Note to Þhorn Gldr 2^I

[6, 8] nǫkkva tanna lagar ‘ships of the teeth of the sea [STONES (steinar ‘colours’)]’: I.e. painted ships. The kenning ‘teeth of the sea’ is interpreted as an ofljóst here; the interpretations given in ÍF 26 and Hkr 1991 are similar though sceptical. Steinn means not only ‘stone’ but also ‘colour (mineral paint)’. Ships may have been painted, as suggested by references to colour, also using the word steinn, in Þfagr Sveinn 3/5, 6-7^II glæsidýr lauks … fagrdrifin steini ‘the splendid beasts of the mast [SHIPS] … beautifully covered with colour’ and Refr Ferðv 3/1, 3-4^III runnit rauðum steini ‘covered with red paint’, in reference to a ship’s bow; while in Hallm Hallkv 9/5^V steinnǫkkva must be not a ‘stone ship’ but a ‘painted ship’. While in the first two examples steini is a dat. with a p. p. (fagrdrifin, runnit, both ‘covered’), the use of stein- in the cpd steinnǫkkva can be regarded as a parallel to the use of tanna lagar as a gen. with adjectival function (cf. NS §135). The use of the pl. tanna ‘teeth’ in the present case may be explained as necessary to fulfil metrical requirements. 

References

1. Bibliography
2. NS = Nygaard, Marius. 1906. Norrøn syntax. Kristiania (Oslo): Aschehoug. Rpt. 1966.
3. ÍF 26-8 = Heimskringla. Ed. Bjarni Aðalbjarnarson. 1941-51.
4. Hkr 1991 = Bergljót S. Kristjánsdóttir et al., eds. 1991. Heimskringla. 3 vols. Reykjavík: Mál og menning.
5. Internal references
6. Edith Marold (ed.) 2017, ‘Hofgarða-Refr Gestsson, Ferðavísur 3’ in Kari Ellen Gade and Edith Marold (eds), Poetry from Treatises on Poetics. Skaldic Poetry of the Scandinavian Middle Ages 3. Turnhout: Brepols, p. 246.
7. Kari Ellen Gade (ed.) 2009, ‘Þorleikr fagri, Flokkr about Sveinn Úlfsson 3’ in Kari Ellen Gade (ed.), Poetry from the Kings’ Sagas 2: From c. 1035 to c. 1300. Skaldic Poetry of the Scandinavian Middle Ages 2. Turnhout: Brepols, pp. 315-16.
8. Tarrin Wills (ed.) 2022, ‘Bergbúa þáttr 9 (Hallmundr bergbúinn, Hallmundarkviða 9)’ in Margaret Clunies Ross, Kari Ellen Gade and Tarrin Wills (eds), Poetry in Sagas of Icelanders. Skaldic Poetry of the Scandinavian Middle Ages 5. Turnhout: Brepols, p. 49.