I think that I am cheating a little bit on my underwater pull when I get tired by dropping my elbows and losing the anchor for my pull. I think it is largely the result of not being in the water enough and not having the conditioning and endurance in my swim muscles to continue good form after swimming for a while. I talked with the masters swim coach at the club where I work out (note: I am not on the masters team) and he said he has a paddle that will (1) help with my hand entry, (2) keep my underwater pull in shape and (3) develop some strength and endurance in my shoulders and upper back. Is this too good to be true or is this a possibility. And if it is true, what brand of paddles would you suggest? Thanks in advance.
Jeff
Paddles can and do help, but you have to be careful not to let them be a crutch. I have swimmers that I coach that can do distance swims faster with paddles if they wanted to than without.
I think the paddle he is talking about is called the tyr catalyst. They have a cutout on the inside top of the paddle that helps do all those things (plus put a little less stress on your shoulders.)
I follow the rule for myself and my swimmers to not swim more than about 20% of a workout pulling. I too…love pulling with paddles, but it is not the same as just plain swimming.
I was only swimming about 6000-7500 yards a week over the last few months, but have committed to upping that to between 12,000 to 15,000 a week from here on out. I am not trying to become the fastest swimmer, but rather trying to work on technique, strength and efficiency so that I get out of the water in good position without being completely worn out. FWIW, I was planning on doing one set per workout with the paddles just to get a better feel for the proper pull. I currently swim about 1:25/100 yards, but it is a very inefficient swim where I feel like I am having to power through the water.
Jeff
As they say…more is more 
I love doing the following set…insert your intervals where need be. I like to get in the pool, get a high quality short workout in…and get out.
Rd 1
300 pull
3x100 swim (10 secs rest type interval)
6*50 swim (5 secs rest type interval)
Rd 2
300 swim
3x100 pull (10 secs rest type interval)
6*50 swim (5 secs rest type interval)
Rd 3
300 swim
3x100 swim (10 secs rest type interval)
6*50 pull (5 secs rest type interval)
Bam 2700 yards right there. Get a warm up and cool down and I’m done. Plus I like it b/c you get to change up alot. I don’t take a rest btwn the pulls and swims. Just yank paddles and buoy off. The only significant rest I do is after the 300 swim while I get my toys on if need be.