Safe minimum depth?

[SPaddock]

For an R25, the specs list a 26" draft. I need to know whether this is the draft of the hull or the draft of the lowest point of the prop.

In other words, what's the minimum water depth you would consider "safe" for an R25?

Thanks,
Steve

 

[Levitation]

Draft is the lowest protrusion, at maximum rated load...
Personally, once I see 4 feet, it is dead slow ahead as lots of things can stick up...

 

[j&lgray]

For the Laurie Ann, I really start watching when the depth is less than 5 feet and take evasive action when it hits 3 feet. But, I have the depth sounder calibrated to give me the amount of water that is under the keel. So, when my depth sounder says three feet, that is three feet of water under the keel, not from the surface. That way, I do not have to any mental math. In my circumstance, when the depth sounder says zero, we are aground.

I hope that makes sense.

 

[commander bill]

I have a special fear of hitting bottom. As such I have 3 separate depth indications (Small cheap digital gauge with alarm, Garmin 3210 with depth, & Garmin 498C with depth). This weekend I picked up friends at a new dock I had not been to before. Tennessee river is usually cloudy and bottom haard to see below 3 feet. I showed 5 foot depth on all 3 gauges at this dock so I got out and used my boat hook to determine actual depth. Indicated depth was accurate within an inch. This is a good way to ontain a better comfort level about your depth indication.

 

[Bay Ranger]

Another thing I've learned, particularly up in your area, is that those thick underwater grasses can give you a false reading on the depth sounder. This summer we got directions from a dockmaster at a marina up you way to pull all the way up the the bulkhead. My depth sounder dropped to 3 feet and we still had 200 feet to go. Needless to say, I was getting nervous. I questioned the dockmaster on VHF and he said not to worry, there was 7 feet all the way in. The weeds were giving us a false reading!

We have also encountered shallow spots going down the ICW where we were watching the depth sounder very closely. Then a huge boat goes by in a narrow stretch, stirs up the mud or sand on the bottom, and our depth sounder goes wacky for a minute or so. That's all we "depthophobes" need to give more gray hair!

 

[doke01]

The prop does not extend below the keel. It is up in a nice little prop pocket. We have been in water that indicated 2.3 feet deep from the waterline many times with no issues. Although we made sure we were making the least amount of headway possible since even a little bit of speed will cause the stern to drop down.

Also found that in water less then 6 feet the trim tabs should be trimmed down a lot farther then in deeper water to give you the most efficient ride . I don't know if that is just us but we were having trouble getting over 9 knots in the NJ ICW at about 5 feet so, out of desperation, I dropped the trim tabs further then normal and she sped right up to cruising speed around 12 knots. I think the prop wash was pushing against the bottom and creating turbulence that slowed the boat down.

 

[commander bill]

I have also been told that extending trim tabs fully in shallow water can provide you with a small amrgin if you rub bottom. The tabs rub first - you stop - raise tabs - back the hell up. Never tried it. Would someone else try this and let us know if it works. Then I will find out how smart my friend is.

 

[captain's cat]

I have also been told that extending trim tabs fully in shallow water can provide you with a small amrgin if you rub bottom. The tabs rub first - you stop - raise tabs - back the hell up. Never tried it. Would someone else try this and let us know if it works. Then I will find out how smart my friend is.

Probably true Bill BUT, if you forget step 3 (raise tabs), you'll leave them on the bottom, scraped off the boat! by backing them into the bottom 🙁

That's not a good practice. :!:

Best not to violate Lindsay's Law* at all.

Charlie

*Lindsay's Law states "When the draft of your vessel exceeds the depth the water, you are most assuredly aground!"

 

[doke01]

This won't work. The trim tabs move a lot less then you expect and don't drop lower then the prop/keel. It works much better to have everyone move forward and to the same side of the boat. It lifts the prop and shifts the keel to the side.

 

[RProffer]

If you are aground, and all else fails, turn off the engine and just have everyone jump out of the boat. If you are lucky, that should float the boat enough so you can push it off the bottom. Be sure to check the hull for gouges and holes, and check the skag and prop, and check the through hulls for security and mud. Mud in the through hulls will overheat an engine quickly.

Oh, and you might want to have hold of a bow or stern line before you push the boat off the bottom.

 

[captain's cat]

If you are aground, and all else fails, turn off the engine and just have everyone jump out of the boat. If you are lucky, that should float the boat enough so you can push it off the bottom. Be sure to check the hull for gouges and holes, and check the skag and prop, and check the through hulls for security and mud. Mud in the through hulls will overheat an engine quickly.

Oh, and you might want to have hold of a bow or stern line before you push the boat off the bottom.

And if you are aground at the bow and the stern is still in deep water, jump off the bow, not the stern! Don't ask me how I know.... :?

Charlie