brand new to idea of scooters

[Angelo Farina]

He had knee replacement surgery. Since then, the knee will not straighten out all the way and the leg is weak. He has done lots of PT and at home exercise, but with very limited results.

Ok, so there are two problems:
1) limited excursion of the knee articulation, impeding to extend the leg entirely
2) limited muscular strength, impeding to exert strong force against water resistance.
The first point could require changing the angle between the fin blade and the foot pocket. Most fins have a negative angle, ranging between 10° to 25°. This is for accommodating the limited extension of the ankle articulation of most people. Competitive free swimmers, instead, have an exacerbated mobility of their ankles, due to years of swimming with fins, hence they need fins with positive angle (such as the Force fins, and a few others).
A good finned swimming instructor should check the movement of the leg(s) of your husband and provide guidance on the choice of fins with proper geometry, and on the kicking style for employing them properly, without stressing articulation and muscles.
If the two legs have different mobility, this could well results in using DIFFERENT fins on the two feet...
The problem is that the people usually dealing professionally with rehabilitation after surgery have a proper understanding on the mechanics of walking or running, but little or no understanding on the mechanics of swimming or fin-kicking.
Albeit generally speaking all the rehabilitation done is good for improving the strength of the muscles, possibly the exercises practiced are best suited for improving walking and running, not swimming.
But for this only professional rehabilitators can help. And there are limits to the maximum force that these muscles can reach after surgery.
So, coming back to my experience with athletes, what you can do is to change the "gear ratio" of your husband's fins. I usually make the comparison with a bicycle equipped with variable transmission. Some people perform better with a low cycling rate, and exerting a strong force on pedals. Others are better suited with a shorter gear ratio, which requires a faster rate, with smaller force.
The resulting power (which is proportional to the product of the rate and the force) reaches a maximum when the proper rate-force balance is attained, but this maximum is strongly dependent on the capability of each individual, which, of course, fades with age and with health problems.
So, it is advantageous to experiment changing the other two parameters of the fins employed (length and stiffness), until the optimal conditions for your husband are found. But also doing this, hence maximising the power delivered, still the result could not be enough for very strong currents.
Only at this point you need to employ the scooter, for adding the missing power.
Resuming, the path for me would be:
1) find the optimal blade angle for each of the two fins (possibly different on the two legs).
2) find the optimal "gear ratio", changing length and stiffness of the fins
3) training for a proper kicking style depending on the anatomical limitations and the geometry of those "optimal" fins
4) evaluate if after all these optimisations the power delivered is enough, or not
5) if the result is still not enough, then go with the scooter.

 

[jomcclain]

Ok, so there are two problems:
1) limited excursion of the knee articulation, impeding to extend the leg entirely
2) limited muscular strength, impeding to exert strong force against water resistance.
The first point could require changing the angle between the fin blade and the foot pocket. Most fins have a negative angle, ranging between 10° to 25°. This is for accommodating the limited extension of the ankle articulation of most people. Competitive free swimmers, instead, have an exacerbated mobility of their ankles, due to years of swimming with fins, hence they need fins with positive angle (such as the Force fins, and a few others).
A good finned swimming instructor should check the movement of the leg(s) of your husband and provide guidance on the choice of fins with proper geometry, and on the kicking style for employing them properly, without stressing articulation and muscles.
If the two legs have different mobility, this could well results in using DIFFERENT fins on the two feet...
The problem is that the people usually dealing professionally with rehabilitation after surgery have a proper understanding on the mechanics of walking or running, but little or no understanding on the mechanics of swimming or fin-kicking.
Albeit generally speaking all the rehabilitation done is good for improving the strength of the muscles, possibly the exercises practiced are best suited for improving walking and running, not swimming.
But for this only professional rehabilitators can help. And there are limits to the maximum force that these muscles can reach after surgery.
So, coming back to my experience with athletes, what you can do is to change the "gear ratio" of your husband's fins. I usually make the comparison with a bicycle equipped with variable transmission. Some people perform better with a low cycling rate, and exerting a strong force on pedals. Others are better suited with a shorter gear ratio, which requires a faster rate, with smaller force.
The resulting power (which is proportional to the product of the rate and the force) reaches a maximum when the proper rate-force balance is attained, but this maximum is strongly dependent on the capability of each individual, which, of course, fades with age and with health problems.
So, it is advantageous to experiment changing the other two parameters of the fins employed (length and stiffness), until the optimal conditions for your husband are found. But also doing this, hence maximising the power delivered, still the result could not be enough for very strong currents.
Only at this point you need to employ the scooter, for adding the missing power.
Resuming, the path for me would be:
1) find the optimal blade angle for each of the two fins (possibly different on the two legs).
2) find the optimal "gear ratio", changing length and stiffness of the fins
3) training for a proper kicking style depending on the anatomical limitations and the geometry of those "optimal" fins
4) evaluate if after all these optimisations the power delivered is enough, or not
5) if the result is still not enough, then go with the scooter.

Thank you

 

[geoff w]

He had knee replacement surgery. Since then, the knee will not straighten out all the way and the leg is weak. He has done lots of PT and at home exercise, but with very limited results.

Getting old really sucks! I had knee surgery a couple of years ago for a torn meniscus, and even though I'm mostly fine my repaired knee is really only about 85% as good as before. But I still dive a lot, mostly So Cal beach dives, with surf, so I tend to be a little more careful going in and out through bigger waves, with or without a scooter. Scooters definitely make surf entries different, sometimes much easier, sometimes not.

I took a PADI DPV class a long time ago. Scooters are one of the most fun things you can do underwater, and definitely inspire confidence with current. But one of the biggest lessons from the class was don't go diving with a scooter anywhere you can't get back if your scooter craps out. If it does die, you not only have to get yourself back, but your scooter as well (unless doing so endangers you, in which case your scooter is expendable, just like ditching weights in an emergency).

Not quite 2 years ago a bunch of friends and I bought Dive-X Blacktips shortly after they came out. For an under $2K scooter, it's incredible, and can definitely hold its own with much more expensive scooters. It's also relatively light at 24 lbs. They are not perfect, and have some quirks, but you can't go wrong with the Blacktip. They also occasionally have problems, so re-read my previous paragraph. They are easy to travel with, and can fit into a Pelican case, but you need to hand carry the batteries on airplanes.

One friend wanted something smaller and bought a Subgravity Aquaprop. It cost more than a Blacktip with batteries and is much less capable, but it is about 10 lbs lighter. On beach dives he doesn't notice carrying it. It's well made, but also has it's share of issues.

Another friend bought a couple of Scubajet scooters. I haven't seen it, but from what I've heard from him, it's very limited in terms of capability, and also costs more than a Blacktip.

My niece's boyfriend bought her one of the Lefeet scooters. I'm not sure if she used it yet. Like the Scubajet, I personally wouldn't use it in anything more open water than a swimming pool.

Given how popular the Blacktip is (Dive-X priced it low, offered lots of capabilities, and I think they were completely surprised at demand), my suggestion would be to go on the Dive-X Facebook group and see if there's someone near you willing to go out for a demo dive so your husband can try one out. There are Blacktips everywhere now, and one of my two biggest surprises with mine is how many new friends I have made because of owning one. The Blacktip community is very friendly and supportive.

 

[AJMcc]

I was actually looking at the ScubaJet, but would need something that can be made neutrally buoyant. Contact scubajet and they said that they don't have anything to make it neutral.

Hi,
Not sure how far off neutral The ScubaJet is but if it's not too far off, I use Syntactic foam to adjust my camera rig, make strobe arm floats and to trim out my DPV after a battery upgrade. You can buy it in 12"x12"×1" sheets, easily configurable. Just an idea, if your into a little DIY, could solve a problem.

Best of luck in your quest and dont pay any attention to the detractors.

Dive safe.
Anthony

 

[NothingClever]

 

[inquis]

Since it's minor assistance you're looking for, the Lefeet S1 looks pretty attractive in that role. I can't imagine any boat having issues with it as slender/small as it is. At 5 lbs, he might choose to exit with it, or you could take it from your husband at the stop and clip it to yourself. (No crew assistance either way.) A bonus is it can be paired with a second unit if more thrust is desired. (Disclaimer: I have no personal experience with it.)

Edit: haha, guess @NothingClever had more coffee than I did this morning.

 

[NothingClever]

Since it's minor assistance you're looking for, the Lefeet S1 looks pretty attractive in that role. I can't imagine any boat having issues with it as slender/small as it is. At 5 lbs, he might choose to exit with it, or you could take it from your husband at the stop and clip it to yourself. (No crew assistance either way.) A bonus is it can be paired with a second unit if more thrust is desired. (Disclaimer: I have no personal experience with it.)

Edit: haha, guess @NothingClever had more coffee than I did this morning.

You’ll beat me to the punch tomorrow. Today was my lucky day.

I’m thinking a pair of this Lefeet scooter would be perfect for @jomcclain and her husband.

I respectfully think the BlackTip would be overkill.

 

[SmashMonkey]

I know nothing about DPVs but I was surfing YT and came across this device by Aqua Beyond and thought of OP. At first I checked the post date to see if it was April 1.