Old MonArk 1970 17 ft pontoon boat

Mapquest68

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Don't know who to ask or what to ask... So here goes. I am re-decking/ rebuilding my old 1970 Monark 17 ft pontoon boat. When I pulled the carpet off the end of the toon I found a round "hatch"that is screwed down with about 8-10 screws. I have no idea what it's for unless it's to get water out as there are no drain cocks on the end. At the front of the toons there is a Schrader valve and just aft of it is a bolt sticking up with a washer and a rubber seal on the underside. The bolts I'm sure are probably not removable as every bolt and screw I've dealt with on this thing has been ground off with a cut off wheel. The toons are flat on top. They are not round. More of a U shape{?}. I can't find any info at all on this old boat online and hope maybe someone in here helped their Grandpa rebuild theirs back when they were kids! I can post some pics later if I get any responses. Thanks!
 

ahicks

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Is there a question in there?

I would keep the hatch functional for sure. They may come in handy one day.
 

Mapquest68

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I'm guessing the round hatch is a inspection plate. I don't know what the bolt on the front of the toons are for. That is what I'm asking about. The gaskets are sun dried and cracked. I'm about ready to put this thing in the water and I want to be safe and I worry about taking on water,. The drain plugs have been welded over years ago and I have no way of draining the logs if they take on water. Perhaps that's what the round hatches are for... It has been suggested that the bolts at the front are pressure relief. (?) I haven't Click image for larger version  Name:	20200924_162301.jpg Views:	1 Size:	219.1 KB ID:	10935081 found anyone that knows. I just don't want to be a submarine commander first time I launch! I have a buddy that said not to worry as they're on top and shouldn't get any thing more than just splashes because it's on top. I'm just a nervous Nate and want to be sure. Thanks for any help or advice you guys can give!
 
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Mapquest68

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Here is a picture of the round inspection plate. Approximately 6 inches or so. Am I right in believing this is just an inspection port?
 

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HotTommy

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IMHO, it doesn't matter what those were intended for as long as they don't leak. From the pictures it looks like you'd have to cut them off and replace them if you ever wanted to use them. If it were mine, I'd clean them up so a healthy dose of marine sealant would stick. The only other thing I'd want is a way to equalize the air pressure inside the logs, and I believe you said there is a valve that can serve that purpose.
 

ahicks

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I'd be curious about what was underneath that plate. Would have to open it up for a peek. If inconsequential, put it back!
 

HotTommy

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I'd be curious about what was underneath that plate. Would have to open it up for a peek. If inconsequential, put it back!

My guess would be a crossbar with that bolt welded to it. That and the rubber gasket allowed the hole to be sealed up. There's a risk of dropping stuff into the log if that bolt is cut.
 

Mapquest68

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My guess would be a crossbar with that bolt welded to it. That and the rubber gasket allowed the hole to be sealed up. There's a risk of dropping stuff into the log if that bolt is cut.

I had the service manager at Pontoon Stuff look at the same pics. He believes it to be a pressure release of some sort. I guess that's the problem with really old stuff: The people that built it have long been retired or no longer reside on this side of the dirt! As far as safety goes... Should I be worried about this or just put some silicone around the gaskets and let 'er rip?It is above the water line and unless I am on a really rough patch of water I don't think I would be taking water over the bow. The guy also suggested putting air in the toons with the Schrader valve then checking for leak down. I'm thinking to air it up (not too much) I have read all other this site about the dangers of over inflating the toons. Do any of you know where I can get a pressure gauge that reads 2-4 psi? Will a regular tire pressure gauge (digital) suffice? As always- Thanks in advance for any and all advice and suggestions. Regards, Mapquest68
 

matt167

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I use run of the mill Accutire digital gauges at work. They will register down to 1 PSI. I think they cost $11
 
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