What to use under stringers

[95 outlaw]

Just was wondering what anyone recommends for under the stringers between the hull. I have read that bondo is no good and am looking for what is used Thanks

[USCGRET/E8]

They are usually just set there and glassed in place...if imperfect, bondo would fill in the gaps before glassing in place I would think...I always made mine to fit and match the bottom contour...

[the1much]

i use a putty called hull & deck, its a poly with fibers in it and kicks off with mekp. its alot stronger then bondo , and bondo usually cracks soo as the boat flexes or the heat from the glass wrapped around it cracks it

[shane blower]

you dont want the stringer flat on the hull do you? im asking because i have the same problem. late 80s boat "glasstron"

[the1much]

what do you mean by "flat on the hull"? ,,your stringers should be "against" your hull, from side to side and the bottom,,,but dont forget ya "water drainage holes" heh

[shane blower]

thanks you just let me know ,i should let someone who knows what there doing do the job

[the1much]

naaaaaaa ,,,its easy,,as long as ya ask plenty of questions,,and dont skimp,,remember that stringers are same as studs in ya house

[shane blower]

yes sir thanks

[charmc]

Shane,

The1much is right; stringers are primary lengthwise supports so they need to be contacting the hull. Marine rated fillers are better than Bondo, which doesn't like water much and will crack when the hull flexes.

Don't call him "sir" when you thank him, though. He won't have any idea who you're talking about.

[the1much]

was he thankin me??,,,,HOT DAMNED,,,i feel old now,,hehe

[ratrace2]

Why not just use aluminium....................

[Landlubber]

Different materials expand at different rates, alloy is totally unsuitable for longitudinals or transverse floor members in a glass boat.

they are simply not compatible materials to frp.

Alloy is great for floor subframes though, they just nest onto stringers that have been glassed into the topsides and onto transverse alloy members on top of bulkheads. you can simply rivet or bolt them together with corner plates or weld the frame together. It is usual to bolt the sections above the engines though as then they can be removed if need be.

[ratrace2]

LL,
OK, I was thinking something along those lines of a problem would pop-up; darn, I,so, do want to eliminate wood from the stringer recipe. Ya know, if you dig deep enough, this boat building stuff starts to require alot of brain power.

But I could" they just nest onto stringers that have been glassed into the topsides and onto transverse alloy members on top of bulkheads", as you say, use alloys i.e. aluminium to bolt bulkheads to the deck from below.


So if I use wood I can't use just any wood....
On the other hand, If I use Rock maple wood, i.e. hard maple, as a stringer that is OK but aluminium is not, Rock maple is harder than aluminium and machines like aluminium.

I have read about wood stringers that were 3"x3"...I think I recall someone recommeding a really large dimension for a stringer in a very (22'), small boat. I could have been a poor recommendation

I need to see the stringer configuration in something like a 37' ft'er.
Also, I need to make some progress beyond Molds, Hull Design and layup schedules I need to get a grip on stringer placement and interior structural components..........
Thanks again LL.

[Landlubber]

If boatbuilding was easy, everyone would be doing it!

[ratrace2]

I think I found the ABS scantling rules. Still can't find the GL.


Rules for Building and Classing Reinforced Plastic Vessels (1978)
Price :40
Publication #: 0012
Description:
These Rules apply to reinforced plastic vessels under 61 meters (200 feet) in length that are intended for unrestricted ocean service. Included in this volume are sections covering materials, fabrication and quality control, tanks, details and fastenings, as well as structures, machinery, equipment, piping, electrical installations, and fire extinguishing systems.

Check this out: This is kind of what I was looking for from the scantling rules research. The information seems a little dated and some the materials would not be used today, but it's got a lot of structural examples that I was looking for....just in case you were wondering what I was thinking when I was asking about scantling rules..

http://www.fao.org/docrep/003/t0530e/t0530e00.htm