I just dont' get it

[LUCKYDUX]

I've read so many restoration projects but I never see anybody really stating why certain things are done, just how. I've acquired my first boat and I want to replace the decking and have some marine grade plywood lined up to do so.
My question in its simplest form is why are boats made to not let the water get down to the very bottom of the boat... as in below the decking? Seems it would drain right out once your off the water and the plug is pulled. The boat I've acquired, my first boat as you can tell, is a 17' Lundau Superhawk if that helps with any answers.

 

[Tail_Gunner]

Re: I just dont' get it

In a nut shell..Boats are still hand built...in masses. They dont pay boat builders like high priced craftsman..Jaded response but true. Well you could price a 22' Colbalt and then say your average 22' boat...Not going to mention some old names...

 

[LUCKYDUX]

Re: I just dont' get it

You lost me captain???

 

[oops!]

Re: I just dont' get it

whats up dux ?...

WELCOME TO IBOATS

in the old days of boat building.....the water could drain.

however....in the early 70's a law came in that every boat under 24 feet had to have flotation foam.

this caused great panic by the builders because the water would no longer be able to drain.....they tryed everything....big chunks of foam. so the water could get around the foam and to the bilge.

by the late 70's the builders realized that the foam could be structural, its anti crush strength is fantastic. it was good sound proofing, and best of all, if the foam did get waterlogged it would rot the wood and the boat would be toast. thus giving the boat a 20 year life expextancy under average conditions and use. thus the boat no longer had an indefinite life span.

this was a gold mine for the builders....they could use less materials (fiberglass and resin) because of the anti crush and use more foam for structural purposes.

when we rebuild boats here at i boats....we build them with the idea that water WILL get in there and build accordingly for proper drainage.
some builders here even forgo the watersuckingfoam and build with out it...choosing to take their chances in case of swamp or sink.

the best way to approach your build...is to use the idea that water is SUPPOSED to be in there...and channel it so it will drain properly, and give it plenty of vents for the air to get around in the hull under the deck.

hope that answered your question.

cheers
oops

 

[zarillus]

Re: I just dont' get it

Having enough water underneath the deck would potentially swamp the boat and you could end up in a real emergency.You have to have some kind of positive flotation so the boat floats.A good example of this would be to put an empty two liter bottle in a bathtub and just watch how well it floats.

Now fill the two liter half way full with water and you will see that it sits lower in the water.Then fill the two liter to the top and it sinks too the bottow.It no longer has any positive flotation so it sinks just like a boat that was full of water.

Most of the guys on here are interested in fixing there boats and the science is really not mentioned if at all.

Take it easy

 

[LUCKYDUX]

Re: I just dont' get it

Wow, thanks guys!! I'm quite beside myself right now with this new info So it seems that if a person trusted their bilge and possibly backup bilge, (for the safety first people) then said person could have more storage/panels and such...the possibilities are looking wide open!
Now I'm wondering if a boat without the foam would act any different on the water, say when you turn the wheel all the way? Would anyone happen to know if it would react differently? I don't quite know why but it seems that it may.

Thank you for the warm welcome guys, I frequent a few forums non related to boating and came prepared for battle...I imagine I look a tad silly now with my armor on sitting in the den ...seems about as useless as foam in a boat about now

 

[drewpster]

Re: I just dont' get it

I think the best and perhaps safest way is to rebuild them just like the factory did it. Of course you can make improvements to the original design, but factory is the way to go on my opinion. Foam is a major issue in here. Many resto boats have foam under their decks. It may be true that a boat with the correct amount of foam will stay afloat in an emergency. It may also be true that a boat with foam will sink like a stone. One thing is for sure, it wont float very well is the foam is soaked with water. However, if my boat had foam under the deck, I would most likely replace it. Then I would take extra care that it would not soak water again.

 

[Bondo]

Re: I just dont' get it

Now I'm wondering if a boat without the foam would act any different on the water, say when you turn the wheel all the way?

Ayuh,... The foam is nothing but added weight, until the hull is swamped...

 

[Kiwifisher]

Re: I just dont' get it

Now I'm wondering if a boat without the foam would act any different on the water, say when you turn the wheel all the way? Would anyone happen to know if it would react differently? I don't quite know why but it seems that it may.

No sirree, boat will handle the same. There is a popular misconception that foam in a boat makes it float better. I used to also think that! However, foam only has any use when a boat becomes swamped/filled with water. The foam then takes up the space that water would have. As the foam is lighter than water, the boat won't sink, just sort of lie semi submerged. If you did not have the foam and the whole boat fills with water, down she goes.

Some folks leave the foam out the bottom but pack quit a bit under the gunwhales to aid in keeping her afloat.

 

[LUCKYDUX]

Re: I just dont' get it

Seeing how I have only taken it out once with family and the misses packed up WAY more than needed and I barely had room for my fishing equipment, I'm gonna go with no foam and more compartments. To ease my mind though I ordered 2 RM100 Rule bilge pumps...my next question is would it be beneficial to put one around the middle of the boat somewhere or just have them both in the back and use one as a backup? Thanks guys this forum rocks!

 

[westexasrepublic]

Re: I just dont' get it

IM NOT SURE WHY YOU WOULD LOOSE STORAGE, CAN YOU POST A PIC OF YOUR BOAT....ALSO SO YOU KNOW, NOT HAVE FOAM WILL CAUSE MORE FLEX, VIBRATION AND STRESS ON THE HULL. AS MUCH AS WET FOAM SUCKS, IT IS BETTER THAN AN OVERSTRESSED CRACKED HULL. HERE ARE PICS OF MY REBUILD, THAT I ASSURE HAS NOT COMPROMISED ANY OF MY STORAGE AND WILL BE MUCH STRONGER WITH FOAM FILLED IN ....

THE MIDDLE CAVITY WILL BE FILLED ALONG WITH OTHER AREAS TO DAMPEN THE POUNDING OF WAVES AND STRESS OF HARD TURNS. TO ME ITS A NO BRAINER.

 

[109jb]

Re: I just dont' get it

Seeing how I have only taken it out once with family and the misses packed up WAY more than needed and I barely had room for my fishing equipment, I'm gonna go with no foam and more compartments. To ease my mind though I ordered 2 RM100 Rule bilge pumps...my next question is would it be beneficial to put one around the middle of the boat somewhere or just have them both in the back and use one as a backup? Thanks guys this forum rocks!

First of all, the biggest bilge pumps around for small boats are not going to keep up if the boat swamps. Take a roller the wrong way and stuff the bow and its all over but the crying.

You might want to check out the links below before making your decision.

http://forums.iboats.com/showthread.php?t=426421

http://www.ohiogamefishing.com/community/showthread.php?p=1060828

It is easy to say "It will never happen to me" until it does. When I re-decked my Sea Ray I would have loved to eliminate the foam for weight, drainage, and storage reasons. I put it back in because I love my family. Even if I only used the boat by myself the foam would have gone back in because coming back wet is better than not coming back at all. In the articles above, what chance of surviving would those men have had if their boat went to the bottom?

If as you say your wife is bringing "WAY" more stuff than needed then you need to talk to her about not bringing so much.

BTW, are you telling your wife that you are preparing to eliminate a safety feature of your boat? Does she have a say in it?

Below is an example of what flotation foam can do for you. Without it the boat goes to the bottom. This is not typical as most won't stay this far out of the water, but it shows what the foam can do.

http://walleye.outdoorsfirst.com/watch.asp?id=2087

 

[Kiwifisher]

Re: I just dont' get it

Before we get too carried away in our scaremongering, we need to take a number of factors into account.

For a start, virtually all material used in boatbuilding is less dense than water and will therefor float, thereby reducing the amount of additional flotation required to stop a boat from sinking.

Various means of providing additional flotation have been in existance for decades. Expanding foam is just one of those, being the cheapest and easiest for boat builders to use.

If foam is eliminated from below deck and the deck fitted and sealed off properly, an airtight compartment is created which provides adequate floatation to keep the boat afloat. The only drawback with this system is when the boat strikes a log or a rock and the hull integrity is damaged allowing water ingress. This can be overcome by dividing the under deck area into separate sealed compartments, much like the tubes on an inflatable.

A boat using seperate watertight compartments with bilge pump and drainplugs fitted, would be far safer than a boat using foam that has become waterlogged.

The safest would obviously be to use closed cell foam such as pool noodles, This does not absorb water and can be placed in such a manner as to ensure good drainage to the bilge.

There is no absolute right way to do this.

 

[westexasrepublic]

Re: I just dont' get it

http://walleye.outdoorsfirst.com/watch.asp?id=2087

<PREVIOUSLY POSTED LINK REALLY SAYS IT ALL, IT'S NOT EVEN REALLY A CONVERSATION

 

[JAFO1]

Re: I just dont' get it

Before we get too carried away in our scaremongering, we need to take a number of factors into account.

For a start, virtually all material used in boatbuilding is less dense than water and will therefor float, thereby reducing the amount of additional flotation required to stop a boat from sinking.

Various means of providing additional flotation have been in existance for decades. Expanding foam is just one of those, being the cheapest and easiest for boat builders to use.

If foam is eliminated from below deck and the deck fitted and sealed off properly, an airtight compartment is created which provides adequate floatation to keep the boat afloat. The only drawback with this system is when the boat strikes a log or a rock and the hull integrity is damaged allowing water ingress. This can be overcome by dividing the under deck area into separate sealed compartments, much like the tubes on an inflatable.

A boat using seperate watertight compartments with bilge pump and drainplugs fitted, would be far safer than a boat using foam that has become waterlogged.

The safest would obviously be to use closed cell foam such as pool noodles, This does not absorb water and can be placed in such a manner as to ensure good drainage to the bilge.

There is no absolute right way to do this.

HOWDY!

I don't think anyone is running a 'scaremonger campaign.' We just point things out and share our observations. Some more enthusiastically than others. The beautiful thing about your boat, is that it is your boat. You can do with it what ever you want.

I opted to go back with pour in foam (which is 98% density), like came from the factory. Yes, the old foam was soaked in places. But this was due, mostly, to poor maintenance. I desperately tried to justify using pool noodles or pink foam board. The reason I chose to go back with pour in, is because it isn't that much more money than the pink foam boards, and it provides much more (my opinion) rigidity. Hopefully preventing 'oil canning' of the hull.
Take your foam out and make it all storage under the deck. But remember, those compartments must be water tight to act as flotation. You must have a sealed lid and perfect glass craftsmanship.

There is also the issue of USCG rules, which I don't know what they are off hand. But I think foam is required in small boats. Check the 'sticky' at the top of this section, I think it talks about USCG regs.

 

[109jb]

Re: I just dont' get it

Before we get too carried away in our scaremongering, we need to take a number of factors into account.

For a start, virtually all material used in boatbuilding is less dense than water and will therefor float, thereby reducing the amount of additional flotation required to stop a boat from sinking.

Really> So the fiberglass that my boat is made of is less dense than water? Or the aluminum of a tinny? The density of fiberglass is about 1.5 grams per cubic centimeter, aluminum is about 2.7 grams per centimeter cubed ans water is 1.0 grams per centimeter cubed. What does this mean?? Fiberglass and aluminum sink. Unless you have a wood boat, most of the materials will not float.

Various means of providing additional flotation have been in existance for decades. Expanding foam is just one of those, being the cheapest and easiest for boat builders to use.

If foam is eliminated from below deck and the deck fitted and sealed off properly, an airtight compartment is created which provides adequate floatation to keep the boat afloat. The only drawback with this system is when the boat strikes a log or a rock and the hull integrity is damaged allowing water ingress. This can be overcome by dividing the under deck area into separate sealed compartments, much like the tubes on an inflatable.

Making the compartments truly air or watertight is a lot more involved than just saying it. If the compartment is breached then it does nothing to help. If the under deck area is filled with foam an the hull is breached then the foam actually prevents the ingress of water.

A boat using seperate watertight compartments with bilge pump and drainplugs fitted, would be far safer than a boat using foam that has become waterlogged.

What about foam that isn't waterlogged? In my opinion, waterlogged foam comes from neglect. I personally would take the foam filled boat over the one you describe as long as the foam isn't waterlogged.

The safest would obviously be to use closed cell foam such as pool noodles, This does not absorb water and can be placed in such a manner as to ensure good drainage to the bilge.

There is no absolute right way to do this.

You must also consider that some boats actually use the foam as a structural element.

 

[LUCKYDUX]

Re: I just dont' get it

Dang, where did all my support go I thought things were looking up for a day and now it seems everyone's opposed...thanks everyone for the input and links, I guess I need to reread and rethink my options. Sorry for starting a new thread that obviously has been started many times, I just never found them.
I'm not the smartest man in the boat so I'm thinking about constructing a small scale experiment so I can put it into better perspective for myself. I understand some people dwell on things that others would not (such as safety), myself though, I kind of wing it and hope for the best. I have no attachment to this boat or anything that will be on board besides my friends and family, and being someone already invented pdf's, that takes care of that. Last question for now...can everyone at least agree that the pour in foam provides enough support to make it worth doing?

Hey westexrep, do you own a frontier?

 

[Kiwifisher]

Re: I just dont' get it

Really> So the fiberglass that my boat is made of is less dense than water?

Modern boats are all glassed over a core, usually foam thus making it lighter. Add all the wood such as stringers, transom etc, you would be fairly close to neutral bouyancy. That is why it does not take heaps of additional flotation to keep a boat afloat.

Making the compartments truly air or watertight is a lot more involved than just saying it. If the compartment is breached then it does nothing to help. If the under deck area is filled with foam an the hull is breached then the foam actually prevents the ingress of water.

That's what I said. Making compartments watertight is a mission but is not impossible.

What about foam that isn't waterlogged? In my opinion, waterlogged foam comes from neglect. I personally would take the foam filled boat over the one you describe as long as the foam isn't waterlogged.

I think everybody, including myself would agree with you. The key however is when the foam is not waterlogged. Not many people know when there foam is waterlogged however.

You must also consider that some boats actually use the foam as a structural element.

That's correct. That's why some owners add stringers and extra mat to reinforce the hull. Just to set the record straight, I'm not advocating widespread removal of foam at all. I am trying to point out to the OP that there are different ways to do things, and what the factory used originally is not always the best option. Also the USCG regs only require flotation and does not ask for foam.

 

[45Auto]

Re: I just dont' get it

US flotation laws only apply to boats UNDER 20'. You don't have your location shown, so if you're in another country, find your own laws!

They start here at 33 CFR 183.101:

http://law.justia.com/us/cfr/title33/33-2.0.1.8.44.html#33:2.0.1.8.44.5

Stick a 3' swim platform on the back of your boat then come back and post that it's 20' long. Then it'll be just like all the other MILLIONS of boats 20' and over WITHOUT foam, and everyone should be happy. Or just tell them it's a submersible, and the foam rules don't apply. Just make sure the foam wasn't structural.

None of my boats (all over 20') have any foam in them and it doesn't bother me a bit.

 

[jfried]

Re: I just dont' get it

Sort of a newbie question here...please don't flame me if I'm way off base.....in relation ot the weight aspect.

Obviously foam weighs more than air, and as a result would be the same as having more people on board -- draft a little deeper and require a little bit more power (and more gas). It also would provide less floatation per cubic foot than a completely sealed compartment of air.

However, would it not also provide the benefit of greatly enhancing the stability of the boat by keeping the centre of gravity as low as possible? A boat that has lots of weight below (or very near) the water line would be less susceptible to the effects of potentially misbalancing the weight associated with passengers/gear, as well as taking waves anything but head-on. I believe in theory, you would reduce the pitch/roll associated with everyday boating.

For your average boater (and that certainly isn't this group), I would think that it would be desirable to have more stability versus a boat that is as light as possible (obviously not the case if you're trying to set world speed records).

Also, if you used expanding foam versus pool noodles/pink stuff, would it not significantly reduce the stress on both the fiberglass hull, and your brand new floor; as the impact of water on the hull would be distributed over the entire floor and the impact of people/gear on the floor would be distributed over the entire hull as opposed to just the spots that are attached to the stringers.

I would think that if you could drain it properly (no idea how you would do this), you would increase the longevity of your restoration work, as the weight of that 300lb passenger steeping between two stringers is braced slightly better, and the impact of that landing after getting some air is distributed over more surface area.