If we look at the standard references on clothing, waistcoats and vests were made from woven material.
However, Mary Thomas gives a stranded knitting technique (weaving) that she said was much used for Victorian waistcoats. In Weldon's Practical Knitter, we see a large number of patterns for waist coats, vests and under vests, some of which are long sleeved.
Thus, it is clear that the Victorians wore knit vests and waist coats without this practice intruding into fashion history.
One advantage of weaving is that it produces a warmer fabric with less need for knitting tightly. For the same warmth, a waist coat of this kind of knitting requires more wool and is heavier and bulkier than a waist coat knit with long needles and knitting sheath of the same warmth.
When I knit with circs, I did some weaving and as I moved to long needles/knitting sheath, because it was very easy. However, as I came to understand how warm fabrics knit on long needle with a knitting sheath could be, I stopped weaving because it added weight and bulk to an already warm fabric.
It is interesting that directions for weaving do not appear in the Weldon instructions.
And when we look at Colonial trade of Maryland, 1689-1715 (1914) by M. S. Morriss, in Appendix II, (imported from England) we do find both cloth and “ worsted” stockings and both wool and worsted waistcoats, which I take to mean that there were knit waist coats. The book is reprinted in The Johns Hopkins University Studies in Historical and Political Science (1914) by Herbert Baxter Adams
Taken in the context of the above imported garments, the material at http://www.history.org/history/clothing/men/mglossary.cfm tells us that a sailor’s waistcoat could have sleeves, be called a jacket, and be worn outer most. This is certainly consistent with seamanship texts from 1750 to 1840.