Hot answers tagged

15

I think Wikipedia article on Fjard has a very good explanation: Although fjards and fjords are similar in that they are a glacially-formed topography, they still differ in some key ways. Fjords are characterized by steep high relief cliffs carved by glacial activity and often have split or branching channels. Fjards are a glacial depression or valley ...


15

Yes. My wife is a geologist and has been on a couple of research cruises in the south Pacific and Indian oceans. It used to be quite common to have a "swim call" when the seas were calm. The vessel would stop, and the crew and scientific staff would go for a swim. In one case a student lost her leg to a shark during a swim call on a NOAA ship. I believe that ...


14

This is highly dependent on the type of water as well as the location, but I'll summarise a few things to be aware of. In many locations most of these dangers won't factor in, but they're useful things to bear in mind if you're trying to assess the danger of a particular body of water. I'll focus on the sea here - for other things such as rivers similar ...


12

You need to distill it - I'm assuming that freezing is not an option (unless you're camping in the extreme latitudes). This is easiest, as the ice on top is almost pure water. Where you don't have a freezer available - boiling the water, capturing the steam and condensing it back to water will provide pure water.


10

On water, you can use the curvature of the earth to help you, and change your height instead of moving. According to the Boat Safe Kids web site, the formula for how far away the visible horizon is over water (in other words, how far you can see) is 1.17 * sqrt(eye height in feet) = (distance in miles) While wikihow says sqrt (1.5 * eye height in ...


9

Outdoors you can dig a hole and build SOLAR STILL. It is quick and dirty but works very well and it is time tested. Or you can put big plastic bag over brach with a lot of leaves on it and put rock on the bottom to capture the water. Make sure you don't do it on foliage that is toxic to people. If you have the bucks you could get a portable Reverse ...


9

No, gulls (of some species at least) steal food from other birds by moving them until they drop it. They must then be adept at snatching the falling food in mid air. There's material of interest in the Wikipedia article on seabirds - search for kleptoparasitism, reference 23 looks particularly interesting. The article on mobbing also hints in this ...


8

I have a couple of extra points that were always relevant for us as kids growing up in an extremely tidal area (peaking at 16knots - 30mph!): Between islands, tidal races are usually predictable, and the local tide chart will let you know when slack tide (either high or low) is - these will be relatively safe times to swim. Halfway between these times the ...


8

For practical purposes, rarity is beyond difficult to answer. Sure there may be a biological survey buried somewhere in some journal, but specific topics like that don't get much traction outside of small specialized communities of biologists. For a heuristic, I have used a combination of google images and pricing. For google images there are certainly ...


7

First things first you aren't going to be able to get longitude without an accurate clock and/or a tome of sight reduction tables. Without those aids which you'd be hard pressed to create while marooned on an island your navigational options are limited. The best you can really hope for is to follow a latitude line/plane. I think a cross staff would be an ...


7

You have two questions there. I will try to answer both: 1) Triangulation - if you can reasonably accurately pace out a 100 metre baseline and can estimate angles to within a few degrees then a rough estimate of distance is possible. An example from eso.org - in reality it is much easier than this as you can use very rough estimations to make the ...


6

Sunscreen and lip balm, saw a show where the people were burned badly. But that is something that you either have or don't. Your pants can usually be tied at the legs to create a short term Floatation Device. The "Deadman's Float" allows you to conserve a lot of energy. Basically you hang like a jellyfish in between breaths. As you breathe, kick and ...


6

The blue-ringed octopuses (genus Hapalochlaena) are three (or perhaps four) octopus species that live in tide pools and coral reefs in the Pacific and Indian Oceans, from Japan to Australia (mainly around southern New South Wales and South Australia, and northern Western Australia). They are recognized as some of the world's most dangerous marine animals.


5

Description of "Fjord" A fjord, also spelled fiord is a long narrow arm of the sea, commonly extending far inland, that results from marine inundation of a glaciated valley. The great depth of these submerged valleys, extending thousands of feet below sea level, is compatible only with a glacial origin. It is assumed that the enormous, thick glaciers that ...


5

First things first. You need a sailboat in order to sail. A raft isn't navigated. It drifts and is blown around. If you have a sailboat you already have the navigation tools you need or at least most of them. Any tools that you can make on an island with a pocket knife will be no better than just looking up and recognizing the stars. The level of accuracy ...


5

What your describing is flocking. It's an extremely complex behaviour where individuals react to their immediate neighbours giving the sense that the whole flock moves as a whole. Birds naturally flock (in the air or on the ground) as a defensive mechanism against predators, etc. Though complex there appears to be some basic rules to the mechanism as a whole:...


5

This is really just a hypothesis, but here in the UK we also get mixed wader flocks. A significant reason for large/mixed flocks to occur is predation. Watch out for what happens when a large flock of waders (almost by definition very exposed on the ground) spots a falcon. They scatter in every direction, not maintaining a straight line for any time at all. ...


5

That looks like fossilised coral (possibly a sponge?), the outside is smooth because it's been worn down by the erosion of the sea. There is quite a lot of fossilised corral on the north Wales coast, it was once a shallow, tranquil, tropical Carboniferous sea The Carboniferous period from wiki: The Carboniferous is a geologic period and system that ...


5

The ocean floor is almost entirely undisturbed by waves - What you are finding comes from the coastal littoral. You can gain some general estimates from direction and strength of storms, but the movement of the sea is chaotic overall. Oceanographers can make general statistical predictions, but there is just too much to track. Read this article on the 28,...


5

PLEASE NOTE: The search function on my computer is malfunctioning, and I lost the reference links to the information presented here. I'll add them as soon as things are fixed! What you're seeing is a huge washing up of tuna crabs that has created "red beach" all up and down the California shoreline, as well as other states. This is not the first time it ...


4

Typically, if you are out in the open ocean and do not have a GPS device you don't have any useful way to measure velocity* This may not be a problem though, as what you are wanting is not your velocity, but an indication that you are heading in a straight line to the destination (if we assume a constant current) To do this, what you need is something to ...


4

I also would like to add: plants or sea 'wire' (hope that this is English). They tend to grow along the river banks and if your feet get strangled into it, it might be difficult to get your feet out of it, especially when the river flows.


4

If you aren't drifting, then one item that would be useful is a log. This is as simple as a chunk of wood and a line. Time how long it takes for the log to reach the end of the line. This gives you a consistent idea of your speed at least relative to the parcel of water you are in. A stone on a string acts as a pendulum. This gives you a pretty ...


4

This isn't perfectly safe to swim in open-sea and should be organized. Some dangers - currents, stiffed legs, sea creatures, almost as on the beach and a wild beach could be really unsafe. The main countermeasures are - Still water and weather forecast, off course. Shark or other problems proof nets in the water, also keep people inside in most cases. ...


4

Almost all North American sandpipers nest far up north (from the northern Great Plains to the shores of the Arctic Ocean). They winter in moderate numbers along the coasts, and very large numbers of migrants come through in waves along the coasts in the spring (March-May, mostly). The numbers in southbound migration (August-October, mostly) are somewhat ...


3

In the UK one of the more dangerous sea creatures is the weever fish. They are often found in shallow, sandy water, particularly around Cornwall and the south west, and have venomous spines on their backs. Being stung is very painful and can result in severe swelling. Stings are generally caused by standing on them unawares while barefoot, so can easily be ...


3

You're right that the various species of shorebirds, including in your area, like most of the same types of foods. The diet is primarily comprised of invertebrates such as crustaceans, worms, mollusks, and insects. Although some species are indeed bigger, they tend to co-exist peacefully. One reason is that they have different types of bodies and bills, ...


3

After having a look on Google I found that yes you can use a pull buoy out in open water, and that they are often used in Triathlons to help the swimmer as they will often be very tired at this point and can allow their legs to rest between the bicycle stint and the running stint. This is as they are designed to improve your pull, leaving your legs to 'drag' ...


3

Adding one more, from my own experience: a "false floor". I stepped into a lake fully dressed with shorts and sandals, because I saw it was just 10 cm deep. Unfortunately, what I observed as being the floor of the lake, was in fact the upper layer of plant growth... and the lake was, at this shore, in fact more than 1 metre deep (but shallow enough to ...


3

My surfing/windsurfing knowledge is limited. But yes they can be dangerous and yes you should seek knowledge on currents before surfing anywhere. There are currents that can force you against rocks, or into sea caves or under water of the dreaded rip tides. Rip tides are nasty and can suck you out to sea. My mate was caught in one of these once and in a ...



Only top voted, non community-wiki answers of a minimum length are eligible