Questions for owners of FC-470 with Aluminium Floors

[F470]

Wow. Super helpful. I'm in the very same seat as you were. Feels like it is excessively long and that it could benefit from shortening 1-2". So far so good but I do not want a leak! I may ask you some questions when disassembling the floor unit. I have no idea which one is the rearmost unit. I don't think I have one.

[F470]

Too late. I have already forced it in. It's been in for a 1-2 months, I have been on a couple of trips and its holding air like a champ BUT I'm terrified of what will eventually happen so I'm going to follow your advice pronto.

[Attack Ducks]

Originally Posted by F470

I took the floor apart and here are some more photos. Even though it appears from the top that the panels aren't fully flush it turns out the are indeed flush. See photo. One of the panels end pieces is loose and wiggles around and has a crack in it. This concerns me a bit. Should I try to weld this so it doesn't move? There are some holes with what appears to be inserts. Are those steel inserts or just remnant corrosion from some other part? Also there are some corrosion holes. Should I fix those with alumiweld? Not sure there is much else I can do to fit the panels together more snugly. I suppose I could trim the back end panel slightly in order to reduce pressure lengthwise but I am hesitant to do an irreversible modification. I just don't want the thrust board to delaminate from the pressure (it already is in one corner).

On the cracks those are common the military (esp USMC) puts these boats through hell. There was actually a preventative field fix for this called the "CMK" (Craft Modification Kit) which included ONE PIECE SOLID stringers (a single 8-9' stringer replacing the multiple hollow extrusions on each side). John at ACT in Orlando used to sell these along with the other CMK components (aluminum thrustboard reinforcement plates and stainless steel transom reinforcement/cap). If you look close at my "current rig" pics you can see these installed into my boat.

Anyway If you don't plan on throwing 10 heavily loaded troops in your boat and hitting heavy seas then you probably don't need the upgrade and you'll be fine. I personally would TIG weld up the crack just so it doesn't get worse and to clean up the sharp edge that could potentially puncture the boat.

All those holes are from the other random stuff the military or previous owner installed. The most common are a series of holes they laced webbing through to make handholds/footholds. I leave them in place on my boats they are quite handy for securing persons/gear and add more "authenticity" to the boat :-)

[Attack Ducks]

Originally Posted by F470

Wow. Super helpful. I'm in the very same seat as you were. Feels like it is excessively long and that it could benefit from shortening 1-2". So far so good but I do not want a leak! I may ask you some questions when disassembling the floor unit. I have no idea which one is the rearmost unit. I don't think I have one.

The floor consists of four sections, I was referring to the rearmost section. After you knock the sides off look at it from the side and you will see the section is made up of several smaller "planks" that are not all identical (some are longer/wider than the others). You knock out one of the short ones and put it back together. Its been several years since I've had to do this (I'm pretty much out of the biz now) so I can't remember exactly which one but I don't think it was actually the rearmost one but one in the middle. I'd have to go look at my boat to refresh my memory. The rear plank has a smooth back edge, the others are sharp as they are meant to interlock into the next plank. I used to have a stash of extra planks from junk floors but I'm pretty sure I scrapped them.

Also to get the planks separated, I set a 2x4 against the side edge of the plank I wanted to slide off and hammered on the 2x4 so as not to damage the planks. They will slide apart, albeit with great difficulty. Good luck!

[F470]

Thanks! You have been very helpful. I was so worried that I removed two floor sections recently. The thrust board seem to have delaminates a bit where the Hypalon is attached to the board. I can't tell if this has happened over time or if this happened because I forced the floor in. I will take some close up photos and post up so that hopefully you can confirm that everything is as it should.

From what I can gather everything you have suggested so far is correct. I'm hoping that I can knock our the cracked section and put it back together. That way I don't have to repair it which will be difficult. I don't seem to have a rearmost section with a flat back edge. All 4 sections have interlocking edges on mine. Once I get the floor shortened and put back together I'm going to have it sandblasted and anodized back. Then I was planning on getting a black rubber mat to put on top.

[Attack Ducks]

Ok to clarify, the rearmost "plank" should have smooth edges, the inner planks (that interlock front and back) have sharp edges...therefore its best to keep the original rearmost plank and remove from the middle somewhere.

Also I forgot to mention, you will need to cut down the side pieces (the parts that wedge under the tubes) to match the new length. Because the rear corner edges make contact with the tubes at the tube/transom interface it is ESSENTIAL you duplicate the factory radius on the corners and smooth them out so there are no even slightly sharp edges. Cut them at the back ends so you don't have to adjust the stringer stopper positions. I suggest you mark them LH & RH with an arrow pointing to front before you disassemble to reduce the chance of messing this up.

Good luck!

[F470]

Thanks! I'll be a few weeks before I will be able to attack this project. I really appreciate the beta. I have attached some photos of my thrust board. It's delaminating a little bit. Not sure if the floor did this? Should I fix it or leave it? If I fix it what would i use?

[Attack Ducks]

Originally Posted by F470

Thanks! I'll be a few weeks before I will be able to attack this project. I really appreciate the beta. I have attached some photos of my thrust board. It's delaminating a little bit. Not sure if the floor did this? Should I fix it or leave it? If I fix it what would i use?

Yeah thats the early stages. At the trailing edges of the thrustboard you can see the main seam on each side I was talking about. PRAY that's not separating too! (Maybe spray it with soapy water just to check). Its not any easy repair. To it "right" the whole piece of fabric thats loose needs to be removed and reglued which is not an easy or fun job. You "might" be able to inject some glue in there and reglue just the part thats separated but the sucess rate for doing it that way is about 33%. If you do that you must CLEAN IT OUT and DRY IT OUT first. Then toluene clean it (which will be a pita). Then do your best to keep the two halves apart and get glue in there (standard hypalon glue procedure...two coats...20 min to tack after each application...then press together HARD. The issue will be it will be nearly impossible to get the old glue off without complete removal of the loose piece and new glue doesn't stick well to old glue. Hence the low success rate. However if its not air-holding and you take the stress off it, it may be OK.

Another thing you can do while you're in there is try to smooth off the inside rear edges of the thrustboard where they contact the tubes to reduce the abrasion. On some of the boats they left them pretty sharp and over time they start to wear through the boat.

[Aleks]

I know this is a old post. I got two Zodiac FC470 Military versions and I need a floor for them. Any suggestions?

[SoCal Hurricane]

Just sent you a PM. I have the aluminum floors for the boats here in Southern California.