under deck overhaul on '76 Renken

[blackhawkdown]

Okay, so this is what my boat looks like after removing most of the deck. The stringers are in remarkably good shape so I don't think I need to touch them. I am going to do some extra tabbing though to make them stronger. Here's a couple questions. If I decide to put a fuel tank under deck and cut out part of the middle stringer but put bulkheads and each end will I be messing up the structural integrity of the boat? Right now it has a topside fuel tank that is only about a 10 gallon capacity.
The other thing is something I found interesting. If you look closely to the port side of the port side stringer you'll see what I surmise to be some sort of repair job?? The starboard side of the starboard stringer is not at all like the port side. Could someone have glued down a board and slathered resin over it to fix what may have been a hole? There are no external signs of damage. The two sides are definitely different in looks and depth from the top of their respective stringers. Anybody ever seen something like this?

 

[jbcurt00]

Re: under deck overhaul on '76 Renken

I don't see what you're describing as a repair to the starboard stringer, along the bottom of the pix.

The dark brown along the stringers appears to be water intrusion discoloration, how did you determine that they are solid & don't need to be addressed?

 

[jigngrub]

Re: under deck overhaul on '76 Renken

I agree with JBC, those stringers don't look too sporty to me either.

I'd go ahead and cut them out and replace them since you're already there, I'm sure you'll find some not so nice spots in them near the bottom if you take them out.

The last thing I would want is 37 yr. old stringers and bulkheads in a boat I just restored.

 

[blackhawkdown]

Re: under deck overhaul on '76 Renken

The "repair" is to the left of the port side stringer just underneath the vac hose. It looks a little lighter than the rest of the hull. Let me see if I can attach a close-up photo I have.

 

[Woodonglass]

Re: under deck overhaul on '76 Renken

Huh???

 

[jbcurt00]

Re: under deck overhaul on '76 Renken

I think you are referring to the glassed over piece of wood that runs from bottom right of the pix out from under the vac hose near the red wire, up to about the center of the pix, correct:

totally seperate, and not connected to the port stringer.

I think that's a factory installed hull stiffener for lack of the correct term. And is what the stringers should look like, pale/light in color.

NOT what the stringer shown in the upper right corner of the pix I reposted..... That is NOT a solid, structural stringer, the plywood is delaminating.....

 

[blackhawkdown]

Re: under deck overhaul on '76 Renken

I believe you have the answer jbcurt. Thank you very much, that makes perfect sense. That glassed over piece of wood runs way back almost to the transom at a diagonal. Now the $64,000 questions are a.) did the factory usually put in only one because there isn't one on the other side and b.) what do I do with it? Keep it there and work around it? Take it out. If it's a "hull-stiffener" that would seem like an important thing to have. Kinda' baffling as to why its only on one side!!

 

[Woodonglass]

Re: under deck overhaul on '76 Renken

What have you done to determine that the existing stringers are in fact "In good Shape"??? Unless you drill into them and inspect the drill shavings you will not know for sure their actual condition. I guess my OLD eyes are going bad on me cuz I STILL don't SEE what you guys are talking about. JBC would you please circle in red this hull stiffener you are referring to so I can SEE it too!!!! I'm getting OLD!!!!:facepalm:

 

[jbcurt00]

Re: under deck overhaul on '76 Renken

This is what I was 'seeing' as possibly being a hull stiffener:


Sorry on a public computer out of town.

 

[Woodonglass]

Re: under deck overhaul on '76 Renken

Ok, I SEE what You SEE now...I guess. I would Really like to see a pic of the exterior hull of this Tri-Hull boat and would also like the OP to take core samples of the stringers. I'm not convinced they are "Sound". It would also be good if he could clean up the circled area so we could get a better look at it to determine what it might be and seeing the ouside of the hull would help to see what, if anything it might be supporting.

 

[blackhawkdown]

Re: under deck overhaul on '76 Renken

Thanks to everyone. I'll be working on the boat this weekend so I'll snap some pictures, take some core samples of the stringers and clean out more foam around the "hull-stiffener" to see if I can get it to show up better in a pic. I guess I was hoping more than anything else that the stringers were sound. The fiberglass around them is as hard as a rock, but I guess that doesn't mean the stringer is not soft under the f'glass. I'll also post some interesting pics of the rectangular foam pieces they used back then. I've watched a lot of videos on boat restoration and I've never seen anything like these things. It's a V bottom boat by the way.

 

[jigngrub]

Re: under deck overhaul on '76 Renken

The wood inside the stringers can be mulch and the fiberglass will still be hard. Your boat will be much more seaworthy and safer with new stringers.

 

[blackhawkdown]

Re: under deck overhaul on '76 Renken

After working on the boat I now know why those "hull-stiffeners" are there. Please look at the photos marked port side and starboard side. They are at the exact same spot on the boat only opposite side (obviously). What has happened is that during some repair (maybe) they cut the bulkhead on the port side and instead of putting it back correctly they glassed the end of the bulkhead to the hull and then laid in those boards to stiffen it up. Makes perfect sense only its a half-_ _ _ _ _ job. I also included shots of the bow and a couple pictures of what looks like 2 X 4 lumber but are in fact pre-formed lengths of foam that were laid in next to the stringers in layers. BTW the stringers are rotted out (damm). This is my very first restoration and I've gone farther than I thought I would. Kinda' worried about cutting new stringers.

76 Renken Deck Restoration Slideshow by kbldad1258 | Photobucket

 

[jigngrub]

Re: under deck overhaul on '76 Renken

Check out some of Friscoboaters resto threads, I'm pretty sure he explains how to cut the stringers with pics and videos. Much easier to understand than verbal instructions.

 

[blackhawkdown]

Re: under deck overhaul on '76 Renken

What did you think of those foam forms? Have you ever seen that done before?

 

[jigngrub]

Re: under deck overhaul on '76 Renken

Foam forms? Using foam as a template to cut the stringer by or using foam for the stringer core?

 

[blackhawkdown]

Re: under deck overhaul on '76 Renken

No, the two pictures on the slide show I posted. There was one picture of two leaning up against a ladder and then another of them laying on the ground. I was just wondering if that's how the factory put foam in their boats under the decks back in the 70's rather than use the pourable 2lb foam like is done today? I've never seen that in anybody's video when tearing out their decks.

 

[jigngrub]

Re: under deck overhaul on '76 Renken

Ok, I understand now. These 2 pieces of rigid foam:

Yes, they used to use rigid foam blocks, billets, and sheets back in the early 70's and before. How much of that stuff was in your boat?

 

[blackhawkdown]

Re: under deck overhaul on '76 Renken

Lots. They filled all the cavities beneath the deck. Leaves a lot of dead air space though because of being pre-formed. I didn't know they used them. It made getting the foam out real easy. I guess all the restoration videos I've seen have been for boats the were 80's or newer. I've watched a ton of Friscoboater's videos on You Tube. BTW, once I've got all the foam out and the stringers and bulkheads out is that where I stop or is there sanding to be done also? Looks like there's nothing left beyond that point except the fiberglass that makes up the hull. This is what the bottom looks like.

<a href="http://s827.photobucket.com/user/kbldad1258/media/photo66_zps2cc33832.jpg.html" target="_blank"><img src="http://i827.photobucket.com/albums/zz192/kbldad1258/photo66_zps2cc33832.jpg" border="0" alt=" photo photo66_zps2cc33832.jpg"/></a>

 

[blackhawkdown]

Re: under deck overhaul on '76 Renken

HELP!! Okay, I've got about as close as I can get to the hull with a jigsaw, but there's about about 3-4 inches I can't get because the jigsaw blade hits the hull. What tool do you guys use to get the rest of the deck right up next to the inside of the hull? If it's a 4.5" grinder then what wheel do you use? All I ever seem to see are wheels for metal.