18 foot Manatee

[arcadiainc]

The floor was a little spongy so I took a saw to her. Turns out the floor was not attached to the stingers. A previous restorer had not screwed it down. The stringers are in good condition. I just need to add a little cloth and epoxy and they are good to go. However the remaining foam is water soaked. My thought are to dig it out and do without. What is considered best practice? Replace the foam with an approved product or leave it open to air dry? Any and all information will be appreciated.

 

[Woodonglass]

Re: 18 foot Manatee

What have you done to ensure the stringers and transom are "Good to Go!" ??? IF the foam has been waterlogged for any length of time, there's a very good chance the stringers and transom have been compromised.

 

[arcadiainc]

Re: 18 foot Manatee

The foam is on the outer edges of the flooring away from the stringers. The stringers are solid with no signs of rot. No foam was left in the center parts of the boat. At one point not long ago the stringers were fiber glassed over. This covering is cracked in places. Presently the stringers and flooring are open to dry. My tentative plan is to repair the fiber glass as necessary, give everything a couple coats of epoxy and paint. Next to install a new floor with out foam so air could circulate. Is this a valid idea or should I fill everything with approved foam. Thanks

 

[Woodonglass]

Re: 18 foot Manatee

Again, what have you done to ensure the stringers and Transom are solid and sound. A visual inspection or tapping on them with a hammer, is NOT adequate. If you have not taken "Core" samples of the wood and looked at the shavings then you have no way to know for sure they are good. Not busting your chops, just making sure you KNOW they are good before you cover them back up with a new deck.

 

[Arawak]

Re: 18 foot Manatee

I'd take a drill with a small bit and drill into the stringers here and there and see what you get. You'll be really lucky to have sound wood under cracked fiberglass. If you luck out, fill the holes with some dollar store two part epoxy. If not... well... rip her out and start from scratch.

Honestly it sounds like the last guy slapped some stuff together over what was already there. If the fiberglass is cracked then that should send some warning bells.

 

[jigngrub]

Re: 18 foot Manatee

Post some pics so we can see what you have to work with, and so we can help you better,

 

[CobyAhh]

Re: 18 foot Manatee

The foam is on the outer edges of the flooring away from the stringers. The stringers are solid with no signs of rot. No foam was left in the center parts of the boat. At one point not long ago the stringers were fiber glassed over. This covering is cracked in places. Presently the stringers and flooring are open to dry. My tentative plan is to repair the fiber glass as necessary, give everything a couple coats of epoxy and paint. Next to install a new floor with out foam so air could circulate. Is this a valid idea or should I fill everything with approved foam. Thanks

I would consider using rigid foam board as flotation. It doesn't absorb moisture, its easy to cut and stack, it allows air and water to flow around it. You can get 4'x8' sheets up to 2" thick. Also much cheaper than pour foam.

 

[bakerjw]

Re: 18 foot Manatee

I just checked on foam prices last week. a 4'x8' 2" thick sheet costs around $40 tax included. That is 5.3 cubic feet. An 8 cubic foot package of 2 pound foam is $67.00 from US Composites. Sheet foam is a bit cheaper and IMHO a decent way to extend foam, but expanding foam also adds a level of structural rigidity to compartments where it is used. If things are sealed up right, then water should never get to the foam to begin with.

The OP is well off to go and drill core samples in the stringers. My current rebuild was touted as being fine by a local boat repair shop. Solid as a rock. Ended up being water saturated to the gills. Hence my rebuild.

 

[jigngrub]

Re: 18 foot Manatee

Sheet foam is a bit cheaper and IMHO a decent way to extend foam, but expanding foam also adds a level of structural rigidity to compartments where it is used. If things are sealed up right, then water should never get to the foam to begin with.

The OP is well off to go and drill core samples in the stringers. My current rebuild was touted as being fine by a local boat repair shop. Solid as a rock. Ended up being water saturated to the gills. Hence my rebuild.

That' right!

Expanding foam also bonds/fastens itself to the hull and will actually seal the hull and keep water out of the boat should the hull become breached /gashed and sheet foam will not do this.

Also, sheet foam needs to be fastened to the inside of the boat to prevent movement in any direction per USCG recommendations:

Flotation Material Installation Requirements

a) Air Chambers


Air chambers shall maintain their integrity under pre-test conditioning and under flotation test conditions. They shall not leak when subjected to an internal air pressure test and shall not allow the ingress of water when submerged to at least a depth equal to that required in the flotation test.

b) Plastic Foam Blocks and Other Shapes


1) A method of identifying foam blocks and other shapes must be employed to assure that each boat gets the correct amount of flotation in the correct location.

2) Expanded polystyrene foam must not come in contact with uncured polyester resin or fumes.

3) Foam blocks and other shapes must be secured so that no movement in any direction occurs that will effect the flotation's performance.

4) Installation must be in a manner that will prevent:
?damage from occupant contact
?deterioration from exposure to direct sunlight
?damage from normal use of the boat.

5) The space provided for the installation of foam blocks must be large enough to prevent the necessity of using force that will deform the shape of the block during the installation process. Deformation will lower the volume, and therefore the total buoyancy, of the foam block.

That is from here:
Flotation - Flotation Materials

This is something the majority of people on this site don't realize and they don't do when installing the sheet foam in their boat, they always lay or stack the sheet foam loose below deck.

 

[kjdunne]

Re: 18 foot Manatee

Arcadiainc, pics please! I have a 18 ft. Manatee cuddy and would love to see the stringer layout and and how they were built. I've had very little luck finding info on them. They seem to be a well built boat and were, still are, popular here in the Northeast. Most of the ones I see now have been converted into fishing rigs after their original family pleasure career. Thanks.

 

[mbasura]

Re: 18 foot Manatee

Best practice is not to screw the deck to the stringers. Best to thicken a two part epoxy like West System or equivalent and use that like glue. It will hold the deck to the stringers better than any fastening. The screws themselves are likely to become paths for water to penetrate into the spaces between between the stringers, and with no way out will rot the boat again. You can trust the epoxy alone. I rebuilt my boat 4 years ago without a metal fastenings at all at it is still going strong.

 

[Woodonglass]

Re: 18 foot Manatee

It should be noted, that the USCG requirements quoted previously on this thread are for Boat MFGs only and do not apply to Backyard Boat Restoration projects. It is highly recommended that flotation foam be used when and where possible but strict adherance to these regulations is not required.