I would greatly appreciate it if any very knowledgable skiers out there that can help me understand the mechanics of how the fin (and adjustments to it) affect ski performance. I'm looking for a deeper understanding than, "If you increase the length, it will lower the tip on the offside." That's good to know, but why is that true?  I have a desire to become a bit of an expert on fin adjustments and I don't know where to start, so here are some questions: DFT: From the D3 website, http://store.d3skis.com/Articles.asp?ID=142: "An adjustment forward (toward the tip of the ski) lifts the front and drops the tail during an on-side turn. An adjustment backward drives the front into the water and raises the tail." Since it is implied that all other variables are constant, I can rationalize the above statement if moving the fin forward makes the ski "shorter" (In the sense that the distance from the tip of the ski to the back of the fin is less as the fin is moved forward). Since binding placement is assumed to be constant this would shift the skiers weight distribution to a point further towards the "back" of the ski. Hence, "lifts the front and drops the tail."  However, the statement only mentions the on-side turn, why wouldn't this be true at all points in the course? Is it really true that a DFT adjustment will not in any way affect off-side turns, or perhaps the degree of angle you can achieve across course, or speed through the course, ect? One of the Adjustment Options on the D3 page I linked to above says, "Difficult to initiate angle across wakes Move fin forward." So DFT has to affect how the ski acts across course as well right... My intuition tells me that a DFT adjustment either makes the ski longer (by decreasing DFT) or shorter (by increasing DFT).  A shorter ski seems like it'd be more responsive but less stable at all points in the course than a longer ski. Is this correct? And, If this is correct, does anyone know why it's true? It kinda makes sense to me that the further forward the fin, the shorter the ski would feel, but why? To explain my confusion, consider if the fin was directly beneath the bindings. The tail of the ski is still back there, and presumably still affecting the skis performance, so although I don't have trouble believeing this to be true, how is it that fin placement fore or aft affects how long the ski feels? Depth: From the D3 website, http://store.d3skis.com/Articles.asp?ID=142: "More depth improves stability and holding power, while less depth makes it easier to turn." I assume the depth of a fin would stablize a ski in the same way that a deep fin would stablize a sail boat, and so this movement makes sense to me. However, I know there has to be more to this fin adjustment since one of the Adjustment Options on the D3 page I linked to above says, "Too much ski tip in water on both left and right turns Increase fin depth." What is the relationship between fin depth and ski tip? Finally, given that you don't feel very unstable, wouldn't it make sense to run as little depth as possible while ensuring the tail of the ski doesn't blow out at the end of most turns? Length: From the D3 website, http://store.d3skis.com/Articles.asp?ID=142: "An increased fin length drives the tip of the ski into the water during the off-side turn. A fin with shorter length raises the tip of the ski. [...] The less the leading edge of the fin is out of the ski, the more the fin will keep the front of the ski up. The longer the leading edge, the more it drives the front into the water." My intuition is that the longer the leading edge, the more water is "hitting" that leading edge and putting upward pressure on the tail of the ski, thereby driving the tip of the ski into the water. Vice Versa for a shorter length. However, this leads to some questions: 1) Why does the description only say this is true on the off-side turn? 2) Wouldn't the Depth adjustment affect the ski in a similar way? I guess is the fin is deep but the length provides for a shallow angle of protrusion from the bottom of the ski, then the pressure caused by water passing over the fin may be less...but I'm just guessing here. 3) Is my intuition actually correct? Wing: From the D3 website, http://store.d3skis.com/Articles.asp?ID=142: "The wing is designed to help slow the ski down as you approach the turns. The more angle you set on the wing, the faster your ski will decelerate into the turns. The tolerances for the wing angle should be kept between 6-10 degrees." I just think that there has got to be more to how the wing affects the ski than this. For example, it seems that a greater degree of wing would drive the tip out of the water while less wing would drive the tip down. So, is there a better way to understanding how the fin works? Perhaps understanding what the fin does on the onside/offside?  Would understanding the fin in a more holistic manner be more useful than the "DFT does this. Depth does this. Length does this." manner? Also, how can I learn what adjustments need to be made to a fin by watching another skier fromt the boat? Thank you to anyone that takes the time to respond to my post.