The crying is over, let the dust fly.

[Firebolt420]

I have a '74 MX 16 and the time has come to tear into the transom. I am in the planning and gathering stage so there is some general confusion for me going on. I store my boat in a friends shop that is not heated so glass work on the boat will happen at my place of employment over Thanksgiving and Christmas breaks allowing me access to a full machine shop and cnc machines while everyone is off for the breaks
My confusion is over the best process for doing the re-transom. I have searched and read so much info that it has become overwhelming. I plan on using poly resin from US Composites and I'm not sure which resin would work best for me and how much I should purchase to assure that I wont need for more during the lay-up. I assume I should use the 435 poly resin and 2 gal of it, but we know where assumptions can get us. The next part of this confusion is what fiber cloth to use and how much of that to use. Cost is a factor, I know it will be around $500ish for materials but I would like to keep it down when possible.
I plan to use a bit of Redstrat's genious design for the transom and elimination of
the splashwell using this plywood http://www.menards.com/main/buildin...-8-marine-grade-plywood/p-1485663-c-13332.htm
and make my adjustments in this way.

The fuel tank will nest between kickers that the "shelves" will attach to. I realize the 19 gal tank will be a lot of weight when full but it will only be full when we are going on river camping trips and the weight will be balanced by personnel and gear in the bow. Any other time it will be around 1/4 full so that will washout itself.


So this is where I am at, let the info flow

 

[topgun]

Dude. She looks good.
The boat is kinda nice too!
Good luck with your project. Seem like we all are looking toward our own projects over the winter right about now.

 

[Firebolt420]

LoL Topgun, my step son says thanks for the complement to "his" project.

I have spent a lot of time ironing out my plan for the Transom and have come up with this as my rough outline and I feel pretty comfortable with it.
I plan on either using some seacast or a thick PB fill on the bottom to get away from the water soaking the bottom of the transom.
Keeping in mind this drawing is NOT to scale or accurate symmetrically, it is just a rough plan to sort my ideas and get some feedback as to the feasibility of this plan.

The transom ply and build ups will be resined and layered 1.5oz CSM then installed as well as the kickers. The water intrusion happened around the splashwell drains and around the garboard drain plug. The bottom of the transom being resin or seacast takes away the water wicking possibility there. As I see it, laying the wood of the transom on top of this before it completely sets it will be a strong seam and be approx 4" deep at its deepest.

 

[Sam I am]

Dude. She looks good.
The boat is kinda nice too!

lol...that was a hanging curve blasted over the centerfield wall.

 

[topgun]

WOW! You guys aren't planning on mess in' around.
I will be cool to see this project as it progresses. Even if the engine IS on the wrong side of the transom. Post plenty of pics.

 

[Firebolt420]

Yeppers, over-engineering can be fun. Really though the only extras I'm adding to the original is the kickers and top build-up of ply. For the kickers I plan on using 1/2" and using a really big hammer to get that motor through on that side
I am going to document as much as I can just because I plan on doing this again on another boat and I know how my memory is.

 

[redstrat]

Count me in Sounds like you're thinking things through really well. I like your schematics. I'm not sure about poly, but epoxy will cure down to about 35℉. Someone pointed out to me that new boats are not allowed to put floatation foam under the deck. It causes the boat to flip over. I found that it sticks to the under side of the deck really well. Just a thought. Are you planning on removing the deck? I'll be keeping a close eye on this project. I kind of have a soft spot for MX's.

 

[nathan]

and let the fun begin!!

 

[Firebolt420]

In looking through my budget and calculating I think I may go with epoxy.
I hadn't heard about the foam not supposed go under the deck, that spot was kind of a last minute idea anyway. Yes, I am pulling the deck too so I will splatter some foam in that direction.
I am also kicking around the idea of borrowing an idea from custom car stereo builders and use fleece to get my initial form for the splashwell elimination. So I'd stretch the fleece to the shape I want and then tape it in and then wet it. after it sets, layer in the 1708 and then mat. Sand out the edges and call it good.

 

[redstrat]

Here is the link to our conversation regarding foam when I was working on my boat.
http://checkmate-boats.com/forums/showthread.php?t=24730&highlight=floatation+foam
Also a link to Coastguard guidelines.
http://files.dnr.state.mn.us/education_safety/safety/boatwater/backyardboatbuilders.pdf

Also. Merton's is very helpful with supplies and materials. http://www.mertons.com/

 

[Firebolt420]

Thanks RedStrat, how much foam did you end up getting stuck in there? I am thinking of making some make shift forms and some good pour aiming I should be able to get plenty in the upper cavities and be very comfy in the end.
I am really glad you are along for the ride on this, you are a huge help in navigating this stuff. Just so you know it is going to be a little slow going for a bit because my job has me out on the road all week and only weekends to throw glass and tear crap up. The demolition is scheduled to begin next weekend and as odd as this sounds I am very excited to start tearing things up.

 

[redstrat]

Here are a few pics of my foam job. I poured foam around the vent tubes in the stern and over a tube in the bow to keep air moving. I had a bit left over so I poured it on the deck. I could have used more on the deck. I can't remember how much I used, I can check my receipts if you like. I figured it out by the Coast Guard recommendations. If you have the original floor you may still have foam under the floor. If so make sure it's not water soaked. Hope this helps. Take your time, your boat has waited 40 years for a little TLC.

 

[Firebolt420]

Sweet, thanks Redstrat, you are a huge help. I must remember next time I am in your neck of the woods I owe you a cold beverage of your choice.
I will do the math on how much foam I will need. I have a calculator for that in one of my bookmark folders.
+1 on this boat waiting 40 years for some TLC and I am glad this boat has chosen me to provide that for it. I can see how this will come out as a diamond in the end by looking at pics of yours for inspiration(which I must confess) I have fallen asleep many a nights with pics of your boat up on the screen

 

[youwont56]

Looks like your of to a good start! I will enjoy watching. I had a little thought about your transom build up. I may be totally wrong here just my thoughts about it. I like the idea of using seacast at the bottom so wood won't have a chance of getting wet. Just remember when cutting out your old transom you leave the glass on the inside to the hight of where you want the seacast to go. Just hog out the wood. So you have a cavity to pore it in to. My main concern is going from seacast to wood transom. I would think you would maybe make a key way in the seacast so you can put a spline in so you would have a mechanical transition from seacast to the plywood. I may be wrong but I would think that could be a place where the wood could brake away from the seacast over time if your just relying on just glue to hold the two materials together. Hope this makes sense.

 

[Firebolt420]

Youwont56, that makes complete sense and I have considered that. I have two thoughts that I am contemplating. The first is to do the seacast and wood at the same time allowing the seacast and wood to bond, The second is what you suggested is to use some kind of mechanical connection like dowels or something like that.
If everything I have researched about seacast is correct I believe that if I go the bonding route it will be a very strong and permanent bond. According to the seacast website it will bond to good wood very well.
Yes I plan on leaving a trough in the bottom between the two skins for the seacast that should be around 4" deep at its deepest.
Thanks for riding along, I am hopping to get into the tear down this weekend or next so my thoughts and plan should get a little more focused after that..... I hope

 

[JT Patroni]

Not sure if it will give you any help but you can look over the resto I did on my Starflite a few years back. Photobucket address in my signature.
May give you some structural info.

 

[Firebolt420]

JT, that is an impressive rebuild you have done there. Thanks, it is very informative and helps a lot. I really appreciate all those pics that show all the details that can easily be overlooked.

 

[Firebolt420]

To the ADD mind....
So I've had some time to play around in paint and get my plan into a form that others may be able to follow. I do realize that all this is WAY over engineered, but this will be the last time this transom will EVER have to be opened up. Even if later down the road I want to play around and throw 350 horses on there Plus if I ever feel like pulling an S-Jumbo barge behind her the last thing I'd worry about is the transom busting out

One of my concerns is in using the brace on the top mount bolts as a NEG buss too will cause some galling or corrosion. I have access to aluminum or stainless for this and will be machined with reliefs and I may even add in a little logo. If I use stainless it would it also be tapped and utilized as the attachment fastener. Also would there be too much stress on brace A if the motor mount and stern eyes are through it?

I also have done away with placing the batteries in the transom area and decided to place them in the bow.

All thru transom holes will be drilled .25 over and filled with epoxy then drilled to size, except the garboard drain which will be thru the Seacast.

So the demo should be starting next weekend and continue over Thanksgiving break and then the smaller parts and supplies will be purchased and fabricated. My goal is to be putting together everything over a weekend in February or early March. This will involve trailering her to the shop and pulling a marathon layup session My concern in carrying out this plan is when I do all this glass, how long does it have to be in 75-85 degree temps? It would have as I estimate from Saturday afternoon until Sunday evening to initially cure in the temps. Then it would have to go back to winter temps. This would encompass all the heavy work then the smaller tasks could be done at my leisure on my weekends home ending in a final goal of splashing sometime in early May


Brace B will follow around just under where the brace is now but will be attached to the top of the bottom.

My purchase list looks like this;

1. 2 sheets 3/4" ply
2. 1 sheet 1/4" ply
3. 14 yds 1.5 CSM
4. 10 yds 1708
5. 10 lb 1/4" CS
6. 4 gal Cabosil
7. 1 gal Seacast
8. 3 gal Epoxy
9. 28"x4"x3/4" Bar AL or SS Scrap bin.
10. 1 sheet 1/2" ply

All ply parts will be epoxied and then wrapped with CSM for waterproofing. The transom wood will be done this way, then when the A and B braces are tabbed and filleted in it will all be covered in 2 layers of 1708. That is when the kickers, covered in 2 layers of 1708 will be tabbed into place.


SOooo.... Is there anything I'm missing or completely overlooking?

Does anybody know that cabosil is also an ingredient in a lot of different pills for the purpose of cutting small slits in the stomach lining so that the medication can be more quickly absorbed into the bloodstream?

And yes, there is never a dull moment in my brain.....

 

[redstrat]

Looks good to me Keep in mind that epoxy does not like CSM. You might want to consider a 6oz mat or a stitched mat.
http://www.mertons.com/Reinforcements/cloth.html
http://www.mertons.com/Reinforcements/double_cloth.html

Another tip I picked up was to lay out your transom template on the diagonal when you transfer it to plywood. If you laminate ruff side to ruff side the grain will create on X pattern for optimal strength. Oh yea, be sure to buy the pumps for measuring epoxy. I used a lot of cheep wooden brushes ( Harbor Freight ). Cut the bristles to about 2/3 length. The nice thing about epoxy, no stink.

 

[Firebolt420]

BBBZZZZZzzzzzzz

Huh... Oh nap time is over?

Ok, so life stepped in and rearranged the projects and priorities around me. Big things have changed.

#1. We have relocated to South Carolina

#2. I now have the boat right outside the back door

In all the excitement and chaos of moving and keeping up with work I have really been at a loss for posting so for that I apologize

I am going to be getting a metal temp garage to cover and shelter my work when the weather gets really cold here

I will be posting pics of the new home for the girl and I have printed of the list of materials for an outboard stand that I hope to start tomorrow. I am shooting for the goal of having the splash happen mid May. With my work schedule being the same in the way that I will only have weekends at home so planning and FOLLOW through is critical

I have been searching my new area for any B&M shops to purchase most of my supplies of resin and cloth. I had a line on several in my area back in MI. but no more. I of course have the common big box hardware stores I will be hitting for my wood type materials. If anyone knows of any gems in the Augusta, GA. and Aiken, SC area please sound off, loudly if need be.