Not as much of a difference in a smaller boat (less than 12 ft) but it will help in some cases as mentioned above and can be used to reduce swing in winds/currents when anchored or tied off in tandem with an anchor trolley. One recommendation, the rudder they install is the smart rudder system it has two different blade sizes give them both a try. Another thing on the rudder it has adjustable spring tension for deployment so if it is sticking or slamming down too hard you will need to adjust it.
The things I like most about the smart rudders, they use spring tension rather than cords to deploy so they are more likely to bounce back in to position when they hit things. The blade design is near indestructible I have abused both of the ones I have in fresh and salt water and the housing/mount is more likely to bend than the blade. The blade design has less drag than the other rudders which not only gives you better glide but turns better in my opinion.
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