Oops! Ran aground, ...now what?

[KnotConnected]

So I was trucking right along at ~23MPH, happy as a clam on Saturday, when the depth went from about 28' to 1.5' in a real big hurry. I noticed the boat stop so I powered down to neutral immediately, but the deceleration was enough to send my buddy on the back seat forward into the deck table. Luckily it's all sand and muck around here, so the landing was pretty soft and I don't think anything shredded the hull.

After freaking out a little bit, and trying to power out of it with 1/2 - 3/4 throttle to no success, I trimmed the Bravo3 all the way up (props ALMOST out of water) and was able to slowly push out in forward idle & turn around.

I came back in the rest of the 15 minute trip at WOT without noticing any large vibrations or any other obvious problems, but now that I'm back at the slip safely is there anything I should check / look out for?

Also, in the future, whamming on the throttle to force my way out PROBABLY wasn't the best idea, right? And, is it safe to trim the Bravo-3 up while the engine is running, or while forward / reverse is engaged? I thought I read somewhere that you shouldn't trim the out-drive while underway.


Thanks!


(P.S. lesson learned, I'm NEVER cutting it close to the channel markers again)

1994 Larson Cabrio 280 | Single 7.4 Merc | Bravo-3 | Green Bay, WI

 

[cobra1476]

Re: Oops! Ran aground, ...now what?

Hmmmm......Sounds like what I did 6 years ago.

I also was in a Larson and it probably was in the same exact spot.

When coming back in the bay you never want to go to the left of the "bird island". That gets very shallow fast.

In regards to the boat, it should be fine. the sand is soft like mud.

 

[Splat]

Re: Oops! Ran aground, ...now what?

I question why you were doing 20+ mph in a channel...

I would inspect the prop for damage. Also I would put a mark on the prop hub and take it out for a ride then check to make sure the hub hadn't slipped. It sounds like you didn't hit anything with the prop though.

Also I would inspect the hull. Look for cracks, deep scratches, holes, also check any thru hulls for damage. It may have been sandy with some rocks mixed in.....

Finally running the motor with the out drive trimmed all the way up is bad on the u joints. Even with the transmission in neutral those u joints are always spinning. You probably didn't damage it, I just wouldnt make it a habit of doing it all the time.

Must of us have gotten into skinny water at least once in our day, sounds like you probably got lucky. You'll know better for next time. Don't sweat it to bad.

 

[H20Rat]

Re: Oops! Ran aground, ...now what?

Its fine to run for short times at minimal idle with the drive up. As long as you are still submerging the water intake grates at least.

 

[cobra1476]

Re: Oops! Ran aground, ...now what?

BTW, I just notice that your boat is a 280. that 28" right? how the heck did you get it out of there. I had a 18' and it was a pain to get it out.

 

[KnotConnected]

Re: Oops! Ran aground, ...now what?

Thanks Guys! Everyone's been saying to trim way up while going to anchor in the shallows of the sandbars, so it's good to know it's safe to trim up a touch with forward idle / minimal throttle.

I'll Inspect the hull, the props, and check for slippage. I appreciate the pointers Splat! The channel is a *large* shipping channel through an otherwise large but shallow bay. I'm always one of the slower boats out there running at 23MPH.


Cobra, yeeip. I was just inside of the red cement channel marker off the tip of long-tail. Looking at the charts, that marker *clearly* needs its space..

http://i46.photobucket.com/albums/f117/n915aa/Whoops_zpsec6d3cdd.jpg

 

[Natty Light]

Re: Oops! Ran aground, ...now what?

I have done the same thing as I imagine most have. The only thing I would have done differently would have been to walk the boat out instead of powering. You can also have passengers sit on the bow to lift your lower unit as high as possible from the bottom.

 

[Splat]

Re: Oops! Ran aground, ...now what?

Ah OK. Very good. When I hear channel I think of small channels in no wake zones. The majority of what we have around here in Ohio. Running aground, is like guys that drop motorcycles, those that have and those that will.

 

[skydiveD30571]

Re: Oops! Ran aground, ...now what?

Thanks Guys! Everyone's been saying to trim way up while going to anchor in the shallows of the sandbars, so it's good to know it's safe to trim up a touch with forward idle / minimal throttle.

That's the thing though, it may be ok once but it is not safe to do it repeatedly. It will eventually cause u-joint failure. Your manual will tell you how high you can safely trim up while at or above idle speeds.

Also keep a close eye on your temperature in the near future. You can bet you sucked up some sand and mud when the drive was in it, especially when mashing the throttle because that impeller creates a lot of suction power at high rpm's. It may have cleared out just fine, but it's not uncommon for dirt and debris to clog a t-stat housing or exhaust outlet and cause an overheat situation.

 

[KnotConnected]

Re: Oops! Ran aground, ...now what?

Natty,

yeah my neighbor at the marina said "well, if you were in a foot and half, why didn't you just jump out and push?" a perfectly logical thought that never came *near* crossing my mind in the panic..

 

[cobra1476]

Re: Oops! Ran aground, ...now what?

Ah OK. Very good. When I hear channel I think of small channels in no wake zones. The majority of what we have around here in Ohio. Running aground, is like guys that drop motorcycles, those that have and those that will.

Our channel here takes huge ships.. I'm taking 700' and up. Lol!

 

[shrew]

Re: Oops! Ran aground, ...now what?

I question why you were doing 20+ mph in a channel...

I would inspect the prop for damage. Also I would put a mark on the prop hub and take it out for a ride then check to make sure the hub hadn't slipped. It sounds like you didn't hit anything with the prop though.

I don't see that the OP mentioned he was in a channel, though there are plenty of channels wide enough to allow for greater than headways speeds.

Also, there are no prop hubs on a Mercruiser Bravo 3. It is a SS prop and a SS prop shaft and splines, with SS gears and bearings. Either nothing gets hurt, or teeth on the something get sheared.

If the teeth on the drive gears get sheared the drive will start sounding like a coffee grinder. You'd have to pull the prop to inspect the prop splines and prop shaft splines. Most of this occurs when the drive takes a direct hit.

This sounds like a soft, gradual landing where the keel slowly started digging into the sandbar.

If you can ground the boat, you can typically get out and push it off as you're probably in less than waist deep water.

 

[Toddavid]

Re: Oops! Ran aground, ...now what?

If your prop was buried in the sand/muck, you may want to keep an eye on your water temps. You could have sucked up enough abrasive debris to damage your impeller or score its housing.

Been there, done that, and thankfully got away with it. But I opted to walk the boat off the sandbar rather than power through it trimmed all the way up.

 

[KnotConnected]

Re: Oops! Ran aground, ...now what?

If your prop was buried in the sand/muck, you may want to keep an eye on your water temps. You could have sucked up enough abrasive debris to damage your impeller or score its housing.

Been there, done that, and thankfully got away with it. But I opted to walk the boat off the sandbar rather than power through it trimmed all the way up.

Is there any way to clean the cooling system of debris or check for proper flow rates while it's safe at the dock? I'm taking a ~60 mile trip up north for Labor Day (big trip for me. first time) and would ideally like to be as proactive with everything as possible. Would it be worth it to check the impeller? (Does the sand mulch up the impeller or stick around in the impeller housing?)

 

[Toddavid]

Re: Oops! Ran aground, ...now what?

I am a trailer guy, so I am not sure what the procedure would be to pull the impeller while in the water. I think you are below the waterline on your engine (could be wrong) so pulling the impeller while in the water would be a potential sinking issue?

Yes, sand is very abrasive and can grind away both the impeller and the housing, especially the brass housings. Did you watch your gauge when cruising back at WOT to the dock? Another spin around your local waters while watching the gauge may be your next step, other than pulling the boat to do an impeller check (or finding out how to do it in the water). How old is your impeller anyway?

 

[KnotConnected]

Re: Oops! Ran aground, ...now what?

Replaced the impeller this spring. It's a little effort to crawl into the engine room and monkey with it, but not too hard to pull off. I was just wondering if i DO get it off and everything looks clean / good, can I assume the cooling system is clean? or could I have sucked up all kinds of nasty junk that'll destroy stuff without ever having any signs of damage in the impeller housing.

 

[southkogs]

Re: Oops! Ran aground, ...now what?

If you know where your incoming water line is - coming up from the impeller - you can just unhook one end and inspect. That'll suggest if you have muck running up your line.

 

[Home Cookin']

Re: Oops! Ran aground, ...now what?

A lot of worrying here over a minor event that is often part of a day's boating on the coast. Well, maybe not hitting that hard daily but we've all done it at least once. It's certainly typical to be running in sandy bottoms and bumping occasionally, and to stir up the bottom at low speeds. A sudden hard sand hump is a bad thing but a gradual rise to shallow over a flat is typical. With experience you can feel and hear the difference. You also learn how to run on a plane over water you couldn't at slow speed.

First, SS props do have hubs, unless you have a specially made prop that doesn't. I'd call that a design flaw.

Second, boaters don't jump overboard except as a last resort*; there are many skills and tools to deal with shallow water and running aground. Sometimes you have to. In the summer you might not mind; duck hunters feel differently about that approach. Not to mention that you may get into deep water, currents, a drifting-away boat, etc. There are plenty of sandbars with sheer drop-offs of over 10'.

Attempting to back off at low power and tilted up is the first thing to try. Keep in mind that it stirs up a lot of sediment (more on that later) and you don't have a skeg protecting your prop.

Third, there is no need to worry about sucking up sand/silt on your one run-aground. Whatever you sucked up, you flushed out on the way home. Nothing was hurt. If you run in sandy muddy water all the time, then yes you do need to change your impeller once a year. So don't go tearing your LU apart or other parts just over that one time. You can have black water come out the telltale then go run in some seawater and be fine. I think it's best to keep it moving rather than let it settle.

By the way, stirring up the bottom while moving forward is not an issue; you are leaving the stirred up stuff behind you; it's clean in front of the prop.

As you know, channels are not "no wake zones." That was an odd comment; I took it to mean you were going too slow.

But I have to add that my 50 years of low water running is all outboards. There may be things peculiar to an i/o (like the drive system and raising the motor to run) that I don't know adn thus I didn't comment. But I'll say this: if there's risk of damage to your motor from one simple soft grounding, there's no reason ever to buy a motor like that; it's not made for outdoor use.

*Same applies at the ramp.

 

[KnotConnected]

Re: Oops! Ran aground, ...now what?

A lot of worrying here over a minor event that is often part of a day's boating on the coast. Well, maybe not hitting that hard daily but we've all done it at least once. It's certainly typical to be running in sandy bottoms and bumping occasionally, and to stir up the bottom at low speeds. A sudden hard sand hump is a bad thing but a gradual rise to shallow over a flat is typical. With experience you can feel and hear the difference. You also learn how to run on a plane over water you couldn't at slow speed.

First, SS props do have hubs, unless you have a specially made prop that doesn't. I'd call that a design flaw.

Second, boaters don't jump overboard except as a last resort*; there are many skills and tools to deal with shallow water and running aground. Sometimes you have to. In the summer you might not mind; duck hunters feel differently about that approach. Not to mention that you may get into deep water, currents, a drifting-away boat, etc. There are plenty of sandbars with sheer drop-offs of over 10'.

Attempting to back off at low power and tilted up is the first thing to try. Keep in mind that it stirs up a lot of sediment (more on that later) and you don't have a skeg protecting your prop.

Third, there is no need to worry about sucking up sand/silt on your one run-aground. Whatever you sucked up, you flushed out on the way home. Nothing was hurt. If you run in sandy muddy water all the time, then yes you do need to change your impeller once a year. So don't go tearing your LU apart or other parts just over that one time. You can have black water come out the telltale then go run in some seawater and be fine. I think it's best to keep it moving rather than let it settle.

By the way, stirring up the bottom while moving forward is not an issue; you are leaving the stirred up stuff behind you; it's clean in front of the prop.

As you know, channels are not "no wake zones." That was an odd comment; I took it to mean you were going too slow.

But I have to add that my 50 years of low water running is all outboards. There may be things peculiar to an i/o (like the drive system and raising the motor to run) that I don't know adn thus I didn't comment. But I'll say this: if there's risk of damage to your motor from one simple soft grounding, there's no reason ever to buy a motor like that; it's not made for outdoor use.

*Same applies at the ramp.

Thanks dude. Exactly what I want to hear. This is my first summer with the 28' cruiser, which is my first boat, so I'm a little paranoid / anxious as it is, let alone when stuff goes wrong.

Thanks again everyone!

 

[agallant80]

Re: Oops! Ran aground, ...now what?

You have a bravo3 so ignore the advice on prop hubs, you don't have one.
Running aground like you did is not that big of a deal provided you are not running in to stumps and rocks. I would take the boat out before your big trip and pay attention to the temp. If its fine than you are cool, if its not than you will have to inspect your impeller and impeller housing to see if they were ripped up by the sand. It can happen but if you made it back to the dock then I would say you are fine.