Stringers

[markedenfield]

When replacing wooden stringers in a fiberglass boat (19') is it recommended to keep the stringers from touching the hull using spacers? I have read that if you laminate the stringer directly to the hull it will crack the hull when in rough water. However, when you use PB to secure the stringer and then laminate it to the hull, aren't you doing the same thing? The stringer is going to ride with the hull in both scenarios, especially if you laminate the stringer to the transom. As you can see I am new at this and need some help.
I will go ahead and ask a few more questions to get them out of the way before total frustration sets in.
Don't have Douglass Fir for the stringers. I have Southern Pine. Is that ok?
I am using 2X8 for stringers. Is that ok?
What thickness of plywood should I use for the decking?
The boat is a 1996 Moomba Wake Boarding, Ski boat that I am trying to rebuild as a father/son project. Can include pics if I can figure out how. Any help will be great as I am about to cut it up and send it to the scrap yard. LOL
I have not enclosed any pics of before as everything was rotten and imagination will serve well. I don't even have enough stringer left for templates and am having to figure out the angles which has frustrated me quite a bit. Also, is there any need for ribs or lateral support. I know this is like a essay but I don't know how to do this and want to work with my son through completion. Thanks.

Mark

 

[Pmccraney]

Re: Stringers

Good questions; Should be a fun father/son project...

Other more experienced guys can tell you more about this, but I'll go ahead and throw in my .02:

You DO need the spacers on the stringers. Yes, you are technically correct that you still have hardened PL/resin touching the hull. While that stuff dries hard, it still has a little more flex and forgiveness than wood (especially PL).

I think the general guidance is NOT to use dimensional lumber for stringers. I'm not entirely sure of the reason, but I seem to recall its rarely straight and tough to dry out.

On the deck, you could probably use 1/2 ply. If you have a lot of openings for hatches, ski lockers, etc..., then you could bump it up to 3/4. Exterior Grade A-C fir; Aurauco. You can use Marine Grade - its the gold standard, but pricey. I like Aurauco.

Hope this helps.

Good luck,
~rpm

 

[Woodonglass]

Re: Stringers

Yep, ^^^ PMC has given you the correct info. Check out the link in my signature for drawings and recommendations on how to fabricate your Stringers, Deck and transom.

Welcome Aboard!!

 

[mrshake]

Re: Stringers

I think the general guidance is NOT to use dimensional lumber for stringers. I'm not entirely sure of the reason, but I seem to recall its rarely straight and tough to dry out.

On the deck, you could probably use 1/2 ply. If you have a lot of openings for hatches, ski lockers, etc..., then you could bump it up to 3/4. Exterior Grade A-C fir; Aurauco. You can use Marine Grade - its the gold standard, but pricey. I like Aurauco.

Hope this helps.

Good luck,
~rpm

Plywood on edge has more strength than dimensional lumber!

 

[kfa4303]

Re: Stringers

yup and it really only serves as a substrate while the f'glass cures. It's the glass that ultimately does the work, not the wood. Some manufacturers even used cardboard tubing as forms for their stringers back in the day. Be sure you get a proper respirator before you start grinding away and getting f'glass particles in the air.

 

[markedenfield]

Re: Stringers

yup and it really only serves as a substrate while the f'glass cures. It's the glass that ultimately does the work, not the wood. Some manufacturers even used cardboard tubing as forms for their stringers back in the day. Be sure you get a proper respirator before you start grinding away and getting f'glass particles in the air.

Thanks for the info. I'm 99.9% done with the grinding. I used a 1/2 face respirator with a N95 cartridge and sometimes a p100 cartridge. I also had a large volume fan sucking the stuff away from me. Had to wash down the cars in the driveway afterwards. (Whoops).

I've seen the word substrate used quite often. What does it mean in the world of boating?

Mark

 

[Woodonglass]

Re: Stringers

Thanks for the info. I'm 99.9% done with the grinding. I used a 1/2 face respirator with a N95 cartridge and sometimes a p100 cartridge. I also had a large volume fan sucking the stuff away from me. Had to wash down the cars in the driveway afterwards. (Whoops).

I've seen the word substrate used quite often. What does it mean in the world of boating?

Mark

The surface/structure that the new glass will be applied to.

 

[markedenfield]

Re: Stringers

Yep, ^^^ PMC has given you the correct info. Check out the link in my signature for drawings and recommendations on how to fabricate your Stringers, Deck and transom.

Welcome Aboard!!

OK...I've lost the last two responses which were quite lengthy but I'll try again. Thank you everyone for the great information. Without you guys I'm lost and frustrated. I have a few mnore questions.

What is CSM?

What is PL?

I purchased a product called CPES to protect the wood. Good or bad?

Also purchased "Epoxy Fill-It" Good or bad? I was going to use this as the PB.

Now for the long deck and stringer questions. I am (was) using 2x8 Southern Pine for my stringer. I'll change to plywood if recommended. However it's the gradient of the hull angle that has me and my planer baffled. The hull (at the transom) has a 10 degree inward slope and winds up near the bow with a 27 degree inward slope. Trying to match that on the stringer has been nothing but frustration. I feel like my son and I have started a wood chip mill making hamster cage filler. Is this a trial and error deal?

On the decking, I only have a very small section of the old deck remaining (where it met the side of the boat. As told by a friend, I attached a small 1x2 block to the boat and ran a string bubble around seeking a level plane. (Although the boat is on the trailer, I have leveled it out as good as possible. However, when I reach just beyond midpoint, I begin to lose the plane as the boat has an upward movement going to the bow. How do I find a level plane for the decking? If I continue using the current method, I would have to raise the point of beginning about 8" which in this boat is critical with the low sides. I enclosed a photo. About one inch from the gray area into the maroon is where the stringers go.

I think that's it for now. Again, thank you so much for lending me and my son a hand. We have enjoyed what we have done so far (lot's of work) and look forward to completion while doing it right.

Mark and Scott

 

[Yacht Dr.]

Re: Stringers

Had to wash down the cars in the driveway afterwards

Why ? did you have the cars inside of the grind tent ? Do you have pics of the grind tent ?

(Whoops).

Yea ... Whoops is not good enough !!

Thanks for the info. I'm 99.9% done with the grinding. I used a 1/2 face respirator with a N95 cartridge and sometimes a p100 cartridge. I also had a large volume fan sucking the stuff away from me. Had to wash down the cars in the driveway afterwards. (Whoops).

Where do you think that grinding dust is going man ???? Good for you taking your dust mask/respo .. but what about the rest of the kids on the block ??!!!


YD. !!

 

[markedenfield]

Re: Stringers

I appreciate your feedback sir. I live on a 2 acre piece of land and figured with the large volume fan the dust would have dissipated into the air giving it a much reduced concentration than I was having in the boat. Didn't mean any harm.

 

[Yacht Dr.]

Re: Stringers

I appreciate your feedback sir. I live on a 2 acre piece of land and figured with the large volume fan the dust would have dissipated into the air giving it a much reduced concentration than I was having in the boat. Didn't mean any harm.

Fiberglass does not 'dissipate' as you might understand .. and it does not 'reduce concentration' from your neighbors

It does not matter ..
..

I can and will suggest that Anyone Not in a 'contained' way of repair Will affect there surroundings ..


YD.

 

[Woodonglass]

Re: Stringers

What is CSM? Chopped Strand Mat Fiberglass Mat used with Fiberglass resin as the base layer for glassing in the wood.

What is PL? PL is a construction Grade Adhesive that is frequently used to bed the stringers of your boat to the hull.

I purchased a product called CPES to protect the wood. Good or bad? Bad In my humble opinion. Basically it is thinned Expox with the supposition that this helps it penetrate the wood better and thus provide better protection. A Falulty concept. I would retrun it if you can.

Also purchased "Epoxy Fill-It" Good or bad? I was going to use this as the PB. Again I would return it if you can and Make your own PB from Resin, Cabosil and Milled Fibers.

Now for the long deck and stringer questions. I am (was) using 2x8 Southern Pine for my stringer. I'll change to plywood if recommended. However it's the gradient of the hull angle that has me and my planer baffled. The hull (at the transom) has a 10 degree inward slope and winds up near the bow with a 27 degree inward slope. Trying to match that on the stringer has been nothing but frustration. I feel like my son and I have started a wood chip mill making hamster cage filler. Is this a trial and error deal?
Some trial and error but not to bad. Go to a moving company and ask if they have 4 x 8 sheets of cardboard. Cost should be under 5 bucks. If not check with appliance stores for refrigerator boxes etc... cut the cardboard into 12" strip and have your son hold it in place. Take a small block of 3/4" wood and a magic marker, lay the MM on the wood and lay the wood on the hull. run the wood along the hull scribing a line on the cardboard with the MM. Cut out on the line and you should have a real close representation of what the bottom of your stringer should look like.

On the decking, I only have a very small section of the old deck remaining (where it met the side of the boat. As told by a friend, I attached a small 1x2 block to the boat and ran a string bubble around seeking a level plane. (Although the boat is on the trailer, I have leveled it out as good as possible. However, when I reach just beyond midpoint, I begin to lose the plane as the boat has an upward movement going to the bow. How do I find a level plane for the decking? You should still be able to see where the old deck was. Tape a string line from a point of the old deck on one side of the hull to the oher side of the hull and level the string. Now from one of those points run a string to the mid point of the transom and find level and mark that point. Tape string on that point and run it to the bow and level it. That should be your deck. Measure down to the hull to establish your stringer height minus the thickness of your planned decking.

YD is correct about containing the dust as best you can. Fiberglass does NOT dissapate very readily. Just as you should take extreme precaustions, i.e. Full Face Respirator, Full Cover Hooded Tyvek Suit, Gloves etc. You should protect the immediated environment as well. Creating a Plastic Tent to capture the dust and using a shop vac to pic it up is not that hard to do.
Keeps everybody a lot healthier and happier.



I think that's it for now. Again, thank you so much for lending me and my son a hand. We have enjoyed what we have done so far (lot's of work) and look forward to completion while doing it right.

Mark and Scott

See my comments in Red above.
Hope they help

 

[oops!]

Re: Stringers

I appreciate your feedback sir. I live on a 2 acre piece of land and figured with the large volume fan the dust would have dissipated into the air giving it a much reduced concentration than I was having in the boat. Didn't mean any harm.

Hi......Welcome to iboats.

My name is oops and as well as owning a boat repair/restoration company. I help out around the forums.

I apologize for the harsh comments above.
This is not the kind post iboats forum members deserve, and im sure it was made in haste, with out thinking it through.

You are not the first one that has done grinding in there drive way and you wont be the last.

To let you in on what yd is talking about.

Fiberglass dust is permanent. it will not break down.
this is why it is mandatory that proper safety equipment is used, like a good respirator. not just the little dust masks.
if glass dust gets in your lungs, (and it will) the short hairs of the dust are like needles and they actually penetrate the lung and stick into it....kinda like velcro......the cilia (the little hairs in your lungs that constantly clean your lungs) cannot clean these needle like fibers out.

Dont worry, you are not going to die, nor is your 5 year old, nor is your neighbours 5 year old daughter. Its not that bad.
nor will it kill your grass or make the ants in your lawn mutate into giant killer monsters that will devour a town.

Environmentaly speaking, yes.....it is better to place a tarp over your boat and using a shop vac, filter the dust made by grinding.
Then disposed of in the trash.
But you do not need to go rent a 1500 dollar a month shop and equip it with the latest air filtration equipment.

I just have to whip up to the mods forum for a bit, and ill be back to answer your (really good) questions.

cheers
oops

 

[markedenfield]

Re: Stringers

See my comments in Red above.
Hope they help

I "now" understand the lack of dissipation and reduction of concentration. Hopefully, as everyone reads this thread it is understood that it was not done with mal-intent. In fact, I feel horrible right now. I thought I had been following every safety aspect possible and would have never...yes, never knowingly placed anyone in harms way. I have read hundreds of articles with pictures on this forum and although I have seen much fiberglass residue piled in the corners of boats parked in driveways no more than three feet away from their neighbor, I have never read containment articles although I'm sure they are here.

I did perform due diligence with the CDC and NIOSH to find out which type mask and protective gear to use although I admit I missed an important step. Please don't beat me up anymore than I already am.

Thanks for the info on the decking.

 

[oops!]

Re: Stringers

hi

just to further add....i would guesstimate that 50% of the restorations here are done in the drive way.....just like you did...no tarp.

this does not make it politicaly or enviromently correct........but if you were my neighbour, and i came out and saw you grinding on a boat in your drive way........i would climb in and help....not repremand on the dust

 

[Woodonglass]

Re: Stringers

I'm in total agreement with OOPS. I painted my boat hull outside, did not worry about overspray getting on neighbors cars, houses or anything else. It was a nice calm day so I figured it was ok. Was it the best thing to do. Prolly not. So, the next time, I plasticized my garage and closed the door to do the painting. We DIY'ers here on iBoats all "Live and Learn". We had one iBoater make the statement that he pulled his boat "Full of fiberglass dust, down the highway and people thought his boat was on FIRE!!!!!" I think your little bit of dust Whoops on the cars was minor compared to that. Don't beat yourself up over it. I hope my comments in red did not make you think I was upset cuz I was not. Just wanted you to be able to see them. Keep posting pics and questions and we'll be here to help you with all the issues that arise.

 

[oops!]

Re: Stringers

Hi......Welcome to iboats.
I apologize for the harsh comments above.

I hope my comments in red did not make you think I was upset cuz I was not.

lol woodie.....
while i was typing that and editing other posts.....your helpful post snuck in ahead of mine.....yours wasnt the post i was refering to

 

[Yacht Dr.]

Re: Stringers

Please don't beat me up anymore than I already am.

Sorry about my comments up there Mark. Thats not what I was visualizing in my head. I didnt mean to slam on you so hard.

Ever since I had kids, Ive gotten a little Twitchy about these kind of things. I have know peeps that have had bad physical reactions to Fiberglass.

Thank you oops for adjusting my posts..

YD.

 

[oops!]

Re: Stringers

ok.......lets get on with this build !

you seem to be on the fence about what materials to use...poly or epoxy..

you need a little more info here to make that choice.

epoxy resins bond well to everything...however, not everything bonds to epoxy, so you have to chose what you want to use....and stick to it. ie either polyester fiberglass resin (that is what your boat is made of) or epoxy resins.

i would suggest using a polyester resin.

you also mentioned you are having problems with the stringer, matching the curvature of the hull....

in my signature below......there is a link.....click it.....then use the index to find post and scribe stringer cutting.

just follow that along, and you will be ok.

as for the edge of the stringer, meeting the hull,,,,i just take a grinder and whip off a corner of the stringer (knock the outside edge off)

you will need to keep the stringers between 1/8 th and 1/4 inch off the hull of the boat. a popsicle stick is a really good tool for this...
lay popsicle sticks down every so often and place the stringer on those.
then when the stirnger is in place.....use your thickened resin called "peanut butter" to "bed" the stringer.
the recipe for the peanut butter is also in the link below.

make sure you get the peanut butter under the stringer. use a spoon to round the edges of the peanut butter so it is easy to glass to.

im going to leave it at that for now....but i would suggest you do some reading here first, before you do the stringer install.
the first 16 pages of the link below will have you up to speed.
as well, in the how to section at the top of this forum....there is a link to frisco boaters vids on the subject.

if you follow those two sets of instructions, you will have no problems.

please post back often and ask any questions you wish, we will all do our best to help you and your son do this correctly.

by the way........rebuilding a boat is one of the most rewarding things a father and son can do together. so have fun !

cheers
oops

 

[markedenfield]

Re: Stringers

No problem YD. I have made many posts where I came back a day later, read it again and reworded it. When I was the Chief of a large Emergency Medical System, I scribed many memos, letters, general orders, etc. and found that writing them and letting them sit overnight before publishing gave me that fresh start the next day to read them again and edit as needed. Saved me on many occasions. No hard feelings and I now better understand the containment side of things.

Mark and Scott