Rotten Stringers SC17

[mustangsurvival]

Just bought a 1984 SC 17. My first arima so I am pretty excited as I have spent a long time looking and reading  this site. Thanks to all who have contributed, it has been a wealth of knowledge.
It has a 90 evinrude 1985 that worked flawlessly but when I went over some small chop, I noticed the floor bouncing a little. Plus, there is a small bulge in the floor next to the pedestal seats. The floor seems solid and no rot or delimitation. So I looked in the center floor lockers and noticed some wood in those two inspection holes on the side. It was rotten and fell apart. I could feel foam behind it. I thought there was no wood stringers in the 84 as the factory said "By 1984, stringers were changed over to fiberglass".

Anyway, my plan of attack is to support the boat by the chines then push down the floor from the top to see if I can level it out. If it doesn't move and I think there is foam that expanded in there that made the bulge, then I will probably just leave the bulge.

Then I will cut about 1" below the floor in the center lockers. This should all enough access to remove the rotten wood and prep the fiberglass. Then going to put about 3-4 layers of woven and mat in there  to make a C shape from the front locker to the aft locker on either side. Maybe some triaxial glass too if I have a good bend radius. This C shape for strength and to tie in the deck and hull together. Will make this well strong enough as a fiberglass stringer.  From my measurements, I think I will get a 9' c channel on either side. Unless there is that bulkhead under the seat that I have to butt up against or remove and reglass.
I like this method so I don't mess with that beautiful factory deck. There will be the hatch cover lip left for strength and to support them. I think it's the quickest fix, other than just using it. Don't want to put too much into this, and will want to buy another bigger one very soon no doubt.  Not sure if I will put the boxes back in. We'll see when I get to that.

So I guess my questions are:
Does it sound like rotten stringers?
Does my approach make sense? I have only seen people remove the deck and not just the center boxes.
Of course I will keep you all updated with pictures and progress!

[davidsea]

  Sounds like a good plan - it will be a bit of a puzzle getting the new reinforcements cut to fit and into place for glassing, but your idea of leaving the box lips in place will save a lot of other work, and keep some needed structural reinforcement as well.  It's tempting to cheap out and use standard fiberglass (polyester or vinylester) resin, but I would encourage you to use a quality epoxy system ( like West, MAS or System3 ).  Poly resins work fine for laminating cloth, roving and mat in a boat hull, but they're a lousy adhesive for bonding to existing structure or wood.  It would be a shame to waste your money and labor on something that didn't last.    m2c

[croaker stroker]

I would try and call Don at the factory....See what he thinks. 🤷🏼‍♂️

[amazing grace]

a couple of good suggestions. I want to welcome you and say that I love your pos attitude. It would be easy to have the opposite. With your positive approach I am sure you get it remedied and be good to go for the long haul in your new Arima. Congrats on getting it. 

[Nineball]

I had the exact same condition on my SH.  I watched my floor flex while going over chop.  I approached Don one day and asked for his opinion.  His response was one of three options:

1) don't do anything
2) cut out the bottom of the fish box and glass into the floor (similar to your proposed fix)
3) cut out the floor leaving about 1 1/2" all the way around.  Replace old with new and glass the floor back in.

Of course I asked him if I could separate the liner from the hull.  That was met with a raised brow an a, "well, I guess you could but that would be a lot of work".  Well, I did pull the liner in one piece. It's still in my shop going back together, but I will finish what I started (someday haha).

Your plan is a good one.  Best of luck

[mustangsurvival]

Thanks for your reply's. Its a good point on the epoxy, I will use west systems.

I am glad Rob was ok with the "don't do anything" solution.

How hard was it to remove the liner from the hull? Can you post some pics of what the hull looks like without the liner? What year is your SH?

[Fisherdv]

This may help.....

https://arimaboats.com/construction/

[Nineball]

Sorry for the low lighting

[mustangsurvival]

Your hull looks great! Lots of work I bet.

So I took the fish lockers out. I did the small one first, then the bigger one. I had to cut slits in the ends to be able to slide the box out. The small one slide back and came out easily out of the big hole. I tried using skil saw but was too hard to get right. Best was hand grinder with a diamond blade. The fish boxes are quite well built and heavy, so I don't think I will put them back in. That weight will offset the weight i will be adding to strengthen the stringers.

The stringers started to rot around the holes in the side of the fish box. Port side was the worst but they were both "broken" in a couple of spots and hence why the floor bounced. The bottom half of the stringers were glassed in on either side. I was going to remove the stringer completely, but that is a lot of work to grind all the fiberglass down. I thought about just glassing over the stringer, but then I wont have that much surface area on the deck to get a good bond too. So I am going to leave the bottom third of the stringer in place. The foam will have a nice backing for the fiberglass. The rot was really in the top third and a few small areas all the way to the hull. I was cutting it away with my grinder and i burnt it out. So i took the skill saw and set a 45 deg angle and did a nice angle cut along the whole thing. I will put a bit of filler in there to get a nice smooth transition. Need to buy a new grinder to remove the harder to reach areas and smooth/sand it all.

I am thinking of using a wire wheel brush in lieu of sanding in the hard to get places in the deck, so the epoxy will stick. I looked online and people said there was better adhesion than 80 grit sandpaper. 

the rear bulkhead looked good, but I will strengthen it none the less.

The deck was not boded to stringers in any way, so when I connect the deck to the hull, this will be extra strong. So I may put fewer layers because of this, we'll see.

[mustangsurvival]

Some more pics

[Yachter Yat]

      Sorry, but at the risk of this sounding like a highjack, I thought it might be an opportune time to remind all Arima owners of how important Donny's advice may have been regarding draining these bilges and opening the hatches and access plates on these boats in order to keep these bilges as dry as possible when not in use.  This is a case where moisture is your enemy.     


Yat

[Nineball]

Just remember, it's a 35+ yr old boat.  The wooden stringers and deck underlayment on my '81 SH were made of 1/2" marine ply and NOT encapsulated in fiber-resin.  Also, the closed cell foam will still saturate over time.  I pulled out at least a couple hundred pounds of saturated foam and wood.  The new materials weigh less than 1/2 of the old. I could have still been fishing out of this vessel but I wanted a project, and I got one haha.  But, I am going to finish this one over the winter and hand it down to my 3 sons.  Well, after we use the CRV to haul it around and fish/crab together for a few more years 

Glad you are getting into it so you know what have moving forward.  She will serve you well.  I had my oldest boy sleeping in the cuddy of this boat out of neah bay at 3 years old.  He has been with me every year since then.  Well, he is  almost 18 now and he might miss next year as he has his goals set on the air force.  But this old gem will be there waiting for him when he wants to fish.

[FryFish]

Wow, thanks for posting this. As a newer boat owner, I always thought the bilge was all sealed up and I've been leaving water, sometimes large amounts, down there because I don't have a good way to drain the boat. Won't be doing that anymore

[mustangsurvival]

I cut out some of the rot.

[mustangsurvival]

I supported the boat on the chines then pushed down on the bulge. I didn't want to support the keel cause i wanted it to have the ability to move.

[mustangsurvival]

You can tell I got a bit of force on that beam. Filled in the corners a little bit. I used polyester for this because i didnt want to waste epoxy for something that doesnt need the strength.

[mustangsurvival]

So I am 11.5 hours into the job. Will take 2 more to finish the other side and then about another hour to clean up. I am very glad I got the slow cure west epoxy and its been 4 years since my last fiberglass job. Even though its a slow cure, you are still racing against time to get all four layers on. Its controlled crazyness and the first layer is always the toughest with me thinking it going to go sideways at any moment. Then you keep plugging through it and it turns out ok.

[Wiley]

Great write up and pictures... 11.5 hours is amazing... well done and thanks for sharing 

[davidsea]

  Congratulations, looks like you did a great job.  Your method and structure to push the bulge back into place was genius.  Your first post starting this project was on the 15th, and now, 2 weeks later, you're a few hours from done???   Wow!

[mustangsurvival]

Thanks! I finished quite a while ago but wasn't able to take out to sea trial until last weekend. It handled really well. No bouncing floor and no creaks or cracks when I released the supports. Really happy with it. I added some partitions/bulkheads to maintain the different storage lockers. I painted with an industrial paint, it may peel but I am ok. It was the easiest way to match the colour.

The floor bulge is not perfectly flat, but SOOOO much better.

[mustang65fbk]

Looking good, nice work 

[davidsea]

  Glad you're back on the water, must be a good feeling to be out there and KNOW what's under your feet.  Way to do it right!