Thinking about using pour foam instead of styrofoam blocks

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Mar 22, 2010
18
Macgregor 22' Olympia
When I got my 22' MacGregor it came with a number of white styrofoam blocks that were simply scattered about inside the boat. I understand they might come in handy in the event of a capsize, however, they're a bit unsightly and I'm wondering about the possibility of creating a few air cells and filling them with a two phase foam material (Aerofoam is one such product). Has anyone done this? What are your thoughts?
 

Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
Aug 22, 2011
1,113
MacGregor Venture V224 Cheeseland
Re: Thinking about using pour foam instead of styrofoam bloc

Ah - the Sumner reappears.

I don't think the foam blocks is so much about capsizes - its more about floatation to hopefully keep the boat from heading to the bottom when full of water. I'm pretty sure the boat is to be self righting even if the blocks aren't in there. Lots of self righting boats have no flotation in them from what I understand.

You can hide your floatation; If your quarters are decked over - bust up your blocks and pack them between the decking and the hull.

Put a simple divider in the space under the v-berth and pack one of them with busted up foam - the other space for storage.

Use your imagination - there are several tricks for finding places in a boat for extra flotation.
 
Sep 25, 2008
295
1970 Venture by Macgregor 21 Clayton, NC
Density

I know nothing about foam, but can you get the same and uniform density with a pour in foam.

If the density is not correct you could add a lot of weigh, and not get the same effect.
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
Re: Thinking about using pour foam instead of styrofoam bloc

dont use pour foam or spray foam in the lower portions of the boat... it is NOT a closed cell foam and WILL absorb water and defeat its purpose... it may be ok to use the stuff in a location where it has good full time drainage, but if it doesnt, in time it will become waterlogged and be a severe problem, especially if you are in an area that freezes in the winter.... the waterlogged foam will expand and can cause extreme damage to the hull...


in my boat I did use some spray foam, but very sparingly.... after rearrainging and stacking all the styrofoam blocks neatly in the hull so it would create more storage space, I used the spray foam in stratigic spots to hold them in place... i didnt use very much because i might want to remove the blocks someday, for a repair or whatever. but it freed up a lot of room.
the down side is, now that i have more gear onboard, the foam blocks may not be enough to support it all if it should swamp.... the upside is, i have more ballast, LOL.....
 
May 4, 2005
4,062
Macgregor 26d Ft Lauderdale, Fl
dont use pour foam or spray foam in the lower portions of the boat... it is NOT a closed cell foam and WILL absorb water and defeat its purpose...

1+ if water sits on it, it will be heavy and smell. closed cell foam is the way to go. HD has it in 4x8 sheets from 1-4" thick.

or try your local norther tool.. they ship trailers with Styrofoam blocks. usually free for the asking.

I did the same, used great stuff as glue/insulation more than flotation
 
Nov 23, 2011
2,023
MacGregor 26D London Ontario Canada
When I took the stock MacGreggor white foam blocks out of my boat the lower ones were waterlogged and covered with mold! I threw them out.
I like the extra storage space.
I took a look at how many other boat manufactures put foam flotation blocks in there boats. Not too many. (Why is that?)
In my opinion the foam is there for us "new" sailors. Kind of like training wheels on a kids bike. If the other boats don't have it why should I?
I've gained confidence in my ability and the boats ability. I can't knock it over. I've tried allot! So I removed the foam from the V berth and bilge areas. It keeps the bilge area cleaner too.
There still is a bit under the cockpit seat... I can't get at it easily.
 

Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
I took a look at how many other boat manufactures put foam flotation blocks in there boats. Not too many. (Why is that?)
In my opinion the foam is there for us "new" sailors. Kind of like training wheels on a kids bike. If the other boats don't have it why should I?
I've gained confidence in my ability and the boats ability. I can't knock it over. I've tried allot! So I removed the foam from the V berth and bilge areas. It keeps the bilge area cleaner too.
There still is a bit under the cockpit seat... I can't get at it easily.
I agree that not many if any other manufactures use the foam, but with our S it really isn't in the way and when you are some place like crossing Florida Bay or those that have gone over to the Bahamas or to the Dry Tortugas and you are 30-40 miles from the nearest land it is a little comforting ;). A boat can sink for other reasons than a knock-down. So if it isn't in the way why not leave it?

The Endeavour has 8 thru-hulls and most would not shut when we got the boat. One must do on her was replacing all of them and all of the hoses to them before we went back out. Not a fun or cheap job, but we knew we had to do it when we bought the boat and will feel much safer when we go out.

Sum

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walt

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Jun 1, 2007
3,546
Macgregor 26S Hobie TI Ridgway Colorado
Ive never had any reason at all to think the foam was needed.

However, you never keep any boat forever and Im not a lawyer but can imagine some remote but screwed up possibility where you sell the boat and take on some liablility for some dumb thing someone does in the future because you removed the foam. If I had removed the foam (mine is still all there), Id probably disclose that in writing to the next owner. But Im probably a little over paranoid about liability in general (and am not one to get any legal advice from).

Does the foam have any influence on full coverage insurance (also wouldnt affect me since I pretty much only get liablility, Ill self insure for the boats value).
 
Nov 23, 2011
2,023
MacGregor 26D London Ontario Canada
Re: Thinking about using pour foam instead of styrofoam bloc

I hear your concerns. I have to remember that one boat has a chunk of concrete in the ballast and the other had a hole in the bottom when I got them. (I wasn't apprised of the concrete, but did know of the hole in the other.)
When I do sell one of them it will be "AS IS".
Of course I will disclose all of the defects. Which I expect to only be those things.
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
When I took the stock MacGreggor white foam blocks out of my boat the lower ones were waterlogged and covered with mold! I threw them out.
I like the extra storage space.
I took a look at how many other boat manufactures put foam flotation blocks in there boats. Not too many. (Why is that?)
In my opinion the foam is there for us "new" sailors. Kind of like training wheels on a kids bike. If the other boats don't have it why should I?
I've gained confidence in my ability and the boats ability. I can't knock it over. I've tried allot! So I removed the foam from the V berth and bilge areas. It keeps the bilge area cleaner too.
There still is a bit under the cockpit seat... I can't get at it easily.

just a few thoughts after reading your post...
with few exceptions, styrofoam wont waterlog unless it has severely degraded, but it will mildew in damp areas.
degradation is caused by something that comes in contact with it, whether its too much sunlight, a chemical, or something that is airborne, but otherwise its a very stabile closed cell foam. but even then, the foam has to be submerged to uptake water, as it is not absorbant.
styrofoam can retain a bit of moisture in the areas of the mildew, but its only about 1/8 inch or less deep on the surface, unless it has degraded deeper into the surface.
so for whatever reason yours was waterlogged, its a very uncommon and abnormal occurance.

other boats do use foam... now. but not all of them.
Roger Macgregor was very innovative and a pioneer in several developements that many others have followed.... foam in the hull was one of them. his market was directed towards families with kids, and safety as well as simplicity was his main selling point. he produced an excellent boat for the market he was targeting.
some manufactures dont use the simplicity of the blocks, but they sometimes put the foam between the liner and hull, or some actually incorporate it into the hull alone, making it a couple inches thick, and then the liner goes in...
some manufactures dont have any floatation, and some owners are affluent enough that if their boat swamps, they no longer want it anyway.... but the best chance of survival in open water,(without a liferaft) is if you have a large piece of floating debris to hang onto while waiting for rescue. or your boat if it remains afloat.

and for several years now, positive buoyancy has been a requirement on all powerboat hulls.....

and very much like you, when I got my first boat, I put it thru things that i wouldnt ever think of doing with the boat i have now. but i learned a lot about things that have to do with sailing and boat handeling, and the whys and the hows of it all (and still learning). with the foam in place I felt confident. I took it out many times and played in the storms when no other boats wanted to be there. I tried to get it to knock down... and it wouldnt do it for me. but i had fun trying cuz i didnt know any better:D but there was one time I decided it was time to douse the sails and motor in, and as I was turning the boat into the wind, thats the moment i realized that a knockdown will come when you least expect it...its fast, its thorough, is scary, its wet, and its hard to regain control very fast when it happens so fast you cant get your wits about you....
I knocked down to starboard and scooped my cockpit full of water, and it seemed like a minute or two before the boat slowly stood back up as it rounded into the wind, and as it went thru the eye of the wind, it slammed down to port...... and for as much excitement as it all was in the moment, Im fairly certain I wont be trying to knock a boat down ever again... it taught me some respect;)
so no matter how much of a "master" you think you are to your vessel, there will come a time when it will show you a new trick you've never seen before...
my point is... you shouldnt disrespect your boat by thinking she cant to it, because she can.... and she will prove it someday when your not expecting it.

sailboats are different in some respects, but the one thing that is the same no matter what type of boat or how big it is, it doesnt make any difference if you're 300yds off shore, or 300 miles offshore, if your boat goes down, you aint gonna just walk home... and the foam blocks that are hidden below the liner and is in the way for storing more gear will always only be seen as a benefit when you need it the most.
 
May 4, 2005
4,062
Macgregor 26d Ft Lauderdale, Fl
j
and for several years now, positive buoyancy has been a requirement on all powerboat hulls.....


IIRC, powerboats under 21'

and powerboats have, no capacity limit or hp rating over 21' (or is it 25'?)
 

Yosi

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Apr 22, 2012
72
Unsure Unsure Florida
I was thinking about the same idea having used Great Stuff from Home Depot around the house. If there a way to spray it between the liner and hull I think it can add a lot of buoyancy. Still, I would not remove any foam the Roger placed there.
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
I was thinking about the same idea having used Great Stuff from Home Depot around the house. If there a way to spray it between the liner and hull I think it can add a lot of buoyancy. Still, I would not remove any foam the Roger placed there.
there are two formulations of the expanding foam.... the kind that will expand more as it cures and apply positive pressure to the joints and bulge the walls or bulkheads, and the type that is passive and will expand to fill the space but will not expand more as it cures out.....

its a bad idea to do it, but if you have you heart set on using the spray foam to fill a space inside the hull, make certain you use a large plastic bag in the hull and then shoot the foam into it and let it expand.....

if you have never used the stuff then you have no idea how it will stick itself so tightly to whatever it comes in contact with, that you cant pry or peel it loose. if you ever have a reason to remove it, you wont be able to. if you ever need to do a repair on the boat, it will be difficult to remove a section of the hull for access... its difficult to clean off of whatever it gets on, because even with harsh chemicals that will dissolve it, it doesnt really dissolve but only softens it so it can be smeared around as you try to wipe it off....

like others have said, the floatation probably isnt all that important anyway (until your taking on water), but i wouldnt remove it from my boat.
and with that said, if I had a boat that didnt have it in there, and i wanted it, I would never use the spray foam but would wait until i could get styrofoam to fill the space. which may be never, but to compromise by using spray foam is only creating a different and real problem while trying to insure against something that is extremely unlikely to happen anyway.
it doesnt make any sense to do that...:D
 
Nov 23, 2011
2,023
MacGregor 26D London Ontario Canada
I still don't have foam but if I did want it it would have to be encapsulated in plastic of some sort. Something like winter boat shrink wrap. (The soggy messy foam blocks that were in my boats would have been easily wiped off.) I had some blocks that I would guess weighed 8-10 lb. Heavy enough to not be able to hold it out by its edge flat out with one hand for too long. I have no idea how long these were submerged for. (I'm told the new boat sat on it's trailer for 8 years half in the water. Interesting water stain anyway.)
 

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Apr 24, 2006
868
Aloha 32 Toronto, Lake Ontario
There is a foam specifically designed for flotation (it is not urea like Great Stuff). Mixed with water, it creates and traps bubbles - and does not exert pressure on the structure it's poured into (as long as there is an exit hole for the excess).
A friend of mine owns one of the largest foam supply companies in Canada (our of Waterloo).
Want me to get some info on the flotation product and pricing? If its not that much volume to fill I might be able to get sample quantities.

Chris
 

Kestle

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Jun 12, 2011
702
MacGregor 25 San Pedro
I'd be curious how a water based foam would hold up in a bilge. Not being critical, but once installed it would be really hard to check.


Jeff
 
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