Monark hull question

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Monark hull question


Post by Dsinclair74 »

I have a quick question about an old 18 tri hull monark I’m restoring .
between the floor and hull there was about 1/2 -1ft of water soak foam that I pulled out .
i understand that the foam was there to prevent the boat from sinking if ever it filled with water .
but other than that does it serve any other function?
like structural or otherwise?
i would rather not put new foam back in but don’t have any experience with aluminum hulls
the hull has aluminum stringers and bracing through out so I don’t see the foam adding to strength but I’m by no means a boat builder

Thank you for any help/ knowledge
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Re: Monark hull question


Post by kmorin »

Dsinclair74, welcome, if this is your first post, don't see any details to the right of your name in the header so.... I'm assuming you've just dropped by... once I closed the reply your info showed up!

first, Monarch was or is a major aluminum boat manufacturer- and that implies they have to comply with all marine regulations - you may not have too.

The foam was, as you've mentioned installed to meet the compliance with the regs at the time it was built. But as you have also noted, and my learn more with further inspection- foam is not the ideal flotation material.

I don't think any manufacturer would rely on foam for a structural element below decks? I'd say there was plenty of structure in the metal to hold up to use, and keep the boat in shape. So replacing it, especially with poured or sprayed in foam is not the best idea in your restoration.

Cleaning further- there could be some hull panel corrosion sites due to the foam holding water against the metal- I've posted on this topic in many places here- so the archives and search will help you review what others have discussed about this type of problem.

Hope this helps a little, it is a wide ranging subject and one that covers different boats' circumstances so a read though our site archives will reward your efforts, IMO.

Kevin Morin
Kenai, AK

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Re: Monark hull question


Post by welder »

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