Pontoon Boat Backwash

gdgdad

Recruit
Joined
May 26, 2016
Messages
2
I have a Sweet Water 2080 pontoon (i.e. 20') and we boat the gulf. I get excessive backwash while underway - so bad it would flood the chnage room (head) area and drenches everything within 2 feet of the rear of the boat. Bought this boat new 2013. 70 hp Yamaha. Any ideas what causes this and what to do?
 

H20Rat

Vice Admiral
Joined
Mar 8, 2009
Messages
5,199
Motor mounted too low or trimmed down too much. (or both) The vast majority of pontoons are rigged with the motor just dropped on the transom, when it could actually be raised up some for much better performance.
 

frantically relaxing

Senior Chief Petty Officer
Joined
Nov 19, 2011
Messages
699
Not sure what you have under yours as a partial 3rd log, but here's a shot under our Party Cruiser. Note the partial log in the back. Also note (look hard) the M bracket. Note it's solid from front to back, and it's wide open towards the front. The back of the log, and M bracket, are butted up against the transom... so guess what happened while underway? The M bracket makes a perfect water scoop, and once the water hits the transom, it wants to get OUT. And if you opened the battery box door under the bed in back while underway, you were treated to an upside-down wall-of-water! The water literally shot straight up and onto the floor! Just driving the boat would soak the back carpet...Everybody with one of these knows what I'm talking about!

The fix was simple, I just filled up the M bracket space with spray foam and sawed it off flush :) -- never had a wet floor again!
SO, whether you have a setup like mine or not, I don't know, but ANYTHING under there in the middle can cause water to spray upwards, and that'll end up in your boat...

PCtoons.jpg
 

gdgdad

Recruit
Joined
May 26, 2016
Messages
2
Thanks for all the feedback! On the engine mounting, I've always thought it may be mounted to low and at the same time they cantilever the engine out far past the logs to increase deck space. I was concerned raising the engine would raise the bow even more when at rest. As far as possible water in the logs - how would I check / test that? They're in great condition visually. Lastly, I'll look at the M brackets and understructure and tomorrow take some pictures / videos while under way as well as underside / motor mounting pics while trailered. Will post those as soon as possible. Thanks again!!
 

airdvr1227

Lieutenant Commander
Joined
Jul 15, 2009
Messages
1,666
There should be a drain plug in the back of each log. To get the symptoms you're describing there would need to be a lot of water. You should be able to hear it sloshing around once you get it on the trailer.
 

frantically relaxing

Senior Chief Petty Officer
Joined
Nov 19, 2011
Messages
699
not sure about drain plugs on the bottom (mine are on top), but your logs may have plugs on top-- regardless of where they are, just open them. If you get a WHOOSH of air when you remove the plug, then it's airtight and therefore shouldn't have any water in it. Just put the cap back on. But if removing the plug is like removing the cap off a milk jug, it's NOT holding air which means it won't hold water either. And even if the hole is on top of the log, and is very small, water will still enter. Been there done that-- the rearmost port log had water in it when we bought it. The hole was at the very back of the log, at the end of the weld on the M bracket-- you can almost see it-- it's size, one toothpick tall x 2 toothpicks wide, at the back, almost on top, and 90 gallons of water found it's way in that hole! Took 10 years, but still... :)

loghole.JPG
 

roffey

Commander
Joined
Nov 22, 2012
Messages
2,184
if it were me I would talk to the dealer... its new and should not take on water like that. In MHO you pay the dealer for their experience and they should support their product. If I were the dealer I would want to help keep my customer happy and on the water.
 
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