Using Seacast or similar with 5in" Tarnsom Increase

[Rybones]

Hi All, I know this is a can of worms topic. I have read all the forums and talked to a few end-users as well as a manufacturer. I have talked with old school guys on both sides of the coin, that it's acceptable and that it's an abomination. I'm leaning to it's acceptable in specific applications and only if done absolutely correctly. Meaning removing ALL wood and properly preparing the surfaces for a proper bond. It is a 1974 20-foot SF with 2 stroke 150 with a 5" setback hydro JP. The boat is all original, unmolested and all the glass is in absolutely excellent condition. I want to keep it original and not cange anything except transom height. But I know I have some rot around the engine bolts in the transom and I'm getting a nominal amount of flex in that area also. So something needs to be done about it. What I would like to do is go with Seacrest or Nida Bond or Arjay, but I also want to raise my transom notch by 5" as it's the old 20" in transom and I want to go to a 25" in transom. I'm looking for recommendations or better yet instruction on how to create the skins to fill it up 5 inch Gap between the transom I have and the transom I want. I need to create and install the skins and form it to pour the seacast or similar product. I'm good with the preparation of the transom and the pouring of the seacast but I hope there's someone in this form that has done specifically this before and will give me step-by-step instruction as to the fiberglass skins and forming. Plus specific materials, amounts and tools I would need for the fiberglass aspect.

I know there is a tremendous ammount of knowledge here and opinion here but I'm not looking for dicussion of if its right or not, I am simply looking for information on how to raise the transom and glass with porable product.

Thank you all inadvance for your input.

Cheers, RyBones

[jorgeinmiami]

I used Arjay and raised the transom 6 inches

Easier than what I thought

[Rybones]

What did you do for glassing in the 6" extension?

[jorgeinmiami]

When I took the floor off I saved some of the skins and cut them to size and glassed them in. You can always make some yourself using mat and building it to the right thickness.

[Rybones]

I'm trying to figure out how to keep from having and indent from any difference in fibrglass thinckness between the existing hull and the skins.

So when I make the skins, how much bigger than the area I want to cover do they need to be?

And how much should they overlap the existing glass?

Is it correct in assuming that the skins are to be placed on the inside?

After glassing in a flat skin from the inside, do I cut a peice(s) of mat to the exact same size as cut out area I'm trying to fill? (to incrase the thickness on the exterior to match the hull thickness?)....

Or... can I simplify my process and put a board or form on the outside and just make a skin in place on the inside that I be sure to tuck into the edges of the cutout extreamly well and very wet so the thickness looks right on the outside. (Im saying that keepin in mind, that the inside filler product being pourable, doesnt need to be smooth or even plane on the inside as if you were bonding to a ridgid peice of wood or composite.)

Do I need to glass in or tab them on the out side also or if I prep the outside of the existing glass/hull properly and put them in wet enough will that suffice?

As for the glassing back over the top/cap edge, I was thinking that before I pour I would glass 6" biaxial tape all along the inside top edge of the opening that I would fold back over the top edge after I pour to cap the top edged of the transom. Sound right, make sense?

What kind of glass mat do I need to make the skins?

What type/weight of glass tape should I for the cap edge?

what type of resin should I be using?

After that I assume that I need to sand it, fair it, sand it again and gelcoat it..?

Anybody that wants to chime in and respond to these questions point by point or offer any other advice please do so. Thanks Jeorge and everyone for your insight and help.

[DonV]

Seems to me you are not very experienced on this type of work. This is not something you want to do for your first try and have it not work out. I can see re-coring a hatch for your first try working with fiberglass, however a transom is a different and much more important undertaking. Have you checked around for pricing from a professional?? You are going in the right direction with the 25" transom for sure.....

[Rybones]

Thanks for responding DonV. You are correct, I have very little experience with glass and even less with transom repair. I take if from your, albeit curtious but disaroving tone that you have very little faith in the pourable route. I have spoken with a few professionals. 2 of whom said that they would do it with wood or composite and glass and two said that done properly in my case would be fine to go with the pourable (the latter two were not advocates or realted to any of the porable products). I also saw a whaler transom that a friend did on his boat about 7 years ago with pourable that came out nicely and is still perfect. He is not quite as perticular and meticulis as I am and had the same or less experience that I do. Yes, I know that "just because it worked for him doesnt mean it will work in my case". However the original structural integrity of all glass and stringers has been surveyed and is still uncompromised as yet. I am confident that with the proper planning, preparation and input from people like yourselfs that this can be compleated with no compromise in saftey or integrity. I am in the planning and fact finding stages so you can clearly see the level of my experience. I will say, I have yet to see one example of a porable DONE PROPERLY with all other structural integrity intact, fail. DonV, I have read your posts for years and seen the tramendous ammount of insight and experience you lend to this fourm, have you worked with a porable product or have an instance that you personally know of an instance that it has led to failure be it catistrophic or other wise? Or is it simply my current lack of knowlegde and famailiarity that you feel should dissuade me? I think my tone here sounds as though Im writing a legal breif, sorry if it comes off that way. just looking for advice on how to best go about it in my case. Thanks again.

[DonV]

Hey we have all been where you are at....shoot I'm still there!!!! I did an Arjay transom and am very happy with the results, I learned a lot of things I wish I knew before I started, however the end result was good. I did not go up to a 30" transom, just like you going from a 20 to a 25, and in hind site I wish I had done it. I guess because I'm a "cheap bastard" and prefer to do things myself I tackled it on my own. I learned a few things on the "not to do list" and as luck would have it, most turned out actually like it was supposed to. One thing I would have done differently was to make a grid of fiberglass re-bar, suspend it between the front and back transom skin and poured the Arjay over that, think of it as pouring concrete with re-bar and wire to add structure. Oh yeah, if you go with Arjay.....NO leaks, NO leaks.....ask me how I know. Good luck!!

[Rybones]

Thanks DonV, funny thing is, I had the"rebar" thoughts too but coosa not fiberglass although I wasnt actually planning on doing. Why were you thinking 30"? I had considered that also because I was considering going with the porta bracket (that is no longer the case) and 30" would still allow me full tilt with that bracket. Also Arjay is a very strong consideration. But again, please tell me your thought s on going 30" and your misgivings for not doing so..

[77SceptreOB]

Originally Posted by DonV

One thing I would have done differently was to make a grid of fiberglass re-bar, suspend it between the front and back transom skin and poured the Arjay over that, think of it as pouring concrete with re-bar and wire to add structure.

Why do you feel this is necessary to add fiberglass rebar? Is Arjay not structurally sufficient? Were you not happy with the rigidity of the transom? Would Arjay bond to the fiberglass rebar to make a composite? Or would it create a cold joint and weaken the homogenious Arjay pour? Very curious...because I'm leaning toward this method of rebuilding my transom and have heard you speak about the fiberglass rebar concept before but never really had a chance to discuss it thoroughly with you.

Thanks,

Jim