38 



Bom-Trawlen (Fig. 19) bestaar af et poseformet, mod 

 Bagenden spidst indsnævret Net, hvis Mundings Overkant 

 er fastgjort til en, 4, "7 (15 Pod) lang.- rund Bom af Træ. 

 paa hvis firkantede Ender er indsmøget Jernmejer, 0'".8 

 (2 l j- 2 Fod) høje, paa hvilke Apparatet kjøres langs Hav- 

 bunden. Trawlens Længde fra Midten af Bommen til 

 Spidsen af Nettet er 6 m .5 (21 Fod). Den med Blystykker 

 belastede, noget slakke Underkant af Netmundingen er i 

 sine Ender fæstet til Mejernes Underdel og slæber langs 

 Hunden mellem disse, idet den graver niere eller mindre 

 dybt ned i Bundens Materiale. Gjennem en Hanefod af 

 Tougverk. der er fæstet i Øjebolte paa Forkant af Jern- 

 mejerne. staar Trawlen i Forbindelse med Skrabetouget. 

 Til Mejerne og til Netspidsen fæstedes ofte Hampsvabere. 



. ■ Maskerne i Nettet var oprindelig temmelig aabne, 

 saaat det kun kunde holde større Gjenstande tilbage. me- 

 llens mindre Dyr og det tine Slam ;nk igjennem. Efter 

 Professor Sai's's Ønske blev derfor Spidsen af Nettet turet 

 med finmasket Garn. saaledes. at det kunde holde fint Slam. 

 .Med denne Forbedring var etter vor Erfaring Bom-Trawlen 

 et udmærket Bundskrabningsapparat. Dem fangede baade 

 under hurtigere og langsommere Bevægelse langs Bunden 

 og tog ikke alene Fiske og andre Dyr. der bevæger sig frit 

 i Nærheden at' Bunden, men den skummede ogsaa det øvre 

 dyrholdige Bundmateriale at', ja tog endog Stene og det 

 store, indtil 50 Kilograms (100 Pd.) Vægt ind i Nettet. 



Bom-Trawlen havde i sin oprindelige Skikkelse ogsaa 

 den Feil, at hele Systemet kunde svinge sig rundt i Våndet 

 ander Udfiringen, og Apparatet kunde saaledes undertiden 

 falde paa Ryggen, med Bommen ned. paa Havhunden. 

 Denne Mangel blev rettet af Skibsfører Grieg ved at hænge 

 et Lod i slak Bugt mellem Mejerne. Fig. 20 viser dette 

 Arrangement Naar Trawlen begynder at helde fra den 

 rigtige Stilling, i hvilken den blev sendt ud. afslakkes den 

 Del af Touget. der var tast i den Mej. som var nederst. 

 Loddet tråk i clen anden Part alene og drog den Ende, 

 sum var øverst, ned til samme Højde som den anden. 



Til Skrabetoug brugtes ■< centimeters (2 Toms) Toug 

 de tørste 2000 Favne og fr- r > centimeters (2 1 /.. Toms) i 

 Agterhaanden. Begge Slags vai- at bedste Sort russisk 

 Hamp, og Prøvetrosserne besigtigede og prøvede ved Carl- 

 Johansværns Værft. 



Forberedelser til Bundskrabning. Disse begyndte i 

 Regelen strax efter at man var fajrdig paa Bagbord Side 

 med Lo.dning eller Temperaturrække. 



Før at compensere Virkningen at Skibets og Skrabens 

 Bevægelse paa Stramningen af Skrabetouget, qavnlig tor at 

 undgaa farlige pludselige Ryk, var Skrabetouget vist gjen- 

 neiu en Blok, der hang i en Accu/rmdator. Skrabeaccumu- 

 latoren var megel større end Loddeaccumulatoren. Den 

 havde 30 Stropper, al' samme Sinus sinn de ved Lodningen 

 benyttede. Træskiverne, gjennem hvilke Tougstjerterne gik, 

 havde en Diameter af O ra .605 '1 Fod I 1 '/_■ Tomme) og en 

 Tykkelse at' m .050 (1.9 Tomine). Skrabeblokken var af 



Fig; 19 represents the Beaw-truirl used on the Expe- 

 dition. A cønical netted bag is suspended by one side 

 from a round beam of wood 15 feet in length. to the 

 square ends of which are tixed irpn runners. 2 feet and 

 a half high. that support the apparatus when riding over 

 the bottom. The length. of the trawl. measured from the 

 middle of the beam to the apex of the bag. is 21 teet. 

 '1 he lower side of the niouth of the net. weighted with 

 rolls of sheet-lead. hangs loose. and is fastehed at either 

 end to the bottom part of the runners, hetween which it 

 drags along the sea-floor. scooping up more or less of solid 

 matter. This trawl is attached to the dredge-rope by means 

 of a rope crow-foot. lashed to eyebolts on the fore part of 

 the iron runners. We otten fastened hempen tangles both 

 to tlie runners and to the end of the hau. 



The commercial trawl. as furnished liv the. English 

 maker, had a rather wide-meshed bag; and hence it brought 

 up none but comparatively large bodies. small animals 

 and fine mud heing washed through. At the instance, 

 therefore. of Professor Sårs. the bottom of the bag w as 

 lineil up to a certain height with yarn netting, suffi- 

 ciently close to retain the finest mud. With this slight 

 moditication. we found the beam-trawl a most efficient in- 

 strument, whether quickly or slowly worked; it not only 

 secured fishes and other marine animals that occur near 

 the bottom, hut skimmed off a thin laver of the surface; 

 nay. it would take in stones. some of them weighing as 

 mucli as 100 pounds. 



In its original fonn. the beam-trawl was apt uaore- 

 over to capsize in the water and reach the bottom with 

 the beam down. Captain (4rieg remedied this defective 

 tendency by suspending one of the cast-iron sinkers in a 

 slack bight hetween the runners. This arrangement is 

 shown in Fig. 20. So soon as the trawl begins to incline 

 from the right position given it at the commencement of 

 the operation. the part of the røpe made fast to the run- 

 ner thén deepest iii the water will get slack. and the weight 

 accordingly act only upon the runner at the opposite 

 end of the beam, pulling it down to a level with the 

 lower one. 



■ The Dredge-rope, samples of which had been examined 

 and tested at the Royal Dockyard of Carljohansværn. was 

 of the hest Kussian hemp. The 2noo fathoms next the 

 dredge were 2 inches in circumference, the remainder had 

 a circumference of 2 1 /.. inches. 



Prejaarations for Thedging — As a rule, the gear 

 was got ready immediatelv after taking - on the port side 

 — a sounding or a serial temperature. 



With a view to take off' the suddenness of the strain 

 on the rope caused by the scraping of the dredge ør the 

 motion of the vessel, the tope was røve through a block 

 suspended to an accumulaior. The acoumulator provided 

 lin- the dredge exceeded considerably in size that used 

 with the sounding-machine. The number of straps was .'i 11 , 

 and the wooilen disks through wliicli the lanvards passed 

 had a diameter of 1 foot 11 1 i inches and a thickness of 

 2 inches. The dredirinu-bloek was of iron. similar in con- 



