I have experience with a swing keel (Mariner 19) and fixed full-draft fin keels (Tanzer 7.5 and Tanzer 29), all on the Great Lakes(ish).
I never really took advantage of the Mariner's cast iron swing keel as far as gunkholing. One season with a low water level, I forgot about a submerged rock. The keel banged along pretty loudly but the boat and keel were otherwise indifferent. I could easily trailer the boat on a near-stock powerboat trailer, which was also a super convenient off-season cradle. The leaking-is-normal pivot bolt was a fussy pain.
The Tanzers have conventional fin keels, 5-5.25 feet, exterior cast iron attached with bolts. Most of the good anchorages in the Great Lakes are sufficiently deep. One time I grounded on a sandbar and was able to motor off with the crew and me hanging off the side. Otherwise, knock on wood, I haven't gotten intimate with rocks (yet) on my T29, but we've all heard stories.
I'd guess about 1/3 of the keels I see on the Great Lakes are shoal draft especially for bigger boats, say > 35 feet. I've heard of a few deep fin keels, > 6 feet, get stuck in weeds or mud towards the end of the season. In my case, at haulout the crane is at the shallow end of the marina. The water is barely deep enough but the weeds slow me down to where I'm at half throttle or more to reach a leisurely crawl.
I never really took advantage of the Mariner's cast iron swing keel as far as gunkholing. One season with a low water level, I forgot about a submerged rock. The keel banged along pretty loudly but the boat and keel were otherwise indifferent. I could easily trailer the boat on a near-stock powerboat trailer, which was also a super convenient off-season cradle. The leaking-is-normal pivot bolt was a fussy pain.
The Tanzers have conventional fin keels, 5-5.25 feet, exterior cast iron attached with bolts. Most of the good anchorages in the Great Lakes are sufficiently deep. One time I grounded on a sandbar and was able to motor off with the crew and me hanging off the side. Otherwise, knock on wood, I haven't gotten intimate with rocks (yet) on my T29, but we've all heard stories.
I'd guess about 1/3 of the keels I see on the Great Lakes are shoal draft especially for bigger boats, say > 35 feet. I've heard of a few deep fin keels, > 6 feet, get stuck in weeds or mud towards the end of the season. In my case, at haulout the crane is at the shallow end of the marina. The water is barely deep enough but the weeds slow me down to where I'm at half throttle or more to reach a leisurely crawl.
