Under Water Prop Change

[TeamAllen]

There was a thread posted back in 05/05 that questioned changing propellers underwater. I found this simple piece of diving equipment, that looks like, would get the job done. It is small and is able to be refilled. The cost is $195.

I think it would be well worth it if you frequent large lakes like Powell and Mead. If I am an hour up river, I can't imagine the time lost in either limping home or having to be towed back.

Like all diving equipment, you need to be properly trained and certified.

Scuba.com
http://www.spareair.com/

[raythompson]

Air Supply is not the problem

My biggest concern would be dropping parts, not air supply. Drop the prop nut, the wrench, the prop puller, or worse the prop itself. The cotter pin is probably the only non-critical part that you could loose.

[TeamAllen]

Ray, you were the one that posted the thread I referenced. That's cool!

I think I would get the boat near the shore, bow pointed out so you are only a few feet deep. I thought of like a stretchy lanyard for the tools. Maybe a rope for the prop. There should be spare parts in the prop romover kit, just in case.

I have removed a rope before tangled around the prop shaft. I just used by mask and it was very difficult. There is no way you could replace the prop without some sort of breathing device.

I thought of a big long breathing tube, but some people said we don't have enough lung capacity to completely exhale the tube each time. Therefore, you would just be breathing back in your exhaled air. Not good!

[talltigeguy]

If you take the swim step off and have really long arms, you might be able to do it.

[gcope63]

I have a couple of friends that have these for backup air when they are scuba diving and they work pretty good!, pretty good supply of air for the size.. I think the tethered tools, shallow water and the spare air should make it doable.. The one hassle with the spare air is getting it refilled, especially if you don't scuba dive and have a repore with the local dive shop... There's been a few times I wish I had one for a prop change!!

Gary

[raythompson]

Having munged some props quite badly, including a stainless prop on an outdrive, I have never done so badly as to not be able to limp home at 5 mph. Yeh part of the day is shot. But I would much rather take the boat back to the trailer, load, then replace the prop. Even if you could not drive the boat you can get a tow from some other boat. But it would be very rare that you could not make some forward progress as that would require the majority of the blades to be bent completely in the opposite direction.

You would have to use shallow water to replace the prop. The weight of the prop and tools would more than offset human boyancy in water and you would soon head to the bottom of the lake. You would have a difficult time getting under the boat with a PFD. If you don't think so take a spare propeller to a swimming pool. Float in the water and have someone had you the prop. You will sink to the bottom.

Even in shallow water (you would need at least two feet) dropping the prop nut would produce a real problem. For a test find some water, colored like lake water, and a soft bottom. Drop the equivalent of a prop nut and then try and find it. You will have to use your hands as the silt kicked up would make visibility zero. It is not as easy as it sounds. You could probably find the wrench, and certainly the prop, but the nut would be a different matter.

If you had the boat in that shallow depth of water, say about two feet, you could use a hose to breath. You certainly have enough lung power to exhaust three feet of hose and pull in fresh air.

I still consider trying to changing a prop while the boat is in the water an excersize in frustration and frought with difficulties. I would rather limp home than eliminate all possibility of movement completely and disable the boat by loosing a critical component. Gearing ones self up with the necessary components is a false sense of security that may put ones self in a more difficult situation.

I don't even carry a spare prop on the boat or in the truck. If I loose a prop the day is done and I go home. I can replace the prop in my driveway at a liesurely pace and be assured that the job is done correctly.

I have been boating for 28 years and used to carry spare parts such as plugs, points, fuel line, fuel filter, wrenches and other tools. In that 28 years I have never used the spare parts once. I have never needed the tools. In fact I have never been completely stranded requiring a tow. I have severely damaged props four times and been able to get home under my own power.

[TeamAllen]

Gary, I think it will work also. The kit comes with a yoke refill adapter, so you can refill it yourself from a larger tank. The best thing about it is, it's size. It won't take up that much room in the boat.

It is cheap insurance, if I am prepared for a problem, it will never come. Normally, I wouldn't bring a spare prop on board when I will be on a smaller lake near my trailer. But Lake Powell or Mead? Definately!

Sorry tall, I don't think my arms are as long as yours. I don't have the removable swim step either. That is a good idea though.

[Tequilasun]

Well, I have changed a prop on the water. I would much prefer to do it Ray's way though, limp in etc. It is certainly not fun. I did have a mask, but no air canister. I was also a lifeguard and competitve swimmer at the time so holding my breath for a minute plus really wasn't a big deal. It did take a heck of a lot of dives, and a really long time.

I was certainly worried about losing parts, I kept them cliped to a life vest when not using them, and clenched them tight when moving them around. I was in about 6 foot of water and probably would have been more confident had I had one of these:

Big Magnet

[johnbandrews]

Three years ago at Lake Powell, I too changed a prop in the water. Like draginass says, it was no picnic, but doable. We were in pretty clear water, I used a face mask, and was VERY careful with the parts. Other than the 20 or so dives holding my breath, it really wasn't that bad. Best on a trailer, but when you're 20 miles from the nearest marina, you do what you have to do.

[TeamAllen]

Good idea about the magnet. A little extra ballast too.

I would probably limp home if my trailer was 20 min. away. Just being 20 min. from a marina won't help. It has to be the marina where your trailer is. We are usually 1 hour from the marina we launch from. That is @ cruising speed. If I had to limp back? Wow!

It is encouraging to hear it has been done.

[Wake Havasu]

I would limp to the closest shallow cove where I can sit down while changing the prop with my spare air!

[Wake Havasu]

[i] The one hassle with the spare air is getting it refilled, especially if you don't scuba dive and have a repore with the local dive shop...
Gary [/B]

Why?
Do Shops not recognize this device as being sound?

Or

Is it that a non certified diver is trying to refill it?

These devices would be great ideas for tall building fire escape as well!

[raythompson]

Originally posted by TeamAllen It is encouraging to hear it has been done.

Along with a spare prop you should consider carrying a spare prop nut and two of shaft keys. A couple of stainless steel cotter pins would be nice (nothing will ruin your day like spinning your prop off the shaft.) These are the parts that are easiest to loose in the water. And before you change the prop rotate the shaft so the key slot is up before you remove the prop. Also carry some marine grease (the heavy green stuff) and put that on the shaft before you install the prop. The grease will help the shaft key to stick to the shaft.

[my86stanggt]

I wrapped a tube rope around my shaft in 200' of water and close to cliffs. I was drifting toward the cliffs not shallow water. My and the wife had to dive repeatedly with a good knife to get the rope free. The spare air is a good idea. It took me over an hour to get that rope free, with the air it would've been alot quicker. I had my kids pushing the boat away from the rocks to keep from banging against them.

[zany]

As far as dropping parts and tools in the water, you just need to provide something for the parts or tools to fall onto.

In shallow water put a large towel on the lake bottom under the prop and put rocks on the corners to keep it from moving.

In deep water tie ropes to the corners of the towel and hang from either side of boat, put a rock or weight in the center of the towel to keep below the boat and prop.