Foam!

[cpasseno03]

Allright... Heres my situation. I have a 1957 Lone Star 23 foot aluminum bathtub. The bow gets pretty vocal about waves, big ones make it oil-can quite a bit. I have been adding angle tin peices here and there and have stopped the serious oil-cannings. I cannot help but wonder about pouring a bucket of foam in there though. That would be stiff enough to really slidify the bow right? Is the stuff waterproof? I am already a little bowheavy with the inboard engine, so how much does it weigh? And of course the biggest question, where can I get it and HOW MUCH will I expect to pay this time around? Thanks in advance!Craig
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Herbalaire

 

[snapperbait]

Re: Foam!

If ya filled the area, i believe that'd stop the oil canning..<br /><br />It's waterproof to a point.. If you could leave room for drainage around the foam, the likelyhood of it absorbing water is very low...<br /><br />For a two gallon kit @ 2lbs density.. weight is 16 LBs, Kit yields approximately 8 Cubic Feet, cost $48.00 <br /><br /> http://www.shopmaninc.com/foam.html

 

[Winger Ed.]

Re: Foam!

Flexing and 'oil canning' isn't automatically bad.<br /><br />Ask yourself:<br /><br />If I jump off the roof of the house, my knees will flex when I land, won't they"?<br /><br /><br />So, why is the front end of your 'fine old lady' moving a bit under the stress of a few high waves in the water, automatically bad? <br /><br />She pushes, and curles most of the waves away; rather then them landing full force in your face or ending up on the deck/floor don't she? <br /><br />If it was me,<br />And the rivets didn't leak,,,,, I'd press on while holding the throttle all the way down against it's stop no matter how much water is above, and ahead of ya.<br /><br /><br />think about it-----<br /><br />She's brought everybody home OK all these years without adding all that new fangled Sh##, plus its aditional weight and reduciton in speed/fuel economy while on flat water,,,,<br /><br /><br />no reason she won't next week too, just like she could do when she left the factory back in '57 ,,,,,,,, <br /><br /><br />Let us not forget,,,<br />That before most folks here were born, or were parked in front of the TV by thier baby sitter,<br />while wearing a 'heavy' diaper, and thus sitting in thier own,,, 'poop' shall we say..<br /><br />Your boat was ready and willing to put in a hard day's work.........which it did, and brought everybody home safe.<br /><br />If you've done your homework, and maintained her, I can't see any reason why she won't do that for another generation.

 

[Eggkr8]

Re: Foam!

I see your point and understand the physics of what you are saying. But I got to disagree with you on one point. Aluminums ability to hold up to repeated stresses and strains without cracking isn't really the best. I have seen bicycle frames designed to use flex as part of their suspension, but they were titanium, I've never seen springs made from aluminum. <br /><br />My point is , if aluminum keeps flexing (or oil canning)it will crack. I bet we all have torn a soda (or beer) can in half by stepping on the middle and flexing it until it tears<br /><br />Second point is, what would this motion be protecting? I admit to being pretty much a newbie, but isn't everything in the boat designed to take a whack once in a while?

 

[cpasseno03]

Re: Foam!

Thanks for the info!Winger, By all means I know what you are saying. I have a friend with a similar boat and his single oil can scared the **** out of him! He actually thinks he is goign to re skin it with 1/8 or 3/16" aluminum!!! Now that is crazy, but he cannot be talked out of it.As for mine, you speak of it bringing everyone home safe, well it brought them home but not safely! Before me, it was owned by indian fishermen, who admittedly pounded it through 6-8 foot waves with several tons of fish aboard, with TWO 75 horse outboards on a ROTTEN transom without any plywood sdecking or gunwales. I put in 400 1/4" galvanized carriage bolts. The ribs were all cracked, the rivets were all loose, many had fallen out of their holes. I found the boat in the junkyard and it would hardly float on the red clay and car rims underneath! So, In the rear section, I put two 4x6 stringers to mount my inboard engine, I bolted them to every rib, replaced the broken ribs under the engine with angle iron. Then in the front section I tied the 4x6s into 2x8s which go up to the big wide rib/bulkhead in the bow, which I backed with half inch plywood, along with the one in front of that. I know a little oil canning is ok, but the one spot I seem to have left vulnerable was the bow ( so did Lone Star) It is pretty violent, and I would like to help it out. You mentioned milage too, I get 5 miles per gallon at 20 miles per hour with my little 162ci graymarine 4 cylinder.Thanks again!Craig
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Mazda Rotary Pickup History

 

[cpasseno03]

Re: Foam!

Well I took her out today in some 4-6 footers, and gave her a beating she'll remember!! After bolting in some light angle iron in the bow and a few cross braces from outer rib to outer rib, it did pretty good. I only got one oil-can. I wound up between two freighters passing. 15 mph through those mountainous peaks was about all she wanted to do, what a ride! I cant forsee and popping rivets or cracking ribs anymore like when I found it. I think I have the whole ting braced up strong enough. Dont know if I still want the foam or not.Thanks for the help though, I couldnt figure out where to get it!Craig
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Honda Cn250

 

[Winger Ed.]

Re: Foam!

Second point is, what would this motion be protecting? <br /><br /><br />With a little flexing, you can often avoid something cracking. A little flexing can spread the tension or forces around better rather than letting them concentrate in one spot. <br /><br />Like a airplane wing for example. If it was strong enough not to flex, it would be incredibly heavy and perhaps brittle.<br />So, they're made to be able to flex a bit. I've been on airliners where the wings looked like they were flapping, they flexed so much... and that is normal for them.<br /><br />As a kid, I never knew how much a pickup truck frame flexes and bows back & forth until I was riding in one and stuck my hand between the bed & the cab.<br /><br /><br />Certainly everything has its limits, but just because something moves under stress isn't automatically bad.

 

[cpasseno03]

Re: Foam!

Winger... I know what you are saying. The bow still moves a little, but trust me, I know I have avoided cracks in that area. It used to bounce in and out over one smal certain area which clearly needed reinforcement. It moved in and out 2 or 3 inches on a FLAT day. The flexing stopped at the nearest rib, almost like a hinge. Now you must admit aluminum is not good for that! I had to lengthen my trailer 6 feet to fit the boat, now the trailer flexes like mad! I dont plan on doing anything though because its made of steel, and comes nowhere near the bending moment. Oh, and I have a model A book that you would like, it shows the frame twisting so much that the front and rear axles were perpendicular!Craig
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Suzuki x-90 history

 

[cpasseno03]

Re: Foam!

oh heck, I'll talk about airplanes too while I'm here. (On smaller ones) Airplanes are a work of art! They are EXTREMELY light, and EXTREMELY strong and rigid in the right direction. One part of one rib on a wing willnot hold but a few ounces, yet the whole wing can withstand something like 15 thousand pounds. I once picked up the frame of a fuselage my uncle was building. My dad picked up the other end, we tried to twist it for all we were worth and it did not budge any conceivable amount. Theres a difference between flexing in a pickup or trailer, and an airplane or aluminum boat.Craig
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