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Swamping/Submarining Advice?

Stuart DeSpain

Stuart DeSpain

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Seattle, WA
I’m new to owning a pontoon boat so still getting my “lake legs” under me.

Today I was out on my Bennington GBR 2250 at close to max capacity. I was boating through a cut between two lakes at around 7kts. I was distributing the weight reasonably well but a couple times, while behind another boat, the bow was pulled down and a lot of water swamped the deck. I guess this is called “submarining”.

I had everyone move to stern and turned around as I was concerned the choppy lake conditions weren’t conducive to safe boating. My passengers weren’t entirely thrilled but – even with PFDs on - I was not taking chances.

I’m looking for advice on how to better manage such conditions in future. For example, how alarmed should I be? The final swamp was severe enough to lift the prop out of the water. That seems serious to me but, being new, maybe that’s just me being paranoid.

How do others manage submarining? I read that hitting the wave at 45-30° helps as does working the throttle but both options would have been hard to execute in the cut.

Thanks for your wisdom and advice!

PS - boat and load specifics:
24’ GBR 2250 with two pontoons, 70hp Yamaha outboard; max load is 1487lbs (engine weight accounted for).

This outing had six adults and one child. Some adults are heavy (myself included). With gear I’d estimate that we were tipping 1300lbs. Weight was distributed with two adults at stern, two midship, and two in the bow. Heavier adults were towards the back. Child was, as children will be, free-roaming.

The Montlake Cut is a very narrow passage from one lake to another. It’s generally ~30ft deep with some shallow parts. It’s about 100’ wide at the narrowest point. Boat density is high, with around 20 or so boats passing through the cut with us. This results in lots of water churn bouncing off the concrete walls. Boat density makes it difficult to attack waves at any angle as there is limited room for maneuvering; same goes for acceleration.

The wake that first swallowed us was created by a wide and low ski boat. It was going slow but left a very deep, wide wake behind it. The second submarining was just the result of a lot of crossing wakes from folks coming in a little too fast.

I hope the context helps folks see the situation. Here’s a picture that’s pretty representative of the cut:

montlake-cut-swittersb-seattle-boats.jpg
 
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Head the boat into an oncoming wave at a 45 degree angle and very important don't decelerate as you reach the wave as that will make the bow dip down
 
Keep weight in the back, and approach as link said. Depending on toon configuration you can get the bow up to give some extra distance between the deck and the waves.
 
With that many people on board, you as the captain should assign seating. The heavier people should be seated from mid-ship to aft. Be sure to use politically correct terminology, "I think you would be more comfortable sitting over here", not, "OK I'll need all the heavy people to sit over here otherwise we might sink." I agree with Link, but might add that you can accelerate somewhat into and through the wave. I have been boating for many years and for whatever reason it does seem to happen once a year.
 
As captain, you are responsible for the safety of your passengers so I agree with your decision to return to port. With regard to a pontoon, rough water while heavily loaded can very well produce the results you encountered and as you learned, should generally be avoided.
 
What did you mean by close to capacity? Do you have 2 or 3 tubes. What size motor? These are all factors.
 
You can also trim up to between 1/2 and 3/4 mark, to bring the bow up a little, if you are going faster than just above idle. At 3000 RPM and more, the boat will most likely respond to the trimming of the motor. It still might not help, though, if you are loaded in the bow area.

You also need to figure out where "enough is enough", kicks in. These people that you invited on your boat, were obviously not strangers, so you should have know that there were some that would tip the scales (pun intended), and make the boating adventure less than enjoyable. Next time, you'll most likely know not to invite everyone on one boat outing.

BrumxrUIYAAwmZF.jpg
 
cwag911 said:
What did you mean by close to capacity? Do you have 2 or 3 tubes. What size motor? These are all factors.
Click to expand...

I added a postscript with additional details. I hope they help clarify. If not I’d be happy to add more info! Thanks for any advice you might offer.
 
Spoiledrotten said:
You can also trim up to between 1/2 and 3/4 mark, to bring the bow up a little, if you are going faster than just above idle. At 3000 RPM and more, the boat will most likely respond to the trimming of the motor.
Click to expand...

This is helpful, thanks. I added more detail in a postscript, above. Distribution was fairly solid IMO but I value criticism.

My trim gauge seems a little wonky. Sometimes, when 100% up, it reads as down. Normal oddity or a call for service?

Also, my max RPM is around 6000. Presumably your advice on 3000 RPM and above stands? We were going pretty slow (3500 RPM) so it may not have helped a lot but it could have made the difference!

Lastly, WRT trim, should I be worried about bringing it up too much? Any concerns around overheating the motor if the prop is too high and/or out of the water?

And, again, thank you!
 
All great advise. As captain, it's your responsibility, your boat, your call has to be safety of passengers. I've had both happen to me unintentionally and I have even "exampled" submarining to new boaters what can happen with uneven weight distribution, throttling improperly, reading the water wrong, not watching the wakes from ALL other vessels in your "operational" area, etc.. they usually don't like it! Scares the hookies out of them!

If a rouge wake comes up behind you, overtakes your vessel and you happen to be traveling at about the same speed as that wake AND you are bow heavy!. If it's big enough it will submarine the bow and more than likely an open air prop. As the wake overtakes you. And lifts your stern out of the water. Best course of action is too reduce speed immediately, shut it down (everybody gets a nice up/down rollercoaster ride) or a corrective angle to absorb the wake properly. Or if you have open water ahead...out run it. And take corrective measures.

I have posted this in the past. And sadly I must again report that a boater passed away this past weekend on Lake Conroe. As a result of a much larger vessels wake overtook a small bass boat with 3 occupants. Boat capsized. All 3 overboard. All 3 had PFD on! 1 died. Not sure if the bass boat was under power or anchored or drifting. From what I've heard neither vessel thought they were close enough to pay attention to what was happening with the other, and how each vessel was affected by the other. They were both obviously wrong. And Lake Conroe is a decent size lake. Neither of these vessels was a pontoon. My point is "Be aware of your operational zone"! "Read" the water. Hit those bigger wakes at a 45 degree. You need to constantly be aware of the 360 degree water around you and how it can affect your vessel. If it's like glass, great. If it's choppy, move that weight around. Balance your boat. If there's heavy boating, rough waters! Don't have MAX capacity on your boat, if you are not comfortable riding that much lower in the water, thus more affected by wakes and rough waters. Easier to get swamped. And if something catastrophic does occur. You as captain MUST maintain composure and know what to do in any situation. And above all keep your guests calm.

I more or less "dance with the water", I can see and feel a rhythm of a choppy lake or even Matagorda Bay. Which is big. Leads out to Gulf of Mexico. You can see and feel the waters on your boat. A rhythmic rocking if you will. I pace my boat at slightly faster pace than that rhythm. I make my boat speed match the rhythm of the waters and go 1 beat faster. I want to lead in this dance. Your ride will even out and be smooth. And you should not have issues. Be aware of wind directions. Your vessel need to be "married" to the water and it's beat...it's pulse. You do that, and the two will be beautiful together. You will never beat mother nature, dance with her on the water as a couple. Like Astaire and Rogers. Above all, keep your head on a 360 degree pivot. Bad things can sneak up behind you quick! Or from port or starboard. And if you ever question your ability in a situation, or it feels "iffy" out there...get to shore! This ain't "Deadliest Catch" and Sig Hanssen ain't the skipper, you are! For Gods sake let's all be careful on the water and be proactive in your decision making. If questions arise...shut her down! And get back to port in a safe manner.
 
That is one busy “cut.” I’m glad we don’t have anything like that on our lake.
 
Sounds like you had too many people onboard and let off the throttle when you approached the wave. Follow Link and Lakelivings excellent advice.......
 
How is that not a no-wake zone???

Sorry, that doesn't help you any, just surprised to see all the white water in that narrow area.
 
that area should be a "no wake zone". very narrow for that much traffic at once. Love the cut. Gorgeous. I see way too much churn for that narrow a pass. And that many boats at once. It will certainly keep you on your toes...and throttle.
 
We are having problems on Lake Fenton with these huge 25 foot plus Wake Boats with big ballast tanks. These boats are creating massive waves that will go right over the front of almost any pontoon and tear docks from their posts. Unfortunately new technology is causing a lot of controversy and property damage. I frequently witness wake boat drivers getting yelled at by other boaters.
 
Wakeboarding waves were bad enough but the surfing wave is a big PITA. I don't mind the pwc anymore.
 
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