"Going down the column holding a position!

gabarito (m)
n. template, cutting tool; templet

Creio que "gabaritando" no seu contexto refere-se ao uso de uma ferramenta cortante na perfuração da coluna.

O gabarito submarino é chamado "template", mas nunca vi usado como verbo. Talvez fosse preciso mais contexto, mas fica a sugestão: running the drill string using a template... (ou algo nessa linha)

2 The separate and more efficient running of the different drill strings.
3 The lack of a seabed template with which to clamp the API drill string at the seabed...
http://www-odp.tamu.edu/publications/124E_IR/VOLUME/CHAPTERS...

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Note added at 46 mins (2009-02-09 14:20:07 GMT)
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In the drilling of subsea oil and gas wells, drilling templates are frequently used to provide guidance for the drill string during drilling and to ...
www.freepatentsonline.com/4797035.html

Drilling is achieved by running a drill string through the riser. ... Preferably the method includes the step of attaching a template to the shut off device ...
www.wipo.int/pctdb/en/wo.jsp?IA=GB2005002885&DISPLAY=DESC

Well Template. This Template has 7'6" Centers and a 4.5I.F. Box for attaching to the drill string. 3 Well Template 7'6" Centers ...
www.royalservices.com/prod_drilltemp.asp

It sounds to me as though a drill bit is descending a column and scoring it as it descends. Creating groves/notches/scores/marks/scratches at regular intervals as it goes down the column. It's creating a "gabarito"- measurement template - as it descends. I would go with "scoring the column at regular/pre-defined intervals as it descends". without the context I'm just guessing really