If you keep your feet on them and restrain the paddles from freewheeling, yes, much more. Rather like dipping your oars in, in a rowing boat and ‘checking’ the boat’s progress.

This would be most pronounced on a traditional peddle boat, with rotary paddle wheels. However, there are some, more innovative craft which use flipper-style paddles, and in the case of this type the effect would be negligible – more akin to a scuba diver resting their flippers.

See this type of boat here, at:

http://www.youtube.com/watch?v=mTlgo-wQlvo&feature=related

So, the point is that in order to be a good swimmer, you must be able to hold your wrist, hand and fingers flat and those forearm muscles must be strong.

But, I don’t know where you (or anyone else) got the idea that having large/strong forearms would affect your streamline but, that does not happen … not one bit.

So, lift weights to make your forearms strong. A great lift to do is to take a dowel (cylindrical piece of wood) that is about 3-4 cm in diameter. Drill a hole through it in the middle between the ends. The hole should be large enough to thread a piece of rope that is about 2.5 to 3 feet long.

Tie a 5 to 10 pound (2 to 4 or 4.5 kg) weight on the other end of the rope. Now, with your fingers going over the top of the dowel (you can buy one at any home improvement store or most hardware stores) roll the dowel so the rope rolls up. Then, after letting the weight down, turn your palms upward and roll the weight up again.

This is a KILLER exercise and will develop your forearms. We used to call our arms "Popeye" arms … you’ll see and feel why. (If you don’t know who Popeye is, look up "Popeye the Sailor Man" on google and when you find a cartoon, look at his forearms).

When coaches first discovered the use of paddles in the 1970s, coaches thought the answer to your question was an absolute YES. They had swimmers doing 10 to 15,000 yards per day with paddles. Then, reality set in as the stress placed on swimmers’ shoulders for that AMOUNT of swimming caused repetition injuries and swimmers were out of the pool from the injuries for a month or two recovering from the strain of the paddles.

However, if paddles are used properly, they can help you to develop swimming strength.

First, use the paddle for low speed drills including sculling drills. I also have my swimmers work on stroke skills with paddles. However, the paddles are used as follows: We use flat paddles and use ONLY the single finger strap for the middle finger and DO NOT use the wrist strap. ALL fingers, including thumb and little finger, are kept flat on the paddle. You do NOT hold the outer edge of the paddle by wrapping your thumb and little finger around the side.

The purpose of using the paddle in the fashion I described is that you can tell if your stroke is proper because if the paddle stays flat on the palm of your hand, your stroke is correct. If the paddle pulls away from your hand then you are dropping your elbows and pulling with your elbow which pulls the paddle off your palm.

Paddles, used in the same fashion as I just described, should be used while doing sculling drills.

Then, a few days per week, paddles should be used on short sprints. Using them on short sprints will cause you to gain strength for your stroke.

Here is a website, but it is all in Japanese. So, I am not sure if they can ship to overseas.
If you know someone in Japan, you could ask them to send it to here.