Does Speed affect crankbaits?

Been doing a lot of reading to support the claim after about 1mph speed makes no difference to the depth a crankbait will dive. Has anyone ever tested this theory say from 1mph to 3mph will a crankbait really dive no deeper because of friction on the line and etc.
Thanks in advance!

[Ozark Bob]

Trolling diving baits there is little difference in depths vs. speed. In fact many baits will loose depth at some point as they are designed to function best at a small speed range(less than .5mph range). If you are talking about precision trolling, The diver is viewing the lures depth so can tell what difference there is at different speeds. The kicker there is the exact lure(and size) and line diameter is much more important a factor in the depth. The weighted lures are very sensitive to speed. The lower the speed the deeper they get. Bob

[Wall-i-Lama]

There is not a yes or no answer. It can depends on the line, lure type and if weights are being used.

Here is a FAQ and answer from the precision trolling website which provide the best answer I've seen.

Good luck!

FROM PRECISION TROLLING:

"How does speed influence on diving depth?

Trolling speed is an important variable associated with trolling to help trigger bites. To this point we can all agree. However, trolling speed as it pertains to the diving depth of lures and other trolling hardware is a slippery slope that few anglers completely understand.

The facts are that trolling speed influences the diving depth of some devices more than others. Lures and devices that are negatively buoyant or “sinking devices” are very much speed dependent in terms of how deep they will dive while trolled. Speeding up tends to make these lures and devices run shallow and slowing down allows the same devices to fish deeper. Carefully controlling and monitoring trolling speed is in this case a profoundly important part of getting the most from these lures and trolling hardware.
Precision Trolling Data incorporates “trolling speed” into their data on all negatively buoyant trolling products including sinking lures, weighted fishing lines, sinking diving planers, trolling weights, etc. Trolling speed and in many cases several different test speeds are selectable in the app or published on the PTD “Sticker”.

Buoyant devices like floating style divers, floating/diving crankbaits, etc., are far less sensitive to trolling speed in terms of their natural diving ability. The reason is that as trolling speeds are increased, water pushing against the diving lip or dive plane of the device is working to force the lure or device downwards in the water. Unfortunately, at the same time speeding up increases the amount of friction impacting the fishing line which is counter to the lure’s diving ability.

To be clear, the increased friction on the line cancels out the ability to dive deeper. Within normal trolling speed ranges (1.5 to 3.5 mph), the diving depth of floating lures and devices is essentially the same at respective lead lengths. It is however important to note that although trolling speed may not influence the diving depth of lures and devices, it can influence the “action” and therefore monitoring details like trolling speed is critical to fishing success."

[brigeton]

I believe as stated that speed does not affect crankbait depth over normal trolling speeds. However I'm not sure about cranks trolled extremely slow like 1mph. Depending on lure it may not have enough action to make it dive properly.

I recently emailed Mark Rominak because I was trolling in December with the water around 35° using the 50/50 method and wanted to go around 1.25mph. He said he had other requests for the same data and in the future was going to test lures at 1.25.