replacement keel

bigscott · 14 July 2010, 20:35

Hi Guys

The inflatable keel in my Zodiac mkII is on its last legs and Ive been toying with a few ideas and was hoping for your input.

1) fill the existing keel with expanding foam

2) fill the existing keel with polystyrene balls ( like bean bag balls)

3) combine 1 and 2

4) build a solid keel like the ones used on the bombard.

Ive also thought about making the keel out of 4 seperate pieces and having them fixed to the bottom of the flooring

Has anyone tried these ideas and how did you get on

zodiacman · 14 July 2010, 22:51

Im having the same problem with my keel and have thought about ways to repair it, I think the only realistic way is to repair the holes with patches or maybe a liquid latex tube sealer. Ive just priced up a new one from Barnet marine £123 inc vat that's for a 4.2 mk2 futura. I cant see the expanding foam or the polystyrene balls working I don't think you could get the keel solid enough with them. good luck anyway and let us know how you get on.

Sharkbyte · 15 July 2010, 00:50

For that price, it makes sense to buy a new one. It has to up to full working pressure for the boat to function correctly.

On my last trip out, mine felt like a different boat for some strange reason. It didn't punch the crests of the waves anything like it should. Pulled up after a couple of miles and pinned it down to the inflatable keel not being right up to full pressure. Couple of pumps, Jesus, what a difference!!!

Out of interest, how old are your boats?

Nasher · 15 July 2010, 11:48

Quote:

Originally Posted by zodiacman

Ive just priced up a new one from Barnet marine £123 inc vat that's for a 4.2 mk2 futura.

Mmmm

I wonder how much the two spare (used) inflatable keels I have in the garage for a 2.8 Zodiac are worth then?

Nasher

spartacus · 15 July 2010, 12:27

Quote:

Originally Posted by Sharkbyte

For that price, it makes sense to buy a new one. It has to up to full working pressure for the boat to function correctly.

On my last trip out, mine felt like a different boat for some strange reason. It didn't punch the crests of the waves anything like it should. Pulled up after a couple of miles and pinned it down to the inflatable keel not being right up to full pressure. Couple of pumps, Jesus, what a difference!!!

Out of interest, how old are your boats?

Definately buy a new one, or repair with 2-part PVC glue and patches. The keel tube wears badly at the stern, where the PVC is folded and bonded (which creates a crease which then leaks due to wear and tear. Can't for the life of me think why Zodiac choose to seal it this way. The keel is crucial to the performance of the boat, poorly inflated will create 'slapping' on the hull underway and lead to potential damage of the PVC floor, especially with 25hp+ outboards.

bigscott · 17 July 2010, 08:11

Sharkbyte my Zodiac is 24 years young

Ive thought about making a solid wooden keel and padding it with foam which will then be bolted to the floor to make it as ridged as possible.

Is the floor in a sib supposed to flex? ( maybe to help with impact)

Poly · 18 July 2010, 00:25

Quote:

Originally Posted by bigscott

Hi Guys

The inflatable keel in my Zodiac mkII is on its last legs and Ive been toying with a few ideas and was hoping for your input.

1) fill the existing keel with expanding foam

2) fill the existing keel with polystyrene balls ( like bean bag balls)

3) combine 1 and 2

4) build a solid keel like the ones used on the bombard.

Ive also thought about making the keel out of 4 seperate pieces and having them fixed to the bottom of the flooring

Has anyone tried these ideas and how did you get on

http://rib.net/forum/showthread.php?...ht=pool+noodle

Sharkbyte · 18 July 2010, 15:54

Hi Bigscott

If only our cars / trailers / outboards cost us £120 in spares, every quarter of a century!!!

TBH, much as I love a bit of modification and DIY, I'd be going for the Zodiac replacement keel at those prices. If the original design was somewhat substandard, and didn't function well, I'd have no hesitation in looking at other options.

SIB's aren't RIB's, and the small amount of flex / give when really hammering one, or getting things a bit wrong ;-), is a feature that I find very reassuring.

There's always the possibility that by introducing too much stiffness, something else will pay the price....quite possibly the floorboards.

Cheers

Wayne

bigscott · 06 September 2010, 13:37

Hey Guys

The inflatable keel is now full of sifaflex, patches and hope with a generous sprinkling of new holes so Ive taken it out and replaced it with 6 pool noodles tied together and it works an absolute treat

the Noodle-keel needs a bit of shaping but its takes the impact of waves nicely and was easy to install. The trickiest bit was putting the floor back but took about 5 minutes and is holding well.

If I get a chance to get out on the SIB today I will try and take a few pics