convert soft bottom inflatable to hard bottom dinghy

[xluke]

Hello,
I have an old soft bottom zodiac with a rough bottom. The rubberized coating is peeling off exposing the mesh. I realize one can repair these with rubberized paint but it is relatively expensive and seems relatively fragile.

I was wondering if it would be possible to convert the dinghy to hard bottom by say, taking a piece of plywood, cutting it to form, and laying down fiberglass mat so that it lays nicely over the middle part of the innertubes (beyond the seams) and then epoxy (perhaps with west-system Six10) it to the tubes (I think they are PVC, but could be hypalon)?

Or, any other ideas to repair the bottom?

Thanks!

[CDK]

If it is you opinion that a can of rubberized paint is expensive, forget about turning your old Zodiac into a rib. Chances of success are slim, especially bonding the rigid bottom to old Hypalon.

[pistnbroke]

If you put anything hard into this boat it will chafe with the rubber and cut it ....

[Easy Rider]

I thought of this from a slightly different perspective. I just bought a flex bottom inflatable and used it once. Don't like it. Thought of putting a flexible piece of plastic inside like xluke suggests. Would be nice if one could find a piece of plastic whereas the edges are or could be made more flexible than the rest. One could sand the edges smooth and rounded. One could use a piece of plastic like a Colman canoe but the edge would be most of the time in the same place and wear out the bottom at that point. The white packing foam around the edges may help. I need one of things to work as it's the only dinghy light enough to be easily pulled up on the cabin top.

[CaptBill]

Why not just build a new rib floats and all? Ever seen the foam pool toys, you know the long round ones ? (don't know what they are called) . Well if you could aquire the right diameter of these things from the manufacturer I think you could make the ultimate rib. super light, waterproof, no punctures to worry about. Probably would want to locate a good supplier if heavy duty shrink wrap as an outer casing material. Could even have an inner air chamber to firm it all up when done, deeply centered in the foam of coarse.

[pistnbroke]

I think its what you put around the edge of the ply or plastic thats the trick.... say a length of 1 in dia plastic water pipe split down the side ..thats to make the edge round and then what in australia they call a Poole Noodle ..split the same way if it was nice and tight fit ...blow up after fitted should work easy ... thanks to easy rider for the idea

[CaptBill]

I think its what you put around the edge of the ply or plastic thats the trick.... say a length of 1 in dia plastic water pipe split down the side ..thats to make the edge round and then what in australia they call a Poole Noodle ..split the same way if it was nice and tight fit ...blow up after fitted should work easy ... thanks to easy rider for the idea

A Pool Noodle, exactly.
If you could locate a source on, say, 18-24 inch rounds of this stuff I think it would be superior upgrade from Hypalon. That pool noodle foam is super light, tough, and buoyant. And how simple would it be compared to the construction of a Hypalon tube?

[pistnbroke]

I was thinking of fitting this inside the boat as a new floor ..maybe glue the old one to it or make a sandwitch ..on sheet ply inside one outside ....

[gonzo]

I think you guys are taking a simple idea and making it really complicated to end with a product of less quality. There are soft inflatables, ribs, and hard hulls. Each has good and bad points. Making tubes is fairly straightforward. The trick is designing the panels so they will fit properly. The same can be said for the panels on a hard hull.

[pistnbroke]

but the guy did not want to make a rib he wanted to change it to a hard floor ...what can be simpler than some 1/4 ply and a pool noodle......

[Frosty]

The Zodiac cadet roll up has nylon floor, they are crap the bottom falls out because you cant stick nothing to nylon. I have Just sold a brand new one with the floor hanging out.

I have spent my life trying to make stuff out of bits of this and that. I give up. After a few tubes of sika flex and fugly dinghy that last an hour take my advice and buy a new one or a used one theres more to life.

[pistnbroke]

Fosty Rules

[Submarine Tom]

I couldn't agree more, buy the right boat the first time.

-Tom

[ancient kayaker]

- but he already has this boat and by the sound of it has had it some time.

I agree there would be a concern over the potential for abrasion with a ply floor. My approach would be, first take a look at a RIB boat and see how the problem is dealt with there. I would certainly consider using the idea of pool noodles between the ply edge and the air bags to prevent rubbing.

However if noodles are simply split and fitted on the ply edge that will leave a gap between the ply and the fabric of a few inches. Maybe half-round noodles could be glued to the top of the ply around the edge. Alternatively the noodles could be edge-fitted as suggested previously but some thinner (or half round) noodles added fore-and-aft under the floor to support the fabric.

Any ideas on ply thickness? Based on typical wood boat practice I would suggest about 1% of the beam, but there may be reasons for something else that I don't know about, never having owned a zodiac.

[CaptBill]

My RIB had a scalloped edge conforming to the tube shape. Tube just rested naturally in it slot. and the pool noodle needs to be one super oversized one with a couple v notches at the bow to make the curve. Maybe 18" tubes. maybe a 6-8" center hollow for an air compression tube for some ride control options.
Definitely don't need any sharp edges of any sort.

[pistnbroke]

this is getting crazy ...two posts in one ...we are not talking about making a boat with giant pool noodles but edging some ply with them for a new bottom ...they can be a very tight fit if the boat is deflated when they are fitted and then pumped up ....


Quote ...any ideas to repair the bottom

[CaptBill]

Didn't mean to go off topic. Was more suggesting how simple it might be to do the whole lot just as quick and as easy plus end up with a tougher RIB for no more effort.


edit
..oh you mean just a hard floor.. not building a RIB.Sorry, I was thinking RIB.

[Submarine Tom]

- but he already has this boat and by the sound of it has had it some time.

I agree there would be a concern over the potential for abrasion with a ply floor. My approach would be, first take a look at a RIB boat and see how the problem is dealt with there. I would certainly consider using the idea of pool noodles between the ply edge and the air bags to prevent rubbing.

However if noodles are simply split and fitted on the ply edge that will leave a gap between the ply and the fabric of a few inches. Maybe half-round noodles could be glued to the top of the ply around the edge. Alternatively the noodles could be edge-fitted as suggested previously but some thinner (or half round) noodles added fore-and-aft under the floor to support the fabric.

Any ideas on ply thickness? Based on typical wood boat practice I would suggest about 1% of the beam, but there may be reasons for something else that I don't know about, never having owned a zodiac.

Perhaps he should then sell it and buy the right boat the second time...?

-Tom

[Frosty]

Perhaps he should then sell it and buy the right boat the second time...?

-Tom

Thats what you would do with a car isnt it? I mean if you got fed up with your ford 2 door and you wanted a 4 you would'nt convert it.

[CaptBill]

'cause I likes me some RIB's

[ancient kayaker]

Why do it?

Cost of sheet of ply + few pool noodles + couple hours of work vs cost of another boat (less value of existing of beaten up boat)

not hard to compute; it's cheap and easy, and reversible.


The comparison with a change of car, or house or whatever else you want to throw into the mix is hardly relevant; the amount of work involved in cutting 2 extra doors in a car - well, there's no point in discussing it further really.

This is somethig he can easily do, try it out, then keep if it works or toss if it doesn't. He's looking to us for advice on how to proceed, which we've done, and he also needs a heads-up on unexpected consequences. I've done about as much as I can to help, if anyone has experience with these types of boats and knows of potential problems,please speak up . . .

[Frosty]

Done it been there, its a slight improvement on the slats (emphasis on slight) it still wont plane it just folds up on you because you cant get a full piece in it will neeed to be in 2

even if you put hinges on it. Ive lost count now, wised up. Bought a hard and chocked it on the swim platform. Hard at lunch time soft in the evening, they havnt invented V1agra for dingies yet.

RIP RIB

[pistnbroke]

why does it need to be in two bits frosty ...let the thing down ...put it in ..blow it up ...???

[Frosty]

You have obviously not tried to squeeze one in.

[pistnbroke]

if its deflated where does the squeeze come from its all flopsy bunny ...

forget that when are you on the telly ?/

[sailingdaniel]

A frend of mine found a wrecked rib , got it for free , cut the hard bottom out to fit his old dingy whit soft flor , ripped the soft floor out his dingy. Glued the hard bottom on. It was done in a day and has lasted for 3 years now. it was a succe. l. He used glue from a dingy produser and his dingy was made of hypalon.. I find old pvc hopless to glu so make sure u have a glu thats work...

[Frosty]

Yeah done that too exactly how you described it. I chucked it in the bin a month ago.

[Wavewacker]

I have two inflatables, one is a cloeman kayak, not a bad little boat for a cheapie and a 12' military style, not Zodiak but can't remeber at the moment. I cut out 3/8 ply to form under the tubes above the existing floor, screwed 1x2s on top starting about 2" in from the sides equally spaced sanded the ends forming a taper to the deck at the ends. Paited it with kills. Covered the edges with an old black soaker hose, it's what I had, soft, plyable, cutting a slit in the hose and slipping it on gluing it about every foot (didn't have much rubber glue left). Put it in the boat while deflated. Inflated it the next day and the tube expanded over the edges. Pushed the boat with a 20# thrust trolling motor, worked great. I was concerned that it would pop up in the chop on the lake as it got rough, but it stayed in place taking care.

Now, it's a boat that is hard to carry, car top (truck bed), heavy and afraid to drag it since the bottom won't flex up as it hits the hard floor and may rip or cut from objects, but so far not. It's been used about five times and sits because I don't have a proper trailer. And I knew the kills paint job would not last long, it needs paint now. No noticable problems around the edges.
Kids rode in it being towed with my Searayder jet boat....slowly.

Another project is to do the same thing with the kayak as it's terrible with its floor as is. It will be smaller and lighter to carry too.

That said, I agree with Frosty, I bet no one would buy this contraption for what I have in it or close to it, if at all! I probably should have sold it and gone for what I needed/wanted. A used one off Ebay.

I also used the noodles for stablizers/amas on my canoe. Stuck some aluminum conduit pipe in the length, bent the pipe to form and bent the pipe up to the gunnels and attached with clamps. The pipe went across side to side so I can rotate it changing the pitch in the water. Didn't work too well and looked pretty silly. Perhaps with some fine tuning it could work better but it is functional, that's about all.

[DennisRB]

I have fitted ply floors to 2 different zodiacs which had slats as standard. The performance was much better and it was 5 times nicer to stand in. On one of the zodiacs I had to cut the ply into 2 pieces, it is very hard to get the ply in even deflated. This was a really cheap one from BCF, I would call it a 2 person as with 3 we swamped it. :p

The other one (genuine 3 person Zodiac) I managed to fit one piece in (well the front section which is triangulated still has no ply). This is my girlfriends tender for her yacht. I used marine ply and epoxied it. I made sure to round all the edges and corners first to prevent chafing. I then put strips of black grip tape on it. The result looks really good. It almost gets on a plane now with the 2hp and you get better buoyancy/load carrying as the bottom does not balloon inward. Certainly a big improvement in performance anyway. I'm sure with a couple more HP it would really plane. But the best part is the stable footing.

I would never own one without this mod. The difference is massive (compared to busted slats). Also since they are meant to have slats anyway the rubber is re-enforced in the areas where the ply sheet touches. The slats are cheap compressed particle board or ply and fall apart in a few years. I actually thought of using a shaped pool noodle under the center of the board act as a keel and give even more buoyancy.

[pistnbroke]

Thats great so the aussies can do it and Frosty carnt !!!! Great job dennis

[Frosty]

Frosty can do it Frosty has done it, but its not good enough for Frosty but good enough for the Aussies.

[pistnbroke]

Thats my Frosty ..!!!

[ancient kayaker]

You can never keep a good man down: that's why Frosty's up here and you other guys are down there . . .

[pistnbroke]

No doubt you are down there with us then ,,,,

[ancient kayaker]

No doubt you are down there with us then ,,,,

No, not at present, but I do admit to getting an occasional sinking feeling . . .

[DennisRB]

Frosty can do it Frosty has done it, but its not good enough for Frosty but good enough for the Aussies.

I experienced none of the troubles you had.

For my girlfriends genuine Zodiac I used high quality marine ply. I think 10mm. I cut it in one piece to fit the square section of the bottom. It went in OK in one piece. I have plans to make a triangulated piece for the front section too with some sort of male and female slot system so the 2 pieces will stay together.

With the cheap dingy we only did the ply bottom as we forgot the alloy slats when we shipped the dingy interstate for our Adelaide to Brisbane yacht delivery. So we used the cheapest crap ply possible. It ended up cracking, but still worked fine. I initially cut it in one piece like I did for my girlfriends but there was no way it was going to squeeze in, which is why I had to cut it. However with the cut in the middle it had no tendency to try and overlap or fold. The trick is to make sure it boards are as large as possible so they are a tight fit. If you don't plan on epoxying it, I would put a few layers of duct tap on the edges after you round them to prevent chafing.

I will get pics of the Zodiac next time I am on the boat.

[Frosty]

I experienced none of the troubles you had.


I did not post what troubles I had,-- but---they were too many as you experienced. floppy floors are not acceptable and no matter what, sand and stones get into the edges and cause leaks.

[DennisRB]

Sure Frosty. If you can't get good results, no one can.

Cheers.

[Frosty]

Depends what you want, sure slats are crap and a piece of plywood instead is a better floor but no longer a roll up which is what it was.

If I had a girl friend with a dinghy I would have a look at her slats.