1989 BFN Rebuild

Great feed back!

Floor - Planning similar to what you did. From the Ski pole to the dash I would do 3/4" coosa and 1/2" elsewhere. Also, add 1/2 piece at the ski pole. For the removable hatch behind the engine, I am thinking 3/4"x4 glassed and sistered to the secondaries set 3/4" below the top of secondaries (this in lieu of the 90 degree alum angle bar in the original). This will will provide a ridge for a hatch (made of 3/4") to set on.

Stringer height - It is probably wasteful but I measured both the mains and secondaries at their highest. On the coosa sheet layout I was going to cut the along the full length at this width. Then I would use, the ones I removed (managed to get the starboard out with little damage and intact) as a pattern after I put the coosa ones together full length (the scallops would happen in this step). From there, I would do final adjustment/trimming to height to compensate for the floor and some buildup of glass.

Drains - To be honest I really did not put a lot of thought into the drains. If I do it in the aft sections so they would drain into the bilge, how big a hole do you make? Did you fit some kind of tube or small pipe between the stringer and hull to make sure it stayed open when bedding and glassing it in.

Layouts - Fully agree I can get it more efficient. still playing with it...

Engine Cradle - I should have thought of that - it is so obvious! (while i slap my forehead and say "Duh!"). I do have one question though. Did you have to do a lot of adjustment on the engine and xmission mounts to get it to line up properly with the prop shaft? I am going to try an get it as close to original heights as possible but was not sure how close I need to be...

Overall - this was my first cut at a plan so I could get a better idea on materials. I want to shop the material a bit as I have several local suppliers (including US Composites) right here in my "backyard". I did go ahead and buy two 1/2" sheets of coosa ($210 ea) but haven't cut yet - maybe this weekend.

Did you check with composites one?

I'd probably skip the 3/4" in the front floor if I were to do it again. 1/2" wth glass on both sides is plenty strong with supports every 12". The extra care that needs to be taken to account for that extra 1/4" of thickness is a real pain. Doubling up in the area of the pylon where the floor spans the bilge isn't a bad idea, but less of a concern for you than us, as you pylon simply passes through it (ours through bolts to it). 3/4" on the removable panel isn't a bad idea, though we doubled up 1/2" on ours. You might want to add the angle aluminum for support, as holding up that 3' wide panel with only 2 strips of 3/4" seems dicey.

I'd put some thought into your drain plan. Remember that a drain will allow water out of a compartment but it will also let it in... That is the downside to draining everything to the bilge. I have seen inaccessible under floor drains plugged up with debris from the bilge (leaves, etc) and cause a compartment to hold water for an extended period of time. So go with large drains (2" as Pete suggested) on all "blind" drains. On our bfn, we drained cavities together but not to the bilge and it's worked out well for the most part. We left access points that we check periodically instead. Drains between accessible cavities (mains and secondaries for example) can be smaller since you can see that they're stopped up and probe them if necessary (we did 1"). The balloon idea is neat but probably not necessary with the Coosa. Since everything will be pre-glassed prior to install, you can glass them then, or just give them a coat of resin once installed.

Since you're not making any major changes to the main stringers and are reusing your cradle, just put it back in the same place and you'll be fine. There is quite a bit if adjustment In the PCM mounts to allow to align even if you're off a little bit (nailing the lateral location will be more important than the height- but this shouldn't be hard if you're not moving the pylon). We made major changes to stringer width/stance and height, and custom built our cradle (didn't have one originally) so we had a lot more "figuring" to do than you will to get engine placement in the ballpark.

I'd double up the half inch just where it spans the bilge at the pylon. No need to go full width or put 3/4" up front- I'd say it's overkill.

We did not put a drain between the battery box and bilge. I could not find a solution that I trusted that would have been easy to route through multiple bulkheads. We did keep the port hole facing the front as an access point. The problem I reported about the battery box collecting water is true, though it was probably not a major contributor to the water we found in the hull (I later found a small hole from the grinder). I'd probably relocate the access point to somewhere elevated, or at the very least at floor level, so as not to facilitate water intrusion. Having access to inspect and drain those cavities was a great idea nonetheless- I wouldn't consider going without on a boat with sealed compartments.

We removed wood from the keel up front. We made it a little taller and extended it rearward, but no major changes from the original configuration. I think I mentioned adding some blocks to the sides of that piece so as to "catch" the screws from the forward tracking fin- even if remove they wouldn't leave a through hole. If yours didn't have wood there it's probably not critical to add though.