what height to install the floor at

[bob johnson]

I have seen guys lay their plywood floors out so they need to actually scallop the edges of the plywood to clear the ribs on the underside.... why cant you lay the play wood higher and let if protrude into the inside of the strake fold?? thats a perfect landing for the edge of the playwood. I have a 56 gallon fuel tank and if i stick as far foraward as possible i can lay playwood over it and have it sit on the tops of the ribs....but it almost fits onto that strake platform.....enough to just let it have that ( possibly 3/8" bow up in the middle) rise....

I figure Ill just move the stringers up the ribs to accomodate that level.....seems prefectly reasonable tyo me....but id figure id ask.... this will be my first starcraft floor.

bob

 

[InMotion]

Re: what height to install the floor at

Hey Bob... can't say 100% for sure, but it will likely be quite tight getting the wood in place. Perhaps on your boat it will be fine. I had thought about it too... but ended up opting to stay with laying the floor on the ends of the ribs and 45'ing the edges to get it closer to the outsides. Also, will you be able to rivet/screw it to the ribs if it is up off the ribs? Riveting/screwing to the strake fold would be ummmm problematic!

J.

 

[bob johnson]

Re: what height to install the floor at

well the truth is if the plywood is wedged in tight in that fold...and riveted to the stringers...that would be enough...i wouldnt have to rivet it to any rib...it wouldnt be going anywhere....plus up from for 60 " it would have the support of the gas tank itelf( unless thats a bad idea letting it rest ON THE FUEL TANK?) the width is narrow the more forward you go in the hull...so with the excepotion of the last piece of flooring... I could lay it in faurther back and force it forward under the top lip of the inside of the strake...wedged in there... bob

 

[GA_Boater]

Re: what height to install the floor at

Bob - if you lay the floor on the strake fold and only rivet to the stringers your floor is going to be loose and moving around. Because the way the strake fold is made the wood has to be cut narrow to get it to lay on the fold. The stringers and floor are going to move from side to side. And the stringers will need spacers/shims to raise to the bottom floor level, which adds to the side to side moment and the next thing is popping rivets. And up front it's going to be floating once you get past the stringers. Structurally, I'm not sure its a good idea, in my opinion. I would be concerned about the loss of rigidity.

What about making a raised deck in the front to cover the tank. You could sink it into the floor and that way the height can be kept low. Or go higher and create storage space. Just tossing ideas.

 

[bob johnson]

Re: what height to install the floor at

Bob - if you lay the floor on the strake fold and only rivet to the stringers your floor is going to be loose and moving around. Because the way the strake fold is made the wood has to be cut narrow to get it to lay on the fold. The stringers and floor are going to move from side to side. And the stringers will need spacers/shims to raise to the bottom floor level, which adds to the side to side moment and the next thing is popping rivets. And up front it's going to be floating once you get past the stringers. Structurally, I'm not sure its a good idea, in my opinion. I would be concerned about the loss of rigidity.

What about making a raised deck in the front to cover the tank. You could sink it into the floor and that way the height can be kept low. Or go higher and create storage space. Just tossing ideas.

..ok thats why i am asking...but I did say that I wont need spacers on the stringers as Ill justr rivet them up a little higher on th ribs so they match to underside of the plywood...I am thinking I could add a layer of ply to the bottom of my floor out near the sides so i can rivet to the ribs through the floor, and spacer... and its all solid.... I want to fit this gas tank....but it is about 7/8ths - 1" above the factory floor bottom. if I have to do too much extra work to support the floor( like extra stringers) i might as well, just buy a shallower fuel tank.....but i have this one now...and aluminum tanks run about $400 new. I need a tank with at least 25 gallons.... preferable 30.... so i can cross Long island Sound and come back....i run the same motor I am going to mount on the starcraft , on my 21 foot lowe...which is a shallower V....and i cant make it more than 20 miles before i get low on gas..... from two 9 gallons tanks.

PS wont the sides I install that tie into the floor help keep it in place as well???

bob

 

[classiccat]

Re: what height to install the floor at

Hi Bob, I've raised the floor on a center console using cedar that I ripped down to size so that the sole mates-up with the fold. Attach the ceder to the stringers and the sole to the cedar. Very solid...then again I used 3/4" PLY and glassed top & bottom (pre-iboats). I suppose the downside is that you're raising the center of gravity and making the boat a little less stable.

 

[GA_Boater]

Re: what height to install the floor at

Hey Bob- You can never have too much gas. The side panels might help some since they also tie into the side shelves. I used 5/8 for my floors and 5/8 for my side panels. So that could add stiffness. Something to think about. Maybe a heavy bead of PL on the strake fold before laying the floor. Help bed and anchor the outer edges. That might help.

 

[barato2]

Re: what height to install the floor at

i'm with GA on it being a bad idea to not have the floorboards tied solidly into ribs/sides of hull......the stringers by themselves are pretty flimsy and are designed to work as part of an overall structure, of which floor is an integral part....sorta like one side of the triangle.

what you might could do is make up some L-brackets from sheet aluminum (got any Lone Stars lying around? :lol that would fasten to top of your floorboards and then be riveted to hull maybe 8" above that level so it would be above waterline. this would both reinforce the chine (good idea for ocean duty, i'm told) and tie the floor to the hull.

and maybe budget some $ for tuneup or something on motor? 18 gallons in 20 miles on a flattish vee 21' tinnie is way bad, even if you're blowing along at 40 (i doubt that on LIS) and running a thirsty early-sixties two stroke.

finally, you need to be careful installing alum tanks sub-floor to avoid generating corrosion on tank or hull. someone posted a link here to a good how-to on it and if i can find it, will post.

 

[GA_Boater]

Re: what height to install the floor at

Bob - you might not believe this, but I dreamed about this floor stuff last night. Musta ate one bad tamale too many.

Anyhow, this came back to me.

so i can cross Long island Sound and come back

I'm backing off any suggestions I've made except to install the floors as original. You already took the top off to turn the Islander into an open boat so you've lost some structural integrity. I know you will restore that as best as you can, but adding the raised floor might not so good. Especially since you're planning ocean running I don't think you want a flexible hull, which could be the consequence. The "come back" is an important part of what I'm saying. Barato has a good idea on the reinforcement. Some of the later, larger hulls have something along those lines built in. I just want to help you have many safe, trouble-free trips.

 

[ctswf]

Re: what height to install the floor at

Bob - you might not believe this, but I dreamed about this floor stuff last night. Musta ate one bad tamale too many.

haha no joke I ate jalapenos last night and dreamed about my starcraft too! Only it was bright red, then it was stolen... two bad things

 

[classiccat]

Re: what height to install the floor at

I had nightmares of grade-8 bolt extraction :doh:

 

[bob johnson]

Re: what height to install the floor at

well.....thanks for the replies...... I am thinking this hull is the same hull used on the other boats made during those years..ie the 21 ft mariner and 21 ft ss....so the top portion of the islander isn't needed so much...although it surely adds stiffness,. the other boats must have braces on the sides that tie into the floor......I am thinking I might be able to run box rectangle tube across the tops of the stringers, tieing into the stringers and the top of the ribs as well..... the factory used just super thing strips of aluminum...maybe 1.5" wide X 1/16th" max thick..... the rectangle box of a wall maybe 3/32" would be way stronger...and tie the stringer to the ends of the rib.... then I could fasten the floor to those flat crossmembers, and then the sides to the floor....and id just build a box around the gas tank.....seemingly more work than probably just buying another tank.......if when the time comes to install the tank...I have not found another lower profile tank....Ill go with the crossmembers....I have flotation pods built onto the back of my shallow V aluminum LOWE...the are almost level with the bottom of the hull and are straight back...no angle.....sooooo they drag.... they are great for getting on plane... and for buoyancy when static......but are a big heavily engages trim tab when running!!! so thus the poor gas mileage , I imagine.. the motor is a 95 115 that is running well to 5900 rpms.I am stripping the outside of the boat now....then ill paint and flip her over and then make my decision for the flooring systembob

 

[barato2]

Re: what height to install the floor at

if you have 56 gallons of fuel down at hull level AND have pulled off 250# of superstructure, i don't think you need to worry about your boat being top heavy due to raising floors an inch. and yes, you're correct on that same hull, mas o menos, being used for open boats. but both the SS and Holiday have some stiffening, dash for holiday and consoles for SS, that tie gunwales together or to floor and keep em from flexing. i suspect that the casting deck support in Mairners does the same thing.

interesting on your pods....i hadn't even thought of that issue and would have made any motor pod i made for the Starchief square and mostly flush with bottom. now i know...thanks!

 

[GA_Boater]

Re: what height to install the floor at

Here's a pic from Dozer's SS 201 with the stiffeners on the side. I read somewhere they were incorporated by Starcraft to eliminate cracking in the strake fold. I don't know for sure. I've seen the same gussets in some of the Islander and Chieftain restos here also. I didn't see those in your hull. I think that was what or similar Barato was referring to.

[URL=http://s1184.photobucket.com/user/sv29n/media/Portside012.jpg.html] [/URL]

Those thin strips are just tie pieces for the edges of the floor decking. They aren't structural by any means.

 

[ctswf]

Re: what height to install the floor at

bob johnson have you crossed LIS in an 18' ? Thats something Ive always wanted to do, starting from branford CT, I dont have the balls to do it in an 18' though, not with my 70hp anyway

 

[bob johnson]

Re: what height to install the floor at

bob johnson have you crossed LIS in an 18' ? Thats something Ive always wanted to do, starting from branford CT, I dont have the balls to do it in an 18' though, not with my 70hp anyway

I was in my buddies old starcraft cuddy and we went from the race to Montauk...I think it was an 18.5 footer....high off the water. Myself I have gone across further west in my LOWE ultra Roughneck

, super wide...22.5ft with the pods.....I have been in some rough stuff.....and id prefer more freeboard!!! ha ha ha.....bob

 

[roscoe]

Re: what height to install the floor at

I did similar to BlueFin16.
But....

I replaced the original 1/2 ply, didn't like the springy feeling.
So placed another 1/2 of ply over the top. But I seamed it similar to BlueFin.

This way I was able to cut the ply larger, to fit it into the strake fold.

All the ply was sealed, then the top layer was glued and screwed down.
It looks "more finished" with the floor fitting into the strake.