sgòrradh m. [ˈs̪kɔːɍəɣ], gen. sgòrraidh [ˈs̪kɔːɍi], ‘a prop to support a boat on land’ is derived by MacLennan (1925),
So also Stewart 2004, 413, and Ó Muirithe 2010.
Christiansen (1938, 3, 9: sgoradh)
So also de Vries 1962.
and Cox (2007b, 60 fn 24) from ON skorða f. ‘idem’; McDonald (2009, 404: sgoradh) considers the derivation likely.
ON skorða yields SG sgòrradh
As in MacLennan 1925 and MacDonald 1946, 21.
regularly, and in some dialects sgòradh (cf. ON garð acc. m. > SG gàrradh, gàradh, s.v.). SG sgòrradh (sgòradh) is also used as a verbal noun, e.g. tha an t-eathar air a sgòrradh ‘the boat has been propped up’; hence, perhaps, the derivative substantive sgòrr (sgòr) ‘prop’
As in Faclan bhon t-Sluagh˄: sgòrr; Mackenzie 1910, 385: sgòr.
and the derivative verb sgòrr (sgòr) ‘to prop up’.
As in Dwelly 1911: sgorr [= sgòrr]; MacDonald 1946, 21: sgòrr; AFB˄: idem.
SG sgòrr ~ sgòrradh also yields sgòrr ~ sgorradh
As in Dwelly 1911: Lochalsh; Wentworth 2003a: Gairloch; AFB˄. Cf. pl. sgorraidhean (Dwelly ibid.), sgoraidheannan (Faclan bhon t-Sluagh˄, s.v. sgoradh: Ross-shire). Also sgoradh, as in Christiansen 1938, 3, 9: Lewis (although the orthography is untrustworthy); McDonald 1972: South Uist; and Faclan bhon t-Sluagh˄: South Uist, Skye, and, s.v. sgor, Ross-shire.
with a short stressed vowel by analogy with, for example, SG geàrr ‘to cut’ (< EG gerr, with the vowel lengthened before final -rr), but gearradh ‘cutting’ (with no lengthening before non-final -rr); cf. SG (sg.) sgòrr ‘peak’ (sgùrr) ~ (pl.) sgorran (sgurran), and perhaps also through conflation with SG sgor ‘to cut, hack, gash etc.’ ~ sgoradh ‘cutting etc.; furrow, wrinkle etc.’.
Note also the occasional spelling sgorradh for sgoradh ‘wrinkle’, e.g. MacCoinnich 1963, 173.
Cf. SG sgorraich ‘to brace oneself’ (Faclan bhon t-Sluagh˄: pronounced sgoraich [sɡɔɾiç], Lewis) and sgorrachadh m. ‘the act of sitting up; an expectant attitude’ (MacLennan 1925): although MacLennan (ibid.; so also Stewart 2004, 413) derives sgorrachadh from ON skorða ‘to prop up’, it is the verbal noun of sgorraich, which is simply a derivative of SG sgòrr + the verbal ending -ich;
cf. SG sgoran *[ˈs̪kɔɾan] ‘a buttress of turfs or divots usually placed one on each corner of a [peat-]stack’ (Faclan bhon t-Sluagh˄: Harris) ?< sgòr(r) + the agentive (nominally diminutive) suffix -an.