Not another Mustang restoration thread.

Take a look at a 2001 (cradled) stringer rebuild- the notches below the mounts are 8” long and 2+ inches deep. You shouldn’t need to set the engine down to figure ot where they go.

Are you suggesting you are going to glass the angle in? (Why?)

Stringer height is not that critical- can be a little low (like Pete said you can always shim up). Yes the factory aligned with shims and the wedges at rear.

I’d be thinking about how to accommodate the through bolts at a 15° angle.

Wedge washer would handle my concern just fine.

The large notches/scallops for the through bolting won’t compromise the stringer strength appreciably. I’m sure you’re using a better glass schedule anyways. Leave yourself plenty of room to get those backing nuts installed, it will make your life more pleasant. I must have misunderstood this comment.

john b wrote: Bolt the angle to the stringers and glass them in.

I assume all of this work is happening post stringer install (save for the shaping of the scallops)?

Finally got the first stringer finished. It allows the engine mounts to be through bolted 1.5" either side of the original position. I am starting on the second one this afternoon and hoping to glass them in before the weekend is out. Wish me luck.

John,
I like it. Very nice engineering.

John,
What are your plans for the Coosa sole? After it's layed, with you provide access to the nuts/bolts for the mounts?

Tim might also be referring to the lead in and out of the motor mount bolt notches

john b wrote: I will spend today chamfering the top edges like i did to accommodate the inside curve of the angle stock. Helpful tips are appreciated!

Run over all the edges with the router.

I can tell you're thinking ahead Pete. There is about 2" of cantilever on the floor in that area because the Mustang is a dingy just like that awesome Atom of yours. There is 10" between the motor cover and the side of the hull. If you remember the walkway to the back requires you to walk one foot in front of the other. It is seriously tight. The center of the secondary is 7.5" and the primary is 16.5" from the side of the hull in this area. It may suffice to just bond a piece of Coosa to the bottom of the floor in this area as a reinforcement beam, however I am thinking of this solution. I believe it will clear the exhaust system but it may be tight. The last photo is how I plan to do it if there is insufficient clearance. I plan on having a friend who is a very skilled fabricator make a stainless steel exhaust system with hump hose connection at the manifold and the exhaust tips, so I want to have some room to maneuver the system. Those Holman Moody exhaust maniflods are not at an ideal angle for use in an inboard. As always, suggestions and criticism are welcomed.

I didn’t follow that.

I’d be curious how the floor is being supported at the hull wall and how the mount through bolts will be accessed with the floor in place as well. I’d also want to know how the exhaust would be serviced. How will the floor be attached?

TRBenj wrote: I didn’t follow that. I’d be curious how the floor is being supported at the hull wall and how the mount through bolts will be accessed with the floor in place as well. I’d also want to know how the exhaust would be serviced. How will the floor be attached?

It was suggested earlier that I glass the floor to the hull with multiple layers of cloth rather than making a solid bond. That is what I was planning to do at the hull and possibly using a leger board bonded to the hull underneath to assure it is straight and level. I plan on bonding the floor to the secondary stringer as it was done originally. This is a foamless rebuild. The area between the primary and secondary was left open originally to allow access to the exhaust system with a removable hatch layed on the stringers and held in place by the screws for the engine cover hinge and two screws with trim washers near the rear under the fiberglass rear seat.. It had a stiffener transversely across the stringers for additional support. If I follow the contour of the floor pan I think it will work out fine since it's going back in despite the wear and imperfections. This is not a real restoration, more of a "freshen up and detail". As I said before it will be used as our family boat and sit on a lift in the summer. It's not a garage queen. I'm ok with that. Don't hate on me Pete, but a few things may be a bit different than original like the natural finish of the brass engine jewelry.
The response and help I am getting is overwhelming. This group is amazing.

Permanently attaching the floor as you intend is fine so long as everything is accessible. On such an old/small/thick hull the floor isn’t needed for structural support so it could be screwed down and not affixed to the hull walls as well.

Having the permanent floor follow the shape of the pan is fine and would leave access to the exhaust. This is a good deviation from original where the floor spanned to the main stringer (exhaust was foamed in and glassed over).

How about access to the motor mount through bolts? It sounds like your floor panels will be grabbing the mains for support and may block at least the front mounts, which could be problematic.

TRBenj wrote: Permanently attaching the floor as you intend is fine so long as everything is accessible. On such an old/small/thick hull the floor isn’t needed for structural support so it could be screwed down and not affixed to the hull walls as well. Having the permanent floor follow the shape of the pan is fine and would leave access to the exhaust. This is a good deviation from original where the floor spanned to the main stringer (exhaust was foamed in and glassed over). How about access to the motor mount through bolts? It sounds like your floor panels will be grabbing the mains for support and may block at least the front mounts, which could be problematic.

The photo of the proposed stringer design above spaces the floor stiffener out 1.5" at the aluminum angle allowing about 1.3" of clearance to install the nuts and washers. The angle and bolts/nuts can be easily accessed to check the bolts for tightness and removed if need be for any unimagineable reason. My exhaust was not foamed in. It layed on the floor between the primary and secondary stringers. There was a bulkhead at the front of this area and it was foamed in to the front of the boat. The exhaust was covered only by the removable hatch cover. This allows the entire floor to be open from under the motor cover just behind the pylon all the way to the rear of the boat as shown in the photo of the pan and hatch cover. If you look at the wear marks on the hatch cover you can see there is VERY little room for feet between the rear seat and the motor cover. 10.5" to be exact. I have small feet (no comments please) and my sandals are 12" long.

TRBenj wrote: I can’t make heads or tails of the pics above as to how you’re laying out the floor and its supports near the engine area. The exhaust was foamed in from 66ish until 72, so it sounds like someone dug yours out at some point. The glass floorplan had 100% support underneath from the factory- pretty important because it’s very thin.

It will be suppported 100%. The floor will follow the contour of the pan. I know how fragile these are. I had one from the Mustang SS I sacraficed for the HM manifolds and parts. It was even more fragile because of the large hole for the console. I was driving it home flat on my trailer strapped down well but still a wind gust caught it and broke it in two.
Anything is possible with an old boat like this but I have spoken to every PO except the original who only had it 2-3 years and none mentioned working on the exhaust system. The hose was in terrible shape and looked to be original but who knows on a boat this old. The engine was installed on a saturday and maybe the guys got lazy. I found no trace of foam around the exhaust. In the areas I removed it I pried it out with a wonder bar and had to grind the foam to get it off the fiberglass.
Here are a couple of photos that may make my plan more clear. I admit, those were confusing photos to me, and I know the plan. I did this mockup with a secondary stringer and some scraps so it's a bit crude. The finished product may not be elegant like some of the cradles I have seen fabricated on here, but it's simple, relatively easy, and not beyond my skills with hand tools.

There is a photo back on page 27. I will try to post it here. There was a bulkhead forward of the cross member at the manifolds that is partiall removed. In the well between the stringers you can see the clean fiberglass. if you look between the primary and secondary you can see the gray foam stuck to the glass. It required grinding to remove it. The hose was layed in there and it was dirty but no evidence of foam anywhere, even in the little nooks and crannies.
The piece you see on the stringer is just a Coosa beam to be 3" X 41" and bonded to the outside of the stringer as a support beam for the 5" cantilever at the largest point. It allows a 3" gap to the floor so it is not a closed cell. It should be very strong when bonded to the floor. The entire cantilever area is under the motor box and will not be tred upon in operation. Nevertheless it should be as strong as any other part excluding the back of the hatch that I'm contemplating reinforcing. [/QUOTE]

I hope I'm not posting here too often. Working on our Mustang and following my groups on the interweb is a welcom distraction.
Tim, thanks for the advice on the contour. I may be taking this a bit further than necessary but since I have nothing but time, I have tried to get all the stringer dimensions within 1/16" of the original. It would have been nice to have a router as Pete suggested, but I'm not going out anywhere. I have lots of sandpaper, sanding blocks, and sanders, so I spent a good deal of the day getting it close and contouring the top hand sanding it. Here is where I'm at. If there are no more suggestions or comments I will move on to the port stringer tomorrow. I am checking in to assure this is acceptable work before I copy a starboard mistake on the port stringer. I like working with this stuff. Unlike wood, I make a mistake I can add material.
Thanx.