steel stringers

[fiberglass jack]

Has anyone ever used steel for the stringers instead of wood, I was thinking of having a steel frame droped into the hull then glass it in. planing to have the steel custom fit to the hull, cost is not a problem

[bhnautika]

Fibreglass jack I know of a few small yachts that have had steel tubing stringers and framing put in then glassed over, seems to work, some have been around over twenty years. Just watch for rust!

[SamSam]

Somebody asked this a few months ago in another forum and I wondered about the different expansion/contraction properties of metal versus fiberglass and whether the metal might just bust itself loose from the glass or warp the hull different ways depending on the temperature. "Wondered" is the key word, I really don't know how it would work, but sort of think that someone would have tried it by now and if it did work, it would be being done that way for many reasons. The other person was going ahead with the project anyway, I will ask how it is going. Sam
I see this is my 333rd post and I have a "reputation" of 33 for the moment. I better go get a few lottery tickets. Either that or I'm halfway to being evil incarnate.

[Sander Rave]

Hi Sam,

I was thinking exactly in the same direction as you do when reading the post. I'm not sure if the glass or resin is normative for the verification?

[limige]

i was thinking that steel may not flex as much as the fiberglass and may cause the fiberglass to crack..

i have wondered about using composite materials though, like that fake wood sold for decking..


mike

[DanishBagger]

All I could think of when I read the suggestion of encapsulating the steel stringers was "crevice corrosion". I don't think they should be encapsulated, if you want them to live for a long time.

[Milan]

Some quality production boat builders use galvanized steel girder which takes all the loads from the keel, mast and rig. X yachts have a long experience with that system and Grand Soleil uses it at least on some models. http://www.x-yachts.com/ http://grandsoleil.net/ It seems that it works well.

Different expansion / contraction properties are certainly concern but on the other hand, steel girder stays much more rigid under the loads then all fiberglass hull, which flexes much more under the stresses and can develop cracks over the time.

Milan

[SeaSpark]

Steel girders actually are quite common in sailboats as Milan said they take the loads from the keel, mast and rig, we own a 31 year old GRP boat build this way, no problems so far.

In all boats i have seen or heard of the steel was galvanized to prevent corrosion.

[DanishBagger]

Yup, galvanised seems to be the deal here. Especially if encapsulating.

I just read about a boat (in Classic Boat (UK)??) that had some iron stringers or floors. As had the original. That was in a wooden boat.

[SamSam]

Here are some replies this same question is getting in the other forum....

"In my sailboat life i have only seen sections put in for the mast step because the the load is so high it would compresss any wood or glass and the beam spreads it out over a much bigger area

Even on a 24' boat you might have well over 3000 # of tension on the shrouds pressing the mast into the step"
...........................
"Metal stringer are a no brainer. I once owned a 1960s Cheoy Lee Frisco Flyer sloop and it had galvanized steel pipe for stringers and frames. The pipe was glassed in just like any other material. Designed by Art Robb...an architect of highest regard, these were certified by Lloyds of London and bullet proof ocean crossing sailboats. I owned the boat when it was 12 yrs old and there were no problems. The original owner (I bought from) kept it moored off his house in the Virgin Islands. It's rough down there so the boat wasn't a dock queen with easy use. Don't worry about steel stringers being a problem. Glass them right and forget about it."

All the replies have only mentioned sailboats, does anyone know of steel/metal stringers in fiberglass powerboats? Sam