1978 Tri-hull transom rebuild - have question about mixing fillers to lay in the core

[Woodonglass]

Yup, I see what and how you'll be doing the install. Do you have your clamps ready? It's gunna be very important to get good clamping pressure all across the entire inner skin surface to ensure a good strong bond. I don't think the screws are necessary. The Resin and Glass are very strong. I'd use a layer of CSM AND 1708 though. the CSM is just there as a binder for the Poly resin. The 1708 is where you get your strength.

 

[ELoller]

Clamps are ready. I have two sets. Theyre 2x4s that I drilled through the 2 inch side and are long enough to cover the entire core. I will predrill my engine bolt holes and my rear tow eyes before laying the core in. Using those holes I will clamp the 2x4s with precut all thread, nuts and washers that will then cinch up the entire length of the core. I will also use regualr c clamps to clamp the motorwell area down.

The 2nd set of clamps are the same on the inside but I have longer outside ones for when I am clamping the outer skin back on. But now I am considering trashing the old outer skin... thoughts on that? I will need to go buy more 1708 for sure if I am to build up a new outer skin.

 

[Woodonglass]

Have you seen the clamps in this Link? Fabricating Decks, Stringers, and Transoms I think they would be optimal for your installation. I think predrilling your holes is a mistake. To much room for error and need for fidgeting during install. I'd let the PB free flow and fill every hole and nook and cranny that currently exists and then re-drill what's needed. That's just me and you're free to do as you see fit. I WOULD use the old skin. No need not to. you can feather the edges and fill the seam and make it look good when it comes time, we'll discuss the methods for that. I'd guess-ti-mate you'll need about 3-4 yds of 50" wide 1708. How wide and deep is your transom?

 

[ELoller]

I cannot remember the length but it is 1.5 inches thick/deep. I used two 3/4in plywood cores laminated together with CSM.

Im at the office right now. Ill get the length measurement in a bit.

I get your point about drilling the holes and having play while trying to lay it in. Those clamps in the other post look pretty easy to make by modifying my current setup. Ill have to check and see if I have clearance to use them, but I think I do.

Just so I know Im buying the right stuff to cover the inside skin with 1708 cloth here is the link:

http://www.**************************...F4+oz+Mat+Back

I already bought 15yds of 4 inch wide 1708 to complete the outer skin build up. Hopefully that is enough. Thanks Wood!

 

[jbcurt00]

Have you seen the clamps in this Link? Fabricating Decks, Stringers, and Transoms . I'd guess-ti-mate you'll need about 3-4 yds of 50" wide 1708. How wide and deep is your transom?

Just so I know Im buying the right stuff to cover the inside skin with 1708 cloth here is the link:

http://www.************************...erglass+Cloth+-+17+oz+Biaxial+3/4+oz+Mat+Back

I already bought 15yds of 4 inch wide 1708 to complete the outer skin build up. Hopefully that is enough. Thanks Wood!

Since Iboats now sells fiberglass supplies, the server redacts competitor links....

The 1708 you're buying ought to be a WIDE roll of cloth a 4"wide roll of 'tape', as WOG suggested, 50" wide. That way you lay up 1 large piece of cloth, not row after row of 4" wide tape that you need to overlap at every seam.

Take a look at the deck, stringer & transom graphics WOG linked again, in fact, take a look a couple times a day, every day until your supplies arrive.

 

[ELoller]

Haha, yes I get that he's suggesting I buy 50" cloth to layup on the inner skin. I''ll use the biggest pieces I can to tie into my transom core. I see my link didn't work. But I believe it's the right stuff. The 4" roll of tape I bought is for building back up the step grinding I'm going to do in order to feather out my outer skin piece I initially cut with my cut off wheel. I shouldn't need much wider than that to build that back up I don't think.

 

[Woodonglass]

Well I took another look at your pics. Looking at your splash well I don't think the clamps will work and that is a problem in my opinion. It's gunna be difficult to get adequate clamping pressure on the lower center section below the splashwell. As I stated before it's critical that you be able to get got evenly distributed clamping pressure on all areas of the transom. I'm a bit confused on how you're going to be able to accomplish this given your current setup. I guess you set up some kind of exterior support to use to push in against the transom.

 

[jigngrub]

Just a suggestion, but this is the way I'd tie everything back in after the transom is set:



The blue layup with the 3" lap will be your first layup. The 3" would lap over the transom corner and wrap around on to the sides of the hull, the bottom of the boat and top of the transom.

The orange 6" lap would be the second wrapped in the same manner, and the red would be the last.

This will give you a lot of tie-back to the hull and as much area as you need to fair everything out smooth and you don't get that lumped up pile of dog doody look I see with every one of these type builds I see on this forum.

 

[Woodonglass]

This should be of interest to you...http://www.thehulltruth.com/boating-forum/329562-transom-repair-south-jersey.html#b

 

[ELoller]

Great description and graphic Jigngrub! Thank you for that. This helps me plan my supply list as well.

Wood - That was my initial concern before I saw the clamps you suggested. I think I am to back using all thread and pre drilling my engine and tow eyes to cinch down the sets of clamps I have described above.

I am thinking I can mark off sight lines on both sides of the transom core and outer hull during a dry fit and drill the holes. Then Ill just have to line up those lines during the install and the holes will as well. Ill have my all thread and and clamping wood pre staged with a buddy inside to put a wrench on the other side and ill thread the nut on my side and drive it in quick with a drill. That should give me the even pressure I am looking for, I think.

But you raised the point that this will not allow the resin to flow freely like it would without the holes there. Makes perfect sense to me. But what if the bolt holes will be drilled just the right size for the all thread so that should be a tight fit. And I can over mud the PB around them to make sure those areas get plenty of it after the holes get filled in. Ther will be large washers that fit snugly to the all thread as well.

I plan to over drill any holes in the transom and PB them completely then drill to correct sizes after the job is done. The all thread is thinner than the holes I will overdrill to in the end...

 

[Woodonglass]

Still looking at your pics and I'm still concerned with your inner skin and how well it's attached to the sides of the hull. That's where you'll need the strength. 3 layers of 1708 on the outer skin will not provide nearly enuf bulk to fill the void left by removing the outer skin. You're biggest concern, IMHO is to ensure that the connection between the wood transom, inner skin and inside sides of the hull is good and solid. If this is done the rest will be a breeze. Again, that's just my opinion. Others may differ. In the end it's up to you to decide how you want to do this and what works best for you. I'm not actually there and don't know your exact circumstances.

 

[ELoller]

Thru hull Bronze fitting. Can I use this for a bilge drain? I had a factory pressed in aluminum one before I cut it out.

I dont like the plastic screw in ones but I do like being able to take it out if it fails or leaks from some reason.

 

[jigngrub]

How about one of these instead?:

http://www.iboats.com/Seasense-One-...9157877--session_id.607991775--view_id.237498

 

[ELoller]

I looked at those too. But I figure I need a long tube like the original right?

Or will a short one like that work fine if I am planning on over drilling and filling the bilge drain hole with resin then redrilling to the correct size?

 

[jigngrub]

It'll be perfect if you're going to overdrill, resin, and redrill.

 

[Woodonglass]

Before you buy the Garboard Drain you need to measure where the drain tube is located. If its to close to the bottom of the hull on your boat it won't fit correctly unless you want to relocate it and then the hull may not drain properly unless you make some adjustments on the inside. The standard Brass Drain tubes work fine and when installed properly will last for the life of the boat. If you oversize and fill and then install one it'll never cause any problems. You can make your own flaring tool very easily as well. Again... your boat your choice.

 

[ELoller]

You guys are great. Thanks for the advice.

Obviously I am jumping ahead but since it is raining like crazy here for the next few days I have some time to start looking for the final pieces to my rebuild.

Ill take some measurements but I think I have an old Garboard drain without the one-way option on it that is the same size. If it is too big then I guess Ill end up buying the the old school drain tube and the flaring tool if you guys dont think my original suggestion will work?

I have never been that great at making tools and I would rather have the right tool for the job rather than jerry rigging one anyways. Drain tube and flaring tool cost less than I was willing to spend on that bronze thru hull fitting.

BTW Wood, I will take some pics from the inside of my boat to show you the access I have to my inner skin and how I will reinforce it after I lay in my core. I will lay in my core, reinforce the inner skin and tie it into the core better, attach my old outer skin and then work on the finish out of the outer hull.

 

[Woodonglass]

Where are you located. If you want to, you can PIN yourself on our iBoats Members Map


Click Here To Enter Your Location on the iBoats Member Map

 

[jigngrub]

It looks like the bronze thru-hull you posted and the breass garboard I posted are about the same dimensions on the flange, so if one will work the other will work too.

I'm not a fan of the drain tube/ rubber stopper/plug unless the plug can be accessed and installed on the inside of the boat. If the plug is installed on the outside of the boat and falls out it's gone and you're taking on water.

 

[ELoller]

Pinned myself! One more Texan on here!