1972 SN Promo Project

Chris,
The work is looking great Keep going when it gets warmer or get some heat in the garage. FYI, HD has some specials going on now for insulating 2x4 walls!

I started shaping the stringer tops but I'm taking my sweet a$$ time to get them done correctly. As previously discussed, the lip of the old floor will act as a base for the floating floor of the new design. I wanted to make sure that there was a slight angle toward the bilge to encourage water to run to the center instead of pooling on the outsides along the sidewalls. Taking this into account with the potential thicknesses of the glass being layered on the stringer took some time. Most importantly, I wanted to make sure the height and dimension of the engine mounts were being accurately cut for the use of an engine cradle.

I have it marked up and ready for one more series of cuts that will also account for the subfloor around the driver/observer seat. Ill try ti get some video of the progress when it's all fit.

Since the temps have finally taken a nosedive here in Wisconsin, it looks like the CPES, peanutbutter, glassing process will have to wait until spring or early summer.

In the meantime, deconstruction will be commencing on this little guy.


My plan is to tear it down and get it to the machine shop sometime after the holidays. From there I can start gathering the parts needed to rebuild this summer.

The 50" biaxial would be cut into strips. 12' for each side of the primary stringer (24" total) plus enough left over for the cap of each primary.

What type of "cloth" would you suggest for the subfloor? there seems to be 90 choices of "cloth". lol

I also need to re-glass the transom components back in. would I just use normal cloth for that as well? (I.e. - exhaust ports and transom lifting ring mount)

8122pbrainard wrote: Chris, I feel your layup schedule is excessive. Maybe have of what you have drawn?

Its a pretty reasonable schedule, although with actual wood the biaxial might be a bit overkill - you could probably save some resin by using a mat instead - but people are all about the biaxial these days.

75 Tique wrote: I confess. I had to look up CMU. Concrete Masonary Unit. Oh, OK, Cinder block. Well I better grab my ink filled writing implement and get back to work. (impressed now?)

I did the same. Sometimes I don't know about these guys.

Here is my layup schedule.

I plan to make my own CPES to coat the doug fir.

The stringers will be bedded with epoxy mixed with cabosill and 1/32' milled fiber.

Glassing the stringers will consist of 2 layers of 2" tape (offsetting), 2 layers of 4" tape, 2 layers of 8" tape, 1 layer of biaxial 12" thick, and one layer of biaxial to cover the top of the stringer.

Secondary's will get one layer of 2', 4', and 8' tape with a biaxial cover.



Here is my component list so far from US Composites. Please feel free to suggest anything I missed or shouldn't purchase.




The 2 questions I have yet to answer before the materials are ordered, are;

1. what type of mat should I use for the sidewalls of the boat? (under the gunnel)

2. what type of dye should I use for the bilge (assuming I epoxy the bilge).

Hollywood wrote: He's been taking too much or Mr. Tim's advice https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRrfUSsh47ryL63PM7NNenGRLnRrjhsjU95_Vg_KLgU6sU5kpFAAA

They may be stronger stacked vertically as intended but they're plenty strong sideways (and the risk is quite low when the trailer remains underneath).

He's been taking too much or Mr. Tim's advice
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRrfUSsh47ryL63PM7NNenGRLnRrjhsjU95_Vg_KLgU6sU5kpFAAA

I think those straps were a production aid more than any kind of structural member- so I wouldn't go crazy adding too many ribs... just a few to support/provide a nailer for the floor. Maybe 2 per side since you'll be doing a sub floor up front? You'll also want to add a little reinforcement under the lip of the original glass floor that you left behind. With the ski pockets installed it will be hard to put much weight on outer floor edge that the lip is supporting, but it'd be nice to hold some weight without deflection.

Which brings us to the part of the story where planning is involved. I have been consulting with Mr. Tim about the rebuild plan for this boat for quite a while now. As mentioned in a previous post, the current plan is to do a simple system of stringers with ribs, a small subfloor in the cockpit to provide an anchor for the seating, and a floating floor (not glassed to the hull) on the entire boat.

Good plan. You pick up your pylon and clearance bar yet?

Tim had to walk me though the leveling process, but I will post a video of what I did to make sure the hull was straight.

A few weeks ago Mr. Skutch came by to help me acquire some Douglas Fir. The lumberyard was quite mistaken on what they actually had in stock and tried to sell me regular pine. in the end, I ended up getting 2x8x18 for $14.50 per board. Obviously I will end up cutting it all down in the next few weeks.

TRBenj wrote: Ask mars... no foam, ribs or structural floor in his promo. It's solid.

Yep! My Promo is very solid and no issues.   

Ahh... that makes sense...    I do think not adding extra ribs would cause the non-tied surface to be greater (adding the distance from the original floor to the secondary) that could be problematic.   When you add the ribs, the unsupported side area remains the same as the factory design, just a different connection point.     

No stones to throw from my direction, but I am curious about the floating floor idea.    Wouldn't the floor attached to the hull sides provide some stability to keep the hull from flexing while sitting on the trailer, or in a bouncing/choppy water situation?    In my thinking, pressure from the weight of the hull on the trailer bunks would want to bow the hull sides out.   The floor seems like it would provide some stability to keep the hull sides from spreading if it were fastened to the sides.    obviously the hull would be compressed by the water around it, when the boat was floating, so I don't see that as much of an issue.