# Photo documentary: Pathfinder 15t stringer rebuild



## dlpanadero (Mar 9, 2016)

Finally got around to rebuilding the stringers on my '99 Pathfinder 15t. I know stringer failure in these boats was a common issue, so I figured I'd post my project on here to help out anyone else who might be considering undertaking the job on their 15 or 17t.

Overall, this is a pretty straightforward project. Good/easy access to everything once you cut the floor/deck out (UNLIKE the ribs/stiffeners up under the front deck, which I've already done.. what a nightmare that was trying to get down there, legs sticking out of the hatch... not fun).

The OEM stringers in these boats were pre-form, foam-core pyramids (PRISMA brand, I think). It seems to me that the underlying issue in their failure was that they simply weren't beefy enough - given the flat bottom of the hull - to deal with the way that most people ran them. (These tunnel hulls are NOT built to be run fast and hard through chop. There's simply not enough V in the hull to displace water and minimize forces - the impact loads transfer directly into the hull with almost no dampening). This probably could have been dealt with if they tied some bulkheads or other transverse frames into the stringer grid, but Pathfinder either failed to consider this or just assumed that no one would ever run them outside 8" of water. Either way, it's a bit brow-raising coming from a name like Maverick. 

There is a bulkhead that runs across the hull directly forward of the tunnel, and it's rock solid, as are the stringers that run aft of the bulkhead all the way back to the transom (I've stuck my head down there with a spotlight and examined all of it). And the hull-to-stringer bond itself is still fine.

I'll see if I can upload some pics here. I've been working on it last weekend and after work for the past week. I hope to have the whole thing done by next weekend (Jan 29), but we'll see...
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## MooreMiller (Sep 10, 2016)

Really nice to see these good pics! Is that a polyurethane pour foam?


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## dlpanadero (Mar 9, 2016)

MooreMiller said:


> Really nice to see these good pics! Is that a polyurethane pour foam?


Yep it's just a 2-part polystyrene liquid foam. That's probably the most enjoyable part of the whole job is shaping the foam lol. And fortunately there's a Fiberglass Coatings here in st pete, so everything I could ever need is a 10min drive away


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## duppyzafari (Jul 9, 2015)

Are you able to re-use the floor after cutting it out? 

That seems like it might be the lone benefit of fully detached stringers - if one exists.


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## dlpanadero (Mar 9, 2016)

duppyzafari said:


> Are you able to re-use the floor after cutting it out?
> 
> That seems like it might be the lone benefit of fully detached stringers - if one exists.


Yeah I'll definitely be re-using the same floor. It's composite core and is in fine shape


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## duppyzafari (Jul 9, 2015)

I don't have a 17t, but I know there are a lot of people who will benefit tremendously from this info. Super cool of you to post this.


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## dlpanadero (Mar 9, 2016)

duppyzafari said:


> I don't have a 17t, but I know there are a lot of people who will benefit tremendously from this info. Super cool of you to post this.


No worries  I always like checking out other people's builds/projects... hopefully this one can be of use to someone out there


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## paint it black (Nov 3, 2007)

Nice post!

This happened to a buddy's 15T twice, and it also happened to another buddy of mine, on his 2002 HPX-T twice. Maverick clearly hadn't figured something out with stringers on tunnel hulls early on.


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## dlpanadero (Mar 9, 2016)

paint it black said:


> Nice post!
> 
> This happened to a buddy's 15T twice, and it also happened to another buddy of mine's 2002 HPX-T twice. Maverick clearly hadn't figured something out with stringers on tunnel hulls early on.


Twice!? Oh no, I don't want to hear that... Hahah. I've never heard of it happening in the hpx tunnel but it doesn't surprise me. I think it's like I was saying these tunnel hulls just have such a flat hull bottom they get beat to death in any kind of open water. It's interesting cos I heard the pathfinder tunnels were designed off of an aluminum boat called a TNT.. It makes since the hull design would work on an aluminum boat since it has more flex, but apparently it didn't work out too well on fiberglass lol.


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## Smackdaddy53 (Dec 31, 2012)

paint it black said:


> Nice post!
> 
> This happened to a buddy's 15T twice, and it also happened to another buddy of mine, on his 2002 HPX-T twice. Maverick clearly hadn't figured something out with stringers on tunnel hulls early on.


I have the 10th HPX Tunnel built and ran her in chop when I test drove it and didn't hear any knocking and the deck is solid. If it was going to fail I think it would have by now. Time will tell because I am rough on boats.


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## paint it black (Nov 3, 2007)

Smackdaddy53 said:


> I have the 10th HPX Tunnel built and ran her in chop when I test drove it and didn't hear any knocking and the deck is solid. If it was going to fail I think it would have by now. Time will tell because I am rough on boats.


Either you got lucky, or he was unlucky. You can ask him yourself. He's a member on here. Really Shallow.


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## lemaymiami (Feb 9, 2007)

I used to run small skiffs hard in rough water..... after I put an aluminum skiff back together for the third time - I learned to run them easier.... No doubt, flat bottomed skiffs take a pounding if you run them hard in a chop - but I was younger then.


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## Backcountry 16 (Mar 15, 2016)

paint it black said:


> Nice post!
> 
> This happened to a buddy's 15T twice, and it also happened to another buddy of mine, on his 2002 HPX-T twice. Maverick clearly hadn't figured something out with stringers on tunnel hulls early on.


Or later on I had tailfisher 05 same issue imagine that it is not a coincidence they don't make that model anymore.My advise is fix it yourself definently DO NOT let maverick TRY to fix it you will be disappointed.


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## commtrd (Aug 1, 2015)

lemaymiami said:


> I used to run small skiffs hard in rough water..... after I put an aluminum skiff back together for the third time - I learned to run them easier.... No doubt, flat bottomed skiffs take a pounding if you run them hard in a chop - but I was younger then.


Running flat bottom scooters almost destroyed my left knee as the hull just does not dissipate any of the shock of hitting rough choppy water. In fact in my majek scooter I busted the front stringers loose in the bow from hitting waves. Just have to work with the limitations of a flat bottom boat if that's what you have. At least with trim tabs can put the bow down and slow down, quartering seas to somewhat alleviate getting beat so bad.


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## fjmaverick (Sep 18, 2015)

What are the first symptoms of stringer problems?


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## commtrd (Aug 1, 2015)

Unusual noise from inside the hull, hull flex, even visually noticeable hull twisting may be seen. Popping and creaking noises likely first indication. May also see soft areas on decks / floors to go with busted stringers.


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## Backcountry 16 (Mar 15, 2016)

fjmaverick said:


> What are the first symptoms of stringer problems?


Mine had cracks in gelcot in the front of the boat on the bottom you could stick your fingernail in it


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## Smackdaddy53 (Dec 31, 2012)

This is a great thread, thanks guys.


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## dlpanadero (Mar 9, 2016)

Saturday update:

Center and starboard stringers raised and shaped to form. I think camfering edges is by far my favorite thing to do. Hand shaped each one w a file and 60grit sandpaper. You know, routine maintenance for any boat owner.

Check out my brothers aquasport in the background of one of the pics.
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## dlpanadero (Mar 9, 2016)

Just saw some of these most recent posts. I've used this boat PLENTY before I got around to doing this project, and I always just took it super easy if there was any kind of chop. Basically idled through it. Every time I'd go out id consider wind direction, and try and fish a sheltered spot where I knew itd be calm. But then again, I'll probly do the same thing once it's done and back in the water..  if you're busting through chop and getting beat to death and it feels like your doing something to your boat that you shouldn't be doing, chances are you probably are, lol. That being said, it will be SO nice having this done so I can actually turn the throttle in a little chop without having to worry. These really are great boats though, despite their limitations in open water. I love the thing, just waiting for that day to come when I can afford a Dolphin super skiff, at which point I'll kick it to the curb faster than a jackrabbit on ice skates


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## paint it black (Nov 3, 2007)

fjmaverick said:


> What are the first symptoms of stringer problems?


Floor flexing, center console moving forward and backwards when running in a chop, my buddy's floor straight up cracked from front to back, and side to side, one day we were in Flamingo.


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## 1shotmike (Feb 23, 2016)

lemaymiami said:


> I used to run small skiffs hard in rough water..... after I put an aluminum skiff back together for the third time - I learned to run them easier.... No doubt, flat bottomed skiffs take a pounding if you run them hard in a chop - but I was younger then.


As you get older, you learn to pick your battles. If it's blowing 90 to nothing out of anywhere, take the flatback and fish where you can. 20' at the waterline cuts a lot of chop. the rest of the time use the micro and fish inside, where they were built for.


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## dlpanadero (Mar 9, 2016)

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Laying a final cap of 1708 over two fully tabbed layers. Note the section on the middle stringer that I wiped out completely. And the white patches are spots of microsphere filler/putty that I spread out and sanded down over rough spots, to ensure the best secondary bond to the hull as possible. Sooo much prep... Ugh. I wonder if there are fish biting anywhere. I had just tied up a fresh batch of magic minnows and half-n-halfs before I got into all this, too. Oh well, maybe the tarpon will be here by the time I finish  Onward to the starboard stringer...


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## dlpanadero (Mar 9, 2016)

And if you're wondering why the center stringer is narrower and a different shape than the outboard ones, join the club. Maybe another one of pathfinders revolutionary experiments in naval architecture. In any manner, all three are now raised to the same height, freshly tabbed to the hull, and thoroughly beefed up


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## fjmaverick (Sep 18, 2015)

Looking good. 

Is there a non-invasive way to check or inspect the stringers? Im probably just paranoid but Id rather be safe then sorry.


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## ol' superskiff (Oct 22, 2015)

dlpanadero said:


> Saturday update:
> 
> Center and starboard stringers raised and shaped to form. I think camfering edges is by far my favorite thing to do. Hand shaped each one w a file and 60grit sandpaper. You know, routine maintenance for any boat owner.
> 
> ...


Now th


fjmaverick said:


> Looking good.
> 
> Is there a non-invasive way to check or inspect the stringers? Im probably just paranoid but Id rather be safe then sorry.


I'd like to know that as well.


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## 1shotmike (Feb 23, 2016)

dlpanadero said:


> View attachment 5498
> Laying a final cap of 1708 over two fully tabbed layers. Note the section on the middle stringer that I wiped out completely. And the white patches are spots of microsphere filler/putty that I spread out and sanded down over rough spots, to ensure the best secondary bond to the hull as possible. Sooo much prep... Ugh. I wonder if there are fish biting anywhere. I had just tied up a fresh batch of magic minnows and half-n-halfs before I got into all this, too. Oh well, maybe the tarpon will be here by the time I finish  Onward to the starboard stringer...


Pretty work, doesn't look like it will ever come apart.


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## fjmaverick (Sep 18, 2015)

Do you plan on increasing the cross bracing? Is that what the 1x4's they put in were for?


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## dlpanadero (Mar 9, 2016)

fjmaverick said:


> Looking good.
> 
> Is there a non-invasive way to check or inspect the stringers? Im probably just paranoid but Id rather be safe then sorry.


Mmm not really that I know of. I ended up cutting the back out of my front hatch liner, and stuck my head down there with a flashlight and you can see the whole underside of the deck, the stringers and everything. But I knew mine were bad before I even visually examined them. It will be quite noticeable if yours are loose - the whole boat will just feel 'soft' when u run through chop. Others have said they heard a knocking sound of the deck slapping against the stringers when running through chop, but I never had this. If you don't want to be cutting any inspection holes, the best thing to do is probably just run it fast through a little chop, and pay attention to how the hull responds. But then again, this is easier said than done because your mind will play tricks on you so to speak... Thinking something is abnormal when it's not, or vice versa. To be honest, if you use your boat consistently and nothings ever really stood out to you abnormally, I wouldn't even give it a second thought. Just go fishing and enjoy the boat. Seriously. And sorry if this thread gave u any suspicions about yours, lol  I did hear that Pathfinder 'fixed' the problem in 2000 and later boats, so keep that in mind too. This one is a '99


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## dlpanadero (Mar 9, 2016)

fjmaverick said:


> Do you plan on increasing the cross bracing? Is that what the 1x4's they put in were for?


I've been giving that some serious consideration. I've been thinking about building up some full-height bulkheads and tying them into the stringers, but i haven't decided yet. If I do, it just means it'll be longer before I can go fishing. And yes, those 4 little ribs in between the stringers are just little hull stiffeners, I 'fixed' those too and re-glassed them, but there's no telling if they actually serve much purpose or not


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## dlpanadero (Mar 9, 2016)

1shotmike said:


> Pretty work, doesn't look like it will ever come apart.


Let's hope not!!


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## zthomas (Jan 14, 2014)

Thank you for sharing this. These detailed pics will be valuable to a lot of people down the road.

I run a '98 17T that was apparently rebuilt by the factory in '01.

FJMaverick, when I look down with a flashlight into the gap between the forward bulkhead and the back wall of the plastic liner in the front hatch, I can clearly see where the stringers have been built up taller. That probably won't tell you much about the condition of the stringers, per se, but you should be able to tell if they've already been re-done or not. I know in a lot of cases, you buy these things used and don't really know for sure if they've been rebuilt or not.

Re: symptoms, as dlpanadero says, if it feels wrong, it probably is. If it doesn't, it probably isn't. But remember that even if the stringers are fine, it's an inherently rattly, flexy, not especially well built boat. I took apart and re-did my hull-deck joint, and it stiffened things up quite noticeably.


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## fjmaverick (Sep 18, 2015)

I have about a 3-4" patch on the floor in front of my center console (almost looks like someone plumbed a livewell). I want to clean that up and during that I might stick a mirror or something in there.

My console shakes terribly. I tightened all the screws and put new 4200 around it. My poling platform also shakes a lot. Theres a lot of slamming going on if I go over a wake (so maybe its the deck cap). I try not to run the boat in any wakes/waves but it happens.


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## dlpanadero (Mar 9, 2016)

Well she came out of surgery successfully and is now recovering with a brand new backbone... I think all 3 stringers came out really nicely and the good weather the last 2 days really helped for a quick and solid cure.

Fashioned some little handles and dry fit the deck back in with the help of a couple people, just to see where I was at. Will be the first of several dry fits before everything is up to snuff for the permanent lay in. Next order of business: refilling the outboard cavities with foam. I'll use a template w some sort of release agent (probably packaging tape ) to get the foam to exactly the height it needs to be, w/o having to do much shaving down. Onward, James.
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## DuckNut (Apr 3, 2009)

Great job you're doing.

What are you going to use to support the edges?


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## dlpanadero (Mar 9, 2016)

DuckNut said:


> Great job you're doing.
> 
> What are you going to use to support the edges?


You mean along the seam where I cut it out? It'll sit on structural foam that's raised up flush with the deck. I'm going to pour foam in that cavity between the stringers and side of the hull


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## Whiskey Angler (Mar 20, 2015)

Smart work. I'm also interested to see your method of mending the seams...I trust it will be effective based on your work so far.


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## dlpanadero (Mar 9, 2016)

Whiskey Angler said:


> Smart work. I'm also interested to see your method of mending the seams...I trust it will be effective based on your work so far.


I'm interested to see how it turns out too, lol. Will definitely be the most challenging part of the whole thing. My plan once the deck is in place and bonded to the stringers, is to fill the seam with putty, grind/bevel everything down about 3" on each side, tape it in place with 2 layers of biaxial cloth, fair everything out as best I can with fairing compound, then gelcoat/non-skid everything. I'll be re-gelcoating the whole deck - I think it'd look pretty bad if I just did the seam


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## dlpanadero (Mar 9, 2016)

Have to postpone progress on the boat til next week due to weather... Booo. Been too cold out to pour foam, which is the next major step. Looking good for late next week


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## jonny (May 1, 2007)

How are you going to bond the floor to the stringers? Plexus? Nice work man it's looking real good. I came real close to buying one of these way back in 2000. Then I started hearing and seeing boats for sale with stringer issues. You should be good for a long long time now.


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## dlpanadero (Mar 9, 2016)

jonny said:


> How are you going to bond the floor to the stringers? Plexus? Nice work man it's looking real good. I came real close to buying one of these way back in 2000. Then I started hearing and seeing boats for sale with stringer issues. You should be good for a long long time now.


I actually haven't decided 100% what I'll use... I was thinking just fc8 from fiberglass coatings. I'd love to use plexus, but I know it's crazy expensive and I'm not even sure where to buy it. Anyone have suggestions? I've got a ton of resin leftover and was also considering just whipping up a putty w cabosil or milled fibers or something. Definitely open to suggestions if anyone's got any input on this one..


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## dlpanadero (Mar 9, 2016)

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Weekend update: Got the foam back in, I think it turned out really well. The stringers are just a hair lower than the foam, but the adhesive putty will account for this. The floor will rest on the foam on the port and starboard sides (as well as be bonded to all 3 stringers), but I need to add a ledger along the underside of the front and rear seam. Try and get that done tomorrow after work, then hopefully be ready to set the deck in permanently midweek. I just want to go fishing!


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## SomaliPirate (Feb 5, 2016)

My 17t is a 2000 model with original stringers and (knock on wood) they've held up fine. I wish I could say the same for the original SleaZ Loader trailer.


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## dlpanadero (Mar 9, 2016)

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Update: floor is back in finally. I ended up using a thickened epoxy to bond the stringers and deck together, and wow it came out solid as a rock. I also ended up bolting in some flanges along the fore and aft seams, as well as in the corners. This gives additional support but more importantly, it really let me lock the deck down to exactly where it needed to be while the critical epoxy bond was curing. As you'll see in the pics, I ended up raising the bulkhead with 1/2" nidacore sandwiched between layers of 1708, so now the floor is supported by all 3 stringers and the bulkhead. Like I said, thing is an absolute rock now and I'm incredibly pleased with how it went back in. Exceeded my expectations. Now all that's left is to bevel down about 2-3" on either side of the seam, tape over it with a layer or two of 1708, fair everything up nice and flush, and then gelcoat.
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## dlpanadero (Mar 9, 2016)

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Well finally got her done. Everything came out really well, only thing I don't like is the white gelcoat... Looks really awkward in contrast to the original faded gelcoat lol. I'll probly end up re-doing it in a few weeks with kiwigrip or tuff coat or something, probably will do a stealth grey or ice blue.

All things considered though I'm very pleased with how the project turned out. Boat is solid as a rock now, and in my opinion is stronger than when it came out of the factory. The difference just standing on the deck is night and day. Cant wait to get it back on the water...


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## dlpanadero (Mar 9, 2016)

Final post... Just got it back out on the water for the first time and oh my GOODNESS, it's literally like a different boat. Night and day difference as far as how it rides/feels. Ran it wide open throttle over some chop out in the bay, and it felt as solid as my 19' hewes bayfisher. Long as it doesn't fall apart now, I'll be quite happy 

Oh, and managed to get a couple really nice trout too for good measure. The one in the pic was about 21".
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## RigaRoo (Aug 14, 2011)

Do you have pics of putting the floor back in? Meaning how you laid that process back up? I'm most likely going to get after this in the future when/if mine fail. They seem to be ok right now


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## matauman (Nov 4, 2014)

Wow, what a great thread, thanks for taking the time to post the pics.


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## dlpanadero (Mar 9, 2016)

RigaRoo said:


> Do you have pics of putting the floor back in? Meaning how you laid that process back up? I'm most likely going to get after this in the future when/if mine fail. They seem to be ok right now


I don't really have any pics of physically laying the floor in, but all I did was spread out globs of epoxy putty on top of the stringers and bulkhead, then had a buddy help me lift the floor and set it back on before the epoxy cured, which permanently bonded the floor to the stringers. Then while it was curing, I bolted the edges and corners to the flanges that you see in the pics. Hope that helps and good luck  feel free to send me a message if you have any questions


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