Stringer Question

[atengnr]

OK, sorry about all the saftmate questions lately. Im wondering about the way I did the stringer replacement on my 15 ft back 10 yrs ago. The boat has three stringers, with only the one on the centerline actually contacting the floor over its entire length. The other two (on either side of the center strigner) are 2x4s that contact the floor near the back 5 feet of the boat, boat then do not for the rest of the length of the hull. On this boat, a closed bow, the forward area is for storage. Heres my question...When we ripped out the floor, we noticed that the 2x4 stringers ran about two feet past the passenger area and into the storage area. Now, seeing how much extra work it would be to replace these 2x4s (we opted not to replace the center stringer and thus did not need to rip up the storage area) at their original length, we replaced them only up to the end of the passenger area (thus shortened them by 2 feet).

Did this compromise the structure of the hull?? I cant figure what the purpose of these 2x4s are given that they only contact the floor near the back of the boat, so it seems that shortening them near the front didnt hurt things much...

Thanks for your input.

 

[wire2]

Re: Stringer Question

Are you saying that the outside 2 stringers don't touch the floor or hull after 5 feet from the transom?

 

[atengnr]

Re: Stringer Question

Are you saying that the outside 2 stringers don't touch the floor or hull after 5 feet from the transom?

They touch the hull but not the floor. They are simply glassed into the hull and the hull is flat and shallow enough towards the back of the boat that the stringers contact the floor. After about 5 ft away from the transom, however, the hull side is curved enough that the 2x4s are not in contact with the floor.

 

[wire2]

Re: Stringer Question

Ok, that makes sense. The strength is imparted to the hull, for absorbing the impacts of waves at speed. The floor doesn't get impacts so extra support not needed.

 

[atengnr]

Re: Stringer Question

Can anyone comment on the effect of shortening these 2x4 stringers by 2 feet?? Bad to leave this way or OK?

Thanks.

 

[Ezrider_92356]

Re: Stringer Question

there is alot of strength in a 2x4 without it contancting the floor, i would be worried about it, the bow is what takes alot of the force of larger waves, if the wood in the last 2 feet was still ok and you tied them together good then they are probably ok

 

[atengnr]

Re: Stringer Question

there is alot of strength in a 2x4 without it contancting the floor, i would be worried about it, the bow is what takes alot of the force of larger waves, if the wood in the last 2 feet was still ok and you tied them together good then they are probably ok

No, as I recall, we removed the old stringers and replaced with 2x4s 2 feet shorter than original! So I need to repair this correctly?? How do I minimize tearing up of the floor to accomplish this?

 

[Robj]

Re: Stringer Question

Personally I would not underbuild something compare on how it was originally built and designed. I tend to overbuild, for me it is a liability issue. I cannot say whether your OK or not because I do not know. What I would do is pay close attention to the area and look for signs of failure, it has lasted 10 years. If it was my boat, I would have fixed it with the correct length stringers.

Have a great day,

Rob.

 

[atengnr]

Re: Stringer Question

Can anyone else provide suggests here? Could I remove the floor above the end of the stringers and angle cut the end and then splice in an extra two feet of stringer to restore the original length??

Thanks.

 

[Indymike]

Re: Stringer Question

Here is how I rebuilt my saf T mate.

saf T mate.

I'm not sure I believe that the stringers didn't come up to the sole.

 

[atengnr]

Re: Stringer Question

Here is how I rebuilt my saf T mate.

saf T mate.

I'm not sure I believe that the stringers didn't come up to the sole.

Thanks, your boat appears far better designed than my 1968. The stringer design on my boat would require very minimal design thought. There are no cross braces, and only the center stringer is contoured on the hull side so that the top side is level and remains in full contact with the floor. The side stringers were simply 2x4s glassed onto the hull, and came nowhere close to touching the floor from the front of the boat until about halfway down the length of the boat.

But, as I did the floor removal and improper stringer replacement in 1997, my question is, how should I proceed to repair the rebuilding shortcuts I took?? Im hoping that I can repair this without redoing the project in its entirety.

Thanks.

 

[Indymike]

Re: Stringer Question

You don't mention how the boat feels or performs. I know the front 1/3 of the hull on mine takes quite a beating from other wakes and chop.
As I see it you have two choices...
(1) rip up the sole and repair the stringers properly or...
(2) holesaw some 2" holes and fill with some 2 part foam( 4# maybe ), and hope for the best.

 

[Ezrider_92356]

Re: Stringer Question

maby you can remove just the front 3ft of floor extend the stringers glass it all together and replace the forward part of the floor

 

[atengnr]

Re: Stringer Question

You don't mention how the boat feels or performs. I know the front 1/3 of the hull on mine takes quite a beating from other wakes and chop.
As I see it you have two choices...
(1) rip up the sole and repair the stringers properly or...
(2) holesaw some 2" holes and fill with some 2 part foam( 4# maybe ), and hope for the best.

Sorry. The boat feels no different than it did prior to the project. This boat has been lightly used since 1997, so its no surprise to me that there is no sign of failure due to this mistake.

 

[atengnr]

Re: Stringer Question

maby you can remove just the front 3ft of floor extend the stringers glass it all together and replace the forward part of the floor

Yes, this is what I would like to do, if it can be done corectly. Can I angle cut the end of the stringers and then make a matching cut on the 2ft piece to add on?? How do I bond the two stringers together prior to glassing over?

Is this approach a reasonable method?

Thanks.

 

[wire2]

Re: Stringer Question

Yes, this is what I would like to do, if it can be done corectly. Can I angle cut the end of the stringers and then make a matching cut on the 2ft piece to add on?? How do I bond the two stringers together prior to glassing over?

Is this approach a reasonable method?

Thanks.

Ok, I think I understand your specific question better now. If it were me, I'd cut the existing stringer at 45?, clean the sides 6" in, mate the new 2x4 stringer to it, glue a piece of 3/4 plywood, 3?" x 12" on each side at the joint and clamp tight. That equals 1?" of plywood, will be much stronger than single 2x4. Use marine glue or PL Premium.

 

[Ezrider_92356]

Re: Stringer Question

i would use "peanut butter" to bond the pieces together. i havent even done my own stringer replacement yet, need to figure out a heat source for my garage before going any further. so im not talking from experiance but from what i hear the bond is supose to be stronger than the wood itself so i dont see a problem with doing it this way. the idea of cutting them at 45's in the previous post seems like a very smart idea as well.

 

[atengnr]

Re: Stringer Question

Ok, I think I understand your specific question better now. If it were me, I'd cut the existing stringer at 45?, clean the sides 6" in, mate the new 2x4 stringer to it, glue a piece of 3/4 plywood, 3?" x 12" on each side at the joint and clamp tight. That equals 1?" of plywood, will be much stronger than single 2x4. Use marine glue or PL Premium.

Please note that these 2x4s are oriented with the 4" face on the hull, so their height above the hull surface is 2". How should I proceed in light of this??

What is PL premium? Where can I purchase either of these adhesives??

Thanks alot for your suggestions.

 

[wire2]

Re: Stringer Question

Please note that these 2x4s are oriented with the 4" face on the hull, so their height above the hull surface is 2". How should I proceed in light of this??

What is PL premium? Where can I purchase either of these adhesives??

Thanks alot for your suggestions.

Ah, ok. I was under the impression they were vertically oriented. No matter, then go with 4 pcs of 3/4 ply, 2 x 12, 2 on each side. Still joint the cut in the 2x4 at 45? and glue also.

PL Premium is a polyurethane structural adhesive, comes in caulking gun style tubes, available at most hardware/building supply places, $4-$5 a tube. A seam of it between 2 pieces of wood is much stronger than the wood. Make sure the wood is dry.

You can also use 3M 3200, at 5x the $

 

[atengnr]

Re: Stringer Question

Ah, ok. I was under the impression they were vertically oriented. No matter, then go with 4 pcs of 3/4 ply, 2 x 12, 2 on each side. Still joint the cut in the 2x4 at 45? and glue also.

PL Premium is a polyurethane structural adhesive, comes in caulking gun style tubes, available at most hardware/building supply places, $4-$5 a tube. A seam of it between 2 pieces of wood is much stronger than the wood. Make sure the wood is dry.

You can also use 3M 3200, at 5x the $

Thanks alot. So, should I remove the floor above the area where the stringer length needs to be added, only up to the end of the stringer?? This will allow me to avoid tearing up the portion of the floor that was replaced previously.