Quiz

Plimsoll lines.

Marked off with things like 'winter north Atlantic' to account for temperature and seasonality. Others are summer, tropical, fresh and tropical fresh (I think).

Neil

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Mmm ... ?

Given that the original Plimsoll Line was One Inch ... I wonder what difference the reduction to 25mm made to the load-capacity of the World's shipping.

MichaelG.

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P.S. ... don't remind me about centre-lines ... those interested in profit will always work tolerances to their favour.

Centriufugal force - a force referred to by second rate mathematicians and third rate physicists. There is no such thing. One can only have a lack of centripetal force.

Diane

Edited By Diane Carney on 09/02/2015 21:26:16

Depends on your point of view!

Mark

ps. Or terms of reference

Indeed.
And whether you have ever been a rider on the Wall of Death! Try telling them there's no such thing a centrifugal force!

Edited By Diane Carney on 09/02/2015 23:56:09

Always thought it was Centripetal reaction.

The North Atlantic summer/winter Plimsoll Line would be to take into account the ice melt in summer when the sea becomes less saline.

Ian S C

If it's related to the tidal forces then it would depend where the moon is when the ships set off. If both ships set off when the moon is fully around the other side of the earth then there would be no difference in tides affecting either vessel. The text kind of contradicts itself by stating "all things equal" but there is then an assumption of tidal difference.

It could be argued that if the moon is east of the Azores it is pulling on the earth's crust and causes a tide to travel eastward. As the moon passes over head of the two vessels from east to west, the pull of the moon then starts to pull westward and influences the motion of the westward bound vessel because of a tide now travelling in a westward direction.

Ed.

No tidal differences ED, its all just down to the earth's rotation.

Also, the tides bulge both on the side opposite the moon and the far side*, that's why we have them twice a day!**

Neil

*I should know, having grown up in Barry with a tidal range of 49 feet.

**Unless you live on the Solent.

Still twice a day on the Solent, it is more a longer duration of high tide and a shorter ebb tide period or as least that is how I see it.

Bob

Apparently it depends exactly where you are with double high tides at Calshot.

www.solentpedia.info/our_coastal_zone/waves_and_tides/

Neil

other side of the water

To be honest, with only ten foot of tide I'm surprised you can tell the difference!

Neil

Yep, not like us lads with a "proper" tide like we have up here on the Mersey and Dee

Mark

All of 2/3 of what we have in Barry

When I were a lad I used to sit on the dock of the bay and watch the tide roll away.

Neil

When I were a lad, I used to stay well away from the edge 'cos it used to feel like it was pulling me in! And in those days it was reckoned you would die of poisoning before you drowned - not a problem for you lads that grew up eating bread made from sea weed....

Mark

The one that has not had its bottom scraped. Barnacles giving a major amount of friction. The cross-sectional area and hull length will also influence the speed. And of course the current flow, such as the Gulf Stream. Too many variables in my opinion.

I think the one travelling east would have a problem with the coast, it's only 907ml to Lisbon. It's about 2300ml to America.

Ian S C

> Too many variables in my opinion.

Hence 'all things being equal' - I don't expect anyone to go out with a spring balance and check the results!

Neil

This is starting to sound like the parting off theories. And don't forget quantum effects.