2000 Crest DL Pontoon Hissing Noise from Pontoon

CDBettler

Recruit
Joined
Jun 22, 2017
Messages
3
First post here, looking forward to gaining some great knowledge here!

Just picked up this pontoon, needs some cosmetic work yet but I did have it out on the lake for a 2-3 hour test spin last week. I didn't see any bubbles coming from the pontoons, and i didn't hear any sloshing, but it makes me nervous because I always hear a hissing in the evening from the left pontoon, rear section. I sprayed some soapy water around, didn't see any bubbles and the noise will just disappear as time passes. Is this a leak? Is this natural pressure release? Also - no plugs on the bottom on the pontoons, just on the top.

I'm heading to Lake Otisco for 4th of July, boat runs fine just worried that I'll come out in the morning and half of my boat will be in the water...

Any tips, tricks, or reassurance that I won't have a sunken ship in a week would be great!
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,310
most likely its either a leak at one of the m-brackets or its pressure pushing out of the area where the plugs are as the temperature rises and falls during the day.

if you want to check for leaks, pressurize the logs to about 2psi and use soapy water.
 

CDBettler

Recruit
Joined
Jun 22, 2017
Messages
3
most likely its either a leak at one of the m-brackets or its pressure pushing out of the area where the plugs are as the temperature rises and falls during the day.

if you want to check for leaks, pressurize the logs to about 2psi and use soapy water.

Ok that's what I was thinking - I'm just a tad worried about it because I've never done this type of thing. Heard horror stories about pontoons popping, I don't want that to happen!

Technically I believe my toons are chambered - so if i did have a leak the boat wouldn't totally sink on me, right?


Thanks for the reply, much appreciated!
 

HotTommy

Lieutenant Junior Grade
Joined
Mar 15, 2013
Messages
1,025
CDBettler,
What follows are general observations and do not refer to your specific boat because I am not familiar with your boat. But perhaps it will help you rest easier and better understand how to evaluate your boat.

First, I believe most if not all pontoon boat logs are vented to allow for expansion and contraction of the air within. The vents are usually on the top and are shielded to prevent random water spray from entering the log through the vent. On my boat it is a small tube shaped like an inverted U with the opening pointing down.

If you have a leak below the water line of a log you will not likely see bubbles. The water will force its way into the log and push the displaced air out through the vent.

If you have a chambered log, each chamber would have to be sealed with its own vent to prevent water from making its way from one chamber to another. Some logs have partial chambers for structural strength that may also keep any water inside from sloshing freely from end to end, but they will fill if there is a substantial leak. Some logs also have styrofoam like filling to limit the amount of water than can intrude in case of a leak. That foam has been known to become water saturated and very heavy.

If you had the boat in the water for 2-3 hours and it did not list noticeably to one side, it does not likely have a significant leak. I worry every spring when I put my boat in the water for the first overnight stay. I'm always relieved when it is still floating the next day.

If your boat does not have drain plugs in the logs, it is possible to add them and know for certain if there is water within. Use the search function here to read about drain plug ideas.

Lastly, if you can locate the vents on your logs, use a length of old garden hose to listen when you next hear the hissing. Hold one end to your ear and the other by the vent. If that is the source of the hissing you will hear it.
 

jhohman35

Cadet
Joined
Jun 24, 2017
Messages
9
I found my leak by what was said above. I used my air chuck and put a rag around it to fill up the hole. 2 pounds of pressure is plenty and then I took a old windex spray bottle with soapy water and went around all the welded areas. I went to the hardware and found a 2 piece marine grade JB weld. They had putty and then the stuff in the tubes. Both worked fine and when mixed it turned a gray color so its isn't really noticeable. Good Luck!
 

CDBettler

Recruit
Joined
Jun 22, 2017
Messages
3
Thanks everyone for the replies! Tomorrow I'm going to put a little pressure in the toons and see what comes of it. I'm assuming it is near an M bracket but we shall see. I'll have to also check for vents - I haven't been able to spot them yet but I'll check again.

All the advice is much appreciated!
 
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