I was curious what ChatGPT would say so I copied and pasted your question (w/o title) and received this in response:

"When choosing a paddle shape for whitewater and recreational power paddling, there are a few factors to consider. While personal preference plays a significant role, here are some considerations to help guide your decision:

Blade Shape: For power paddling, you'll want a blade shape that offers a balance between power and maneuverability. Look for a slightly wider blade with a dihedral or spoon shape. This design allows for more efficient power transfer and reduces flutter, providing stability during powerful strokes.

Surface Area: A larger blade surface area will generate more power with each stroke. However, keep in mind that a larger blade requires more effort to paddle, so it's important to find the right balance based on your strength and endurance.

Shaft Material: Since you mentioned considering a straight shaft, it's worth noting that straight shaft paddles are commonly preferred for whitewater and power paddling. They offer a more direct and intuitive paddle feel, which can enhance control and power transfer. Consider a shaft material that suits your preferences, such as carbon fiber, which tends to be lightweight and stiff for efficient power transmission.

Length: You mentioned already knowing the length you need, which is great. The appropriate paddle length depends on factors like your height, boat width, and paddling style. Generally, for power paddling, a slightly shorter paddle may provide more control and maneuverability. However, it's crucial to try different lengths and experiment to find the one that feels most comfortable and efficient for your specific needs.

Test and Experiment: Ultimately, the best way to determine the right paddle shape for you is through personal experience. Try borrowing or renting different paddle shapes and sizes to see how they feel on the water. Experiment with different blade shapes, surface areas, and shaft materials to find the combination that provides the power and control you desire while remaining comfortable during extended paddling sessions.

Additionally, consulting with experienced paddlers or visiting a specialized paddle shop can provide valuable insights and recommendations based on your specific needs and preferences. They can help you try out various options and provide guidance based on their expertise.

Remember, finding the perfect paddle shape is a personal choice, so take the time to explore and discover what works best for you in terms of power, control, and overall enjoyment on the water."