If memory serves me correctly, Columbia made two different 30 footers and a 29 footer that is sometimes listed as a 30 footer during its history. The first was a 1960''s era Charlie Morgan (I believe) designed keel/centerboarder, the second was built in the early to mid-1970''s and I have seen that design attributed to a number of designers including Wm Tripp, Wm Crealock, and Lyle Hess. The 29 footer was an Alan Paine design and is referred to as a 8.7. I am little mystified at which specific model you considering as none of these came in a long keel model.
The original early 1960''s era Columbia 30 was a nice boat for its day. Build quality was nothing to write home about but they were simple boats that sailed well. Columbias were never all that well built but if the boat was well maintained and upgraded structurally and with modern reefing and winches, I would make comparatively short offshore passages picking my weather window carefully. I would not call these a long keel boat by any traditional definition and I don''t believe that there was either a shoal keel or deep keel version of this boat.
The second boat was a pretty junky design that was built at a low point in Columbia''s history. These were fin keel/ spade rudder boats which came in a deep keel and shoal draft version. A long keel version of this boat was not available.
There is a lot of issues with these boats. They had a poorly designed and fabricated hull to deck joint that was by its very nature was quite vulnerable to damage in docking situations. They were light weight and poorly engineered for thier era with some pretty sloppy glas work and a lot of non-directional fabrics. The rudder was an especially vulnerable design with a somwhat undersized rudder post. Some model years used a cast aluminum stem fitting and aluminum chain plates, which would be at or past the end of their useful lifespan. The chainplates were bolted to the bulkheads which was a common practice in that era but one which could allow rot to occur at this critical connection. Many of the early boats had formica on the bulkhead which masked the rot until the bolt holes failed. (I helped a fellow repairing one of those). I would steer clear of one with either formica or paint covered bulkheads. If I remember correctly, I believe that the deep keel version of the Columbia 30 had a bolt on cast iron keel with galvanized steel keel bolts. The keel bolts would be well beyond their normal useful lifespan of 20 to 25 years. These boat came equipped with Homestrand pressure alcohol stoves and Palmer gasoline engines both of which are getting harder to maintain as parts are getting scarce. Details like the somewhat flimsey stock forward hatch should be upgraded if it hasn''t been already.
These were not very good sailing boats. They had a tendancy to wipe out pretty easily when heeled. I raced aboard one and they were moderately fast for thier day but real rollers downwind. These were the kind of boats that gave early fin keeled boats thier bad handling reputation. These were also very corky boats with a pretty unsettling motion. I know that someone will point out that almost any boat can be fixed up to be an offshore cruiser but from my perspective this would be a very poor candidate.
The 8.7''s were produced at a time when Columbia was in one of its last gasps. Columbia totally retooled its line with models Columbia refered to as its "Wide bodies" (I wonder who thought that was a good marketing idea.) They were later refered to as the "wine glass" series. Columbia really tried to upgrade build quality on these boats and to aim them at the cruising market.
These are hard boats to classify. They were really pretty idiosyncratic. For example they had a fin keel and a skeg but the rudder was not hung from the skeg gaining both the disadvantages of a post hung rudder and a skeg hung rudder but none of the advantages of either. They were compartively light in weight with a reasonably long waterline but the extreme waterline beam, full bow, and pinched stern (a product of trying to fit a wine glass transom on a boat with otherwise modern lines) restricted its performance undersail and power, and gave it a strange motion. They were designed just before yacht design was about to take a giant leap forward and they were left in a strange gulf between the virtues of a traditional design and the design philospohy that was about to emerge. They were constructed during the period when blister problems were at their worst.
I am not sure what to say about going offshore in one. I had a friend who did a lot of cruising in his and really loved the boat. He was pretty open about how the boat sailed, and felt these were not boats to get caught in a blow on, yet he sailed his offshore from Cape Fear down to Florida single-handed which was a long hard thrash to windward in a boat, he described as having poor windward performance and a miserable ride into a chop.