Hi All,
Transom mount anti-spin fins are very common on today's monos and vees. When I got into this hobby in the early 70's, most monos ran fully submerged drives and I did not remember seeing any spin fins on the transom. I guess as speed increases, a boat needs more help to keep it on the water. The look of a huge fin hanging on the transom has always bothered me. Furthermore, I am sure a fin like this will add to the drag. I only install them if have to. In fact I can get away without any spin fins most of the time but I have to be careful while driving or I will spin out.
Since full size boats do not have these fins, I started reading up on some articles on full size crafts. Bow steering in full size crafts is caused by the CG being too far forward and/or the boat trimmed to run too flat (correct me if I am wrong for those of you who run a full sized boat). In extreme cases, bow steering will end up with a spin out. This all make sense to me. But the problem is that my experience with RC monos and vees is the complete opposite. If I trimmed a boat to run loose; either by moving the CG aft or by moving the trim plates up, I am more likely to have a spin out while turning even with a spin fin.
While I am rebuilding a couple of old vees, I started experimenting with set ups and removed the spin fins. I have found that the standard rule of thumb for CG at 33% works quite well. In fact, a well trimmed out boat does not need any spin fins to turn properly at high speeds.
My question is: Do we really need a spin fin? Please share your experience.
Thanks,
kez
Transom mount anti-spin fins are very common on today's monos and vees. When I got into this hobby in the early 70's, most monos ran fully submerged drives and I did not remember seeing any spin fins on the transom. I guess as speed increases, a boat needs more help to keep it on the water. The look of a huge fin hanging on the transom has always bothered me. Furthermore, I am sure a fin like this will add to the drag. I only install them if have to. In fact I can get away without any spin fins most of the time but I have to be careful while driving or I will spin out.
Since full size boats do not have these fins, I started reading up on some articles on full size crafts. Bow steering in full size crafts is caused by the CG being too far forward and/or the boat trimmed to run too flat (correct me if I am wrong for those of you who run a full sized boat). In extreme cases, bow steering will end up with a spin out. This all make sense to me. But the problem is that my experience with RC monos and vees is the complete opposite. If I trimmed a boat to run loose; either by moving the CG aft or by moving the trim plates up, I am more likely to have a spin out while turning even with a spin fin.
While I am rebuilding a couple of old vees, I started experimenting with set ups and removed the spin fins. I have found that the standard rule of thumb for CG at 33% works quite well. In fact, a well trimmed out boat does not need any spin fins to turn properly at high speeds.
My question is: Do we really need a spin fin? Please share your experience.
Thanks,
kez