One topic to think about when you're working with a builder who will design and build a custom dock for you is whether the structure will have railings. While many docks don't have this feature, having railings offers a number of advantages and may be something that you wish to add to your design. If you wish to move forward with railings, your next priority will be to decide what style you want. Your custom dock builder can build several different styles, including the following three popular options.
There's a good chance that you might want your builder to use wood for your custom dock, which means that it makes sense to have wood railings for this structure. Whether you want the dock's surface made out of pressure-treated lumber, cedar, or another type of wood, you can expect that your builder will use the same type of wood for the railings. While there are many different designs that you can consider, a sensible option is a three-rail design. This type of railing will provide an open look that doesn't make the dock feel cramped. You can choose the size of wood that you want for the railings. For example, 2 x 4 boards provide a heavy, sturdy feel, while 2 x 2 pieces may also be appealing.
Another railing design that can look good on a custom dock is a rope railing. This is a railing that consists of a number of wooden or metal posts that have one or more strands of rope strung between them. The rope can either be pulled taut or draped slightly; this is a matter of your visual presence, as is the diameter of the rope that you choose. This railing design can be appropriate on a dock because of the close association with rope and water activities. For example, you tie your boat to the dock with rope, so the use of a rope railing can feel like a good match.
Your custom dock builder may have experience installing pipe railings on other dock projects and may be able to show you pictures of this work. Even if a pipe isn't the first railing type that comes to mind, it can be an appealing option. Some people favor plastic pipes, while metal pipes can also be an option. One of the nice things about using pipe is that it's available in different colors. For example, a white plastic pipe can look good, as can a black metal pipe.
Reach out to a professional to discuss this and other aspects of dock construction.