adding floor ribs

[bob johnson]

anyone ever skip the longitudinal stringers and go with cross bracing or flat ribs to support the floor on their 18 ft starcrafts?

I am thinking of raising the floor( well installed a higher than factory floor, because my boat never came to me with a floor)

my purpose is to install a belly fuel tank and maybe a live well down the center...and save space above the floor for open space as much as possible.


if i ran supports across the top edges of the ribs, I could set the plywood flor down on top and the wood just might run into the recess of the strake runners on each side......seems the floor might be an inch higher or so...id have more space for foam, my fuel tank and live well... leave the step up front for storage and batteries and charger.

anyone ever do this or see it done?

thanks

bob

 

[barato2]

Re: adding floor ribs

Bob--

i think the longitudinal stringers don't just support the floor, they are there for longitudinal stiffness. if you wat to install stuff in the center, what some have done is make new ones further outboard so there's more room between for tank etc. no reason you couldn't still raise the floor. OTOH, i may be wrong on their structural inportance....this one might be worth a call to Starcraft

 

[bob johnson]

Re: adding floor ribs

Bob--

i think the longitudinal stringers don't just support the floor, they are there for longitudinal stiffness. if you wat to install stuff in the center, what some have done is make new ones further outboard so there's more room between for tank etc. no reason you couldn't still raise the floor. OTOH, i may be wrong on their structural inportance....this one might be worth a call to Starcraft

the stringers cant be offering any longitudinal support on their own...they may offer a little if attached to a good solid one piece floor...but since the floor is pieces in usually...I cant see much longitudinal stiffness. I could run my cross braces over the stringers...they are about .06-.075" thick if that!!!

i think the runners on the outside and the keel give most of the longitudianl strength....

bob

 

[barato2]

Re: adding floor ribs

looks like i'll be doing some empirical research on this too. got the floor out of the Holiday this weekend and it looks like i'll have to widen the spacing between the front end of the stringers to fit the fuel tank between em.

 

[Starman8]

Re: adding floor ribs

There is a structural reason why manufacturers have stringers, and they are more than just "nailers" for decking.

The older SS's are not the modern day Superfisherman or Fishmaster designs. The SS loses interior space due to the splashwell designs and the area under the splashwell was intended for fuel tanks, trim pump/motor, and batteries. The SS never considered livewells and additional battery storage because electric motors were not a factor then.

Why fight it?

In the aforementioned newer models, livewells became standard as well as the need for additional storage, hence these newer models have minimized splashwells to allow for useable storage hatches, etc. and added aft decks also.

Accepting this fact, I found the best place for the fuel tank is where it was originally, under the splashwell, then I added an aft deck that created storage and battery boxes as well as a casting platform, but easily converts to seating for two.

 

[barato2]

Re: adding floor ribs

after seeing my stringers, i think Bob ain't entirely wrong on them not adding much structural strength, although on a semi-monocoque design like this, everything that ties together contributes to the overall structural strength.

as a rhetorical answer to your Q "why fight it?"...........
beause we can't afford a Superfisherman or similar newer model.
because we like the idea of our little tin tablas rasas that we can turn into our dreams.
because no one has exactly the same use for a boat and many of them are not exactly the same use as SC envisioned.
because some of us want more than the paltry 18 gallons capacity that SC thought was enough for an afternoon at the lake.
because some of us find that the boat is too durn tail heavy with all the weight in the stern.....you could almost think that SC was worrying more about space in the boat than trim.

i'm keeping my 18 gal under the splashwell but also want additional fuel capacity for fishing the Midriff islands, which is why i'm adding the belly tank. it also does good things for the lowering the center of gravity to put one of the heaviest masses uner the floor.

 

[Starman8]

Re: adding floor ribs

as a rhetorical answer to your Q "why fight it?"...........
beause we can't afford a Superfisherman or similar newer model.

i'm keeping my 18 gal under the splashwell but also want additional fuel capacity for fishing the Midriff islands, which is why i'm adding the belly tank. it also does good things for the lowering the center of gravity to put one of the heaviest masses uner the floor.

I have a 79 SS, wouldn't even consider spending big dollars on a newer tinny

But, the newer models have much wider beams, meaning steeper deadrises, meaning deeper V-hulls, meaning more space under the decking which affords ample space for a below-deck fuel tank.

Longnitudinal stringers are basically more bones in the structure and work in unison with the entire boat to handle and balance loads as well as overall strength. Like some say the keel is the backbone, then the stringers and outer chines work together in similar fashion.

Starcraft also had issues with some 70's SS models whereas several boats failed at the chines fore of midship in the console areas where they cracked from wave pounding. Removing inside stringers from the SS models isn't helping any based on what information is available, but, to each his own, as they say.

When I owned my 2000 SFM, the tank below the deck was nice, but the hull was deeper.

As far as weight, one could always consider battery banks in the floor around the windshield or
an auxilliary fuel tank also.

 

[bob johnson]

Re: adding floor ribs

I am thinking I could actually leave the stringers and run braces right over the top. add more support all the wat around....good for 5 big heavy guys soaking wet in the winter with 200 decoys 2 big labs our personal gear and maybe even 3 -4" of snow that might accumulate during the day!!! that would a lot for a light weight floor!!


bob