on the ground. I thought that kinda odd.

Since then, I leared that the tide would be about 10-12 feet there. But the Gulf Coast tide was only about 3. Even when I visited the Atlantic coast, it was only about 3-4 (Florida and North Carolina)

I wonder if the 10-12 foot tide is something to do with being so far north, in which case (Maine would have a big tide too), or if it has something to do with being on the Eastern side of the Atlantic (in which case Spain an Portugal (on the Atlantic) would have a big tide)

Anyone out there that knows?

[Fintan Murphy]

I reasoned that the variation in tide was due to the volume of water.

As tide is a product of the moons gravity, the amount of water pulled through the Atlantic would be rater large. Hence the large tides on Irish coasts. I also noticed, when we were coming back, that the tides on the east coast of France (the same side as Portugal and Eastern Spain) where as big as our own.

The Med, on the other hand, has a smaller volume of water , so the amount being pulled would not be that great. Hence the smaller tides on the west coast of Spain.

However, as has happened before (and will no doubt happen again), I could be talking out of my ass, and there is some other reason for this phenomonon. :roll:

You could be on to something with the latitude however, as my argument does not count for the Irish Sea (between England and Ireland), which would hint towards small tides on the East coast of Ireland, and West coast of England, which is not the case.

A measure of the various tide heights down alond the coast of America would point some way to an answer. If they diminished as you head towards the equator, you would be right about the latitude affecting them.

No doubt the someone will chime in.

[tdrown]

I am going to Brittany in August and hope to do some sailing. The family I am staying with enjoys sailboats and were excited to hear I am building one.

I did a little searching on the internet. Apparently http://www.cruising.org.uk/tideht.htm air pressure can effect tide height. As you may have heard before, the heights tide is in The Bay of Fundy in Canada where tide typically ranges from about 10 meters to 14 meters.

This site looks like it should explain tide height... I have to go put some anti-skid on the deck.

http://co-ops.nos.noaa.gov/restles5.html

[Barry Pyeatt]

It has very little to do with the ocean it is on because Lake Superior on the Canadian/American border has a tide as well.

It has to do (as Fintan statted) entirely to do with the cycles of the moon and its gravitational pull. It has little effect in the tropics and maximum effect in the northern latitudes. Yes, it is a little interesting to see 10-14 ft. tidal changes in the north and none to speak of in the tropics.

[SeaEagle]

There are a number of locations in New Zealand where the tidal current / flow is 12 -14knots (from memory).

I remember trying to motor through a gap between two islands in a 12ft dingy with a 2hp seagull outboard motor (going flat out) and yet bearly moving forward in relation to the shore.

In parts of NZ it is not uncommon to get significant tidal flows, (Buck can probably provide some comment here - I understand he lives in the south of the South Island)

Regards,

SE

[Frank Hagan]

When I was in Ireland I noticed quite a few sailboats with twin bilge keels, allowing them to sit level if they are on the mud after the tide goes out. The only other place I have seen them with any regularity is up in Ray's neck of the woods (and even then, not quite as many as I saw in Bray and Dun Laoghaire!)

The bilge keels extend out a couple of feet at each bilge ... so they look like a sailboat stand sitting under the boat. Not sure what it does to sailing ability ...

[buck]

Luckily I don't live near that sort of tidal race, thought I can well believe it, theres some extremme places around our coasts especially Cook Strait a rather funnelled gap between are two main Islands (which funnels winds from the roaring forties and takes the only tidal gap (between 2 major oceans)in a 1000miles.

Our tidal gap here is 6-7 feet, nothing to radicle. One place I sail is the Otago harbour, 21 km long and only 1-2km wide. Tide pours in and out about 2-3knots, not much good fighting it in a little 16' sailboat with an electric motor unless the wind is strong. I've learn't to use the tides and just anchor and wait if the tides not going your way. There is however a large mudflats area which dry out at low tide and ads character to the place. I'm always a bit of a fan of these wetlands and saltings, they are valuble places to fishermen as they are great fish breeding grounds and often beautiful quiet places sort after by shallow draught yachtsmen.

[Fintan Murphy]

Yeah Frank,

I was suprized to find out that bilge keel boats are not common (or in some cases unheard of) in America. Just another incidence of me assuming that everybody has the same stuff. ( remember the Flymo lawnmower ).

They are quite common in Ireland, and more so in England, and I saw quite a few in France, as well as a lot of centreboarders. The idea is that they are easy to trailer, and drying moorings are much cheaper than deep water ones. It also allows you to walk out to your boat in your wellingtons, get everything setup, and wait for the tide to come in. It also allows you to sail to a lot of places that a deeper draft boat couldn't reach.

As far as sailing ability, one school of thought is that they are not as good as a fin keel, but the other school is that the advantages above outweigh that fact, as well as the arguement that, when the boat is heeled over, the leeward keel is vertical and therefore effecient. No doubt there is a wealth of info on the net under "bilge keels".

[P Doug (WA)]

There and then, I informed SWMBO in no uncertain terms that the Weekender WILL be finished in July (that is, if she doesn't mind terribly )

There is one thing that remains constant throughout the world :wink:

[TexasPhil]

OK, we got latitude, air pressure, water quantity, and geometry...

I could see all of these playing a part of the tide, but which is the primary? We are not talking about what causes tides... that is the moon, and when the moon and sun line up we get super tides.... no, I am talking about why the UK gets 10-15 foot tides, and Mississippi and Texas get 3 foot tides.

The following is my interpretation of NOAA, (Thanks tdrown for the link... http://co-ops.nos.noaa.gov/restles5.html)

The tide is caused by the water chasing the gravitaional pull of the moon, as it sloshes towards it trying to catch up (the earth spins 360 degrees per day, the moon orbits the earth 372.2 degrees per day)

So, as the water is sloshing around trying to keep up with it, there are several factors that affect the tide, primarily where the water is, and where it is going.... so you have a large, deep body of water (ocean) and the tide is chasing the moon (eastward) As the larger water gets pulled up into shallow water, you get a LARGE tide.

Likewise the Gulf of Mexico (large, shallow body of water) has a lower tide surge. Also, the bermuda triangle area is pretty shallow, which would explain the lower tides in NC to FL.

However the opposite is true too... water is sucked from land back out to sea, hence Maine has a large surge becuase the water is sucked out toward the large ocean. (I wonder if the force of the water being extracted is greater than the water returning... in otherwords.... is there more turbulance when the water leaves than when it rises? Ray mentioned Old Sow's Ear... does that occur when the tide is going out?)

Interesting stuff... I will have to spend a little time looking at the rest of the documents from NOAA. I seem to recal something I learned a long time ago, that the gravitational pull of the moon is greater the further north/south you go... so I wonder if that is in the NOAA docs too?

[TexasPhil]

Wow!

NOAA has some neat graphs... take a look at some of the tides online...

http://tidesonline.nos.noaa.gov/monitor.html

Click a region and then on various ports... very interesting.

It is a shame that the rest of the world is not listed here.

Take a look at Honolulu, and Ketchikan Alaska. Alaska is kinda funny... they have two different lows, and two differnt highs. Then, take a look at Unalaska, Alaska.... weird

The Great Lakes are larger than some parts of the Gulf.... hehe

San Diego has 6 foot, double tide

Tacoma and Seattle have a 10 foot double high.

Eastport Maine has a 18 foot tide

Charleston is 6

Most of Florida is 4-5

Key west has a 2 foot tide

Most of the Gulf and the caribian has a 2 foot tide... even LA with a storm surge is still about 2 foot!

[Barry Pyeatt]

Cause and effect relationship. The cause of the tides is the gravitational pull of the moon, it is greater in northern latitudes and southern latitudes because of the tilt of the earth. Two different tides due to the rotational pull of the earth as it rotates and the moon rotates around the earth.

Tidal surges are the effect. Lots of water has to go thru narrow passages.

We have several heavy surge areas with incredible ebb and flow surges, Deception Pass is the most visible and well known here in the Puget Sound area. But all of the water in Puget Sound is effected by the tides and some of the chanels have extremely rapid flow at peak flow or ebb. North in Canada are several narrow passages withextremely heavy flows between the mainland and Vancouver Island. Some of the inlets in Canada have a wall of water moving on some tides.

[Frank Hagan]

Yeah Frank' date='

I was suprized to find out that bilge keel boats are not common (or in some cases unheard of) in America. Just another incidence of me assuming that everybody has the same stuff. ( remember the Flymo lawnmower ).[/quote']

Good old Flymo. My daughter and son-in-law decided to buy another one at the Tesco for under 100 E after trying to cut the lawn with a string trimmer. Seems spring has sprung in Ireland!

For the others: Here's a picture of a steel boat with a bilge keel. Imagine another bilge keel protruding out of the other bilge, and you have a nice "stand" for the boat when the tide goes out and she's "on the mud".

I couldn't find a picture of a smaller sailboat with these keels, but I sure saw a lot of them in Ireland!

[attachment over 4 years old deleted by admin]

[MikeStevenson]

Is a Flymo one of those hovercraft lawnmowers? I always thought that was a fun idea. Now that I have my own lawn, as opposed to mowing the parent's lawn, I'm more conscious of cutting it right. I ended up opting for a reel mower to make clean cuts. Plus it's a little excersie...

Mike

[TexasPhil]

Bilge Keels.....

All the more reason to have a catamaran or trimaran

[Fintan Murphy]

Yea,

flymo is a brand (the original) of the hover lawn mowers.

What I've always wondered is how they hover by blowing down air, and still manage to cut the grass at the same time?

Some type of wizardry me thinks!