English to Spanish Other Archaeology

Hola a todos. ¿Serían tan amables de ayudarme con este término? Tomado de un libro de arqueología subacuática:

Swimline (freeline) searchesPractice, patience and perseverance are

prerequisites forthis method but it has been used with success on

manyarchaeological projects in the past. The system relies on a string of

divers, often between two and six, spacedalong a tape-measure or graduated

line at intervalsequivalent to less than the limit of clear visibility, so

thatcomplete coverage is possible (figure 12.2). The search is usually

undertaken with a ground-line to guide a con-troller. To enable positions of

objects to be fixed, it is useful also to graduate the ground-line in

convenientincrements. This technique is in fact a large-scale offsetsurvey

(see chapter 14). These ground-lines can be as long as necessary (up to a

kilometre has been known) and should be reasonably straight. To achieve this,

theyare probably best laid from a moving boat, keeping theground-line under

tension while it is being deployed. It can be difficult to lay long

ground-lines precisely, but with practice it is possible. As long as the line

is straight, the positions of the two ends can be fixed (seechapter 11) so

that there will be a record of where the searchtook place.The main difficulty

with this technique is maintainingthe line of divers at right angles to the

ground-line,which inevitably becomes more difficult in poor visibil-ity.

Another difficulty encountered with this method ismaintaining effective

communication between the diversto allow the line to advance smoothly. This

problemincreases proportionally to the number of divers on theline, and it is

also intensified by poor visibility. Usually,if a diver needs to stop to make

an observation, or is readyto move off again, this is indicated to the others

by a codeof signals along the line. With practice, it is possible

tocommunicate quite complicated messages along the con-necting line using a

set of bells (short tugs) and pulls (longtugs). Standard rope signals can be

found in many div-ing manuals and additional ones appropriate to the

individual operation can be devised.Another difficulty is the variation in

dive durationbetween individuals at the same depth and in the sameenvironment

caused by dissimilar equipment and breath-ing rates. Matching the contents of

the divers’ breathing-gas supply will help. It is considered best practice to

terminate the search when one of the divers needs to surface for whatever

reason, unless a buddy diver canaccompany the diver to the shore or

safety-boat.

Plotting the position of observations during the searchcan be achieved in the

same way as described when usingthe offset survey method. All that is

required is to recordthe distance along the ground-line and a distance out at

right-angles to the ground-line. To achieve a detailedsurvey two divers can

move slowly forward using a short rigid rule or tape, at right-angles to the

graduatedground-line (figure 12.3). Alternatively, markers can bedropped at

points of interest and the position fixed later.If the number of markers

needed by each diver is exces-sive, an alternative search method, such as the

jackstay system (see below) may be more suitable.Swimline searches are often

more effective in clear,shallow water, but this technique can be deployed

suc-cessfully in deeper water if consideration is given to usinga secondary

pair, or team, of divers to record the pointsof interest located by the

search team. With discipline, goodcommunication and rehearsed procedures this

techni-que can be very flexible, allowing the search-line to bestopped

periodically to record the nature of the sea-bed,or count the number of

surface-indicators (potsherds, forexample) to compile a distribution-map.


Muchas gracias de antemano.

Saludos.