Outboard depth in water

[FFMDiver]

Are depths on outboard motors standard? If so how deep do they sit? If not, how deep is the deepest you have seen? Not that I intend to dive near boats, slips or marinas, but I will be in a popular area that is shallow looking for artifacts. (with a dive flag of course). And we all know how much we trust boaters...

 

[String]

No standard. Depends on the draught of the hull, the size of the engine, the design of the hull and many other things.

If the boat isnt planeing it SHOULD be the bow that hits anything first anyway.

Standard RIB shouldnt really be more than 1m (3ft) though.

 

[seaducer]

Shaft lengths are fairly standard, but there are short shaft and long shaft motors. Mostly the difference will be the way the boat sits in the water. Some draft deeper than others.

 

[String]

Speed has a factor too if its not a displacement vessel. At high speed or on the plan it'll be not a lot more than the prop in the water. If its slow speed you've got the entire hull.

 

[Nemrod]

Shaft length is 15/20/25 I think. Most V hull boats have the long shaft. The depth of my BW at idle is 15 inches I think to the keel plus about 15 more for the lower unit.

Uh, I would be very careful about diving in shallow water under moving boats--propellers will cause devastating wounds or fatalities.

I would not want less than 15 feet depth for outboards and small outdrives, I do not want to be under a moving 40 footer in low viz without at least 20 feet. Why, becuase you could get preoccupied with a treasure and wind up pretty quick in a prop. The larger the boat the more water they move

I got sucked up from the bottom under a tug once, fortunately, it is a long story, I was pushed to the surface behind the boat. I could hear those props really close.

Never--ever--attach your flag to your body--NEVER--EVER.

N

 

[Papa_Bear]

I have a transom jack and can send in all the way down or bring it almost out of the water and each position has a different use! I would be careful about diving around boat traffic and tow a diver down flag! BTW a boat not trimmed has its bow OUT of the water and you would get hit by the center of the boat and then the prop! Boat traffic and divers don't mix! It's like picking up cans on the freeway!

 

[bfw]

The depth of an outboard prop is relative to the draft of the boat. The prop has to be below the hull. The draft of outboard boats varies - outboards are used for everything from an inflatable dinghy to a forty foot fishing boat that draws 3-4 feet. How shallow is this water? If you're hugging the bottom, most boats that pose a hazard to you won't be in such shallow water unless the operators are fools; because they risk grounding. The fastest boats are jetboats, which hardly draw any water.

 

[Gary D.]

If the boat isnt planeing it SHOULD be the bow that hits anything first anyway.

If the boat IS idling or planing it MAY be the bow that strikes first. But if it is somewhere in between, as in a plowing angle, it could very well be the stern, drive or prop that makes the first strike and not the bow.

Gary D.

 

[LeadTurn_SD]

I would not want less than 15 feet depth for outboards and small outdrives, I do not want to be under a moving 40 footer in low viz without at least 20 feet. Why, becuase you could get preoccupied with a treasure and wind up pretty quick in a prop. The larger the boat the more water they move

Exactly what Nemrod said. I'm a boat owner, diver, and ex-Merchant Marine Officer. I'd want at least the depths Nemrod mentioned, and in fact I'd still be pretty nervous.

Stay Safe!

 

[String]

If the boat IS idling or planing it MAY be the bow that strikes first. But if it is somewhere in between, as in a plowing angle, it could very well be the stern, drive or prop that makes the first strike and not the bow.

Gary D.

A lot depends on hull shape. I guess some areas have flatter and less draught (ie calmer water designs) than others.

Certainly when ours hits something planing its the stern hull that usually takes the hit not the leg.

Either way if any part of the boat hits you its going to hurt regardless of if its the prop,leg or hull especially if its doing any speed at all.

So stay deep, tow a marker and ideally dive when there is little boat traffic. Or best bet get someone to act as boat safety cover to shield you by putting their boat between your marker and the oncoming vessel.