Floorboards Lifting

[paul ferraris]

Hi all

I have a Zodiac GR11. The floorboards seem to be lifting (aluminium floorboards). I have two stringers on either side of the floorboards. They are not long enough to cover all the joints in the floorboards so I stagger them. One stringer pushed to the back of the boat and the other is pushed to the front of the boat. The floorboards still seem to push up every now and then. I would like another stringer which I would cut and have an additional shortened stringer on either side. Anyone else experiencing this problem?

Paul

[Peter_C]

The boat was designed to have the stringers set in a particular place. Keep the stringers in their proper place. You must have removed the parts that keep the stringers located properly?

My first question would be do you own a pressure gauge, and if so what pressure are you setting it to? If you do not have a gauge there is your problem, you are under inflated. Without a gauge it is impossible to get the boat set to the proper pressure.

[paul ferraris]

Thanks for the reply. My boat is a 1981 model so does not have any parts keeping the stringers in place at this time. What do the parts look like? Will pump up pontoons harder-also do not have a pressure gauge. Anyone tell me exactly where the stringers are positioned? They are too short to cover the entire floorboard joints so I assumed one should cover the back joints and the stringer on the other side should be positioned more to the front to cover the front floorboard joint???

[Landlockedpirate]

Its just a quirk of Zodiacs of that era. Even when new,with correctly inflated tubes and both the stringers in the proper place it would still flex.

I had a ZED31 new in 1981, mine flexed like mad, especially when 'slightly' overpowered and crewed by 2 'exuberant' teenagers !

My grandad (an aerospace engineer) spent most of the early 80's fiddling with it, his final solution was 2 full length titanium stringers on top of the boards, which would have cost more than the boat and the engine combined (thanks Lucas Aerospace :-) ).

Either live with it or add a couple of extra stringers full length, would suggest 20mm alumiinium box section to avoid dis-similar metal corrosion issues.

[Projectile]

We had a 1981 Mk 2 and Mk 3 Grand Raid. The floorboards NEVER flexed. We had them with a 55 ho engine and in very big water. They never flexed or popped beyond the stringers. We enjoyed these boats fir 3 decades. This is not normal.

The floorboards should have wooden or black plastic (Bakelite?) spacers on them that keep the stringers from sliding forward or backward. With time, these would get loose, come off, and have to be glued back on. Undoubtedly related to the problem you're having, possibly exacerbated by under inflation.

[paul ferraris]

Thanks very much for the info. Please could anyone post a pic of the stringers and where the spacers are meant to be positioned.

Paul

[Locozodiac]

Don't know about Zodiac stringers, but most other brands have rubber stringers endings, if without them will end abrading tube fabric, when sib is correctly inflated to al least 3.0 psi will be pushed against tubes and will help to avoid traveling along to transom or bow when at use.

All medium range inflatables and up have 4 stringers (side joiners) must be placed at X patern :

short, long
long, short
facing each other...

Probably have 2 long ones and missing the short ones, post a pic of your floor set up. Have solved that huge problem years back, now I use 2 long single piece stringers, with well inflated sib gives a fantastic ride...

Happy Boating

[spartacus]

The floor shouldn't flex at all. See diagram. The floor should have rubber points that the stringers locate between.

Pressure for sponsons is 240millibar and 220millibar for inflatable keel (for Tourism, Grand Tourism, etc)