Using Seacast or similar with 5in" Tarnsom Increase
 

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

I used Arjay and raised the transom 6 inches

Easier than what I thought

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

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.

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.

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.....

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.

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!!

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..

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

First the 30" transom, it would get the top of the transom plus the splash well drains five inches higher and the engine power head that much higher out of the water. I've seen the 30" transom on quite a few and I iked it.

The fiberglass re-bar is just over kill, which I like, and thought it would be a nice addition. Rest assured the Arjay will stick to the re-bar. I don't put too much thought into such big words that start with homo. :) Above my pay scale.

My guess is peace of mind!;)

Please excuse me while I geek out here, just adding confusion of engineered structures without all the equations and tensile diagrams…
Rebar in concrete is for strength in tension because concrete is weak in tension but strong in compression. When it is in the middle of a concrete slab it really doesn’t help for flex. When a piece of concrete is designed for flex the rebar will be on the outer part, maybe an inch inside the concrete to protect it from the weather etc. That is why you see ‘cages’ of rebar in poured concrete columns.

A similar concept applies to reinforcing a pourable transom. The glass is there for tensile strength and should be on the outer edges; in the middle it just flexes. This is why a slab of Coosa just has a thin layer of glass embedded in both outer edges, not the middle (you can see it if you cut a piece).

A modern transom is cored construction with very high compressive strength (to keep bolts from crushing the core). The Elements of Boat Strength by Gerr has a very good discussion of cored construction – it is worth the read.

You can do what you want, but if I was doing this project I would lay up strong skins (scarfed to the old skins and finished smooth) around a temporary form of a core, pull the temp core and then pour Seacast in. A couple of additional layers of 1808 or 1708 could be added to the inside of the skins (covering the joint by about 3-4 inches) after the form was pulled. That way you would get a transom with construction similar to Coosa without having to completely remove one skin. Use peel ply on the layups. Since Seacrafts like the motor to run a bit high, I would make it either 26 or 31 inches, depending on what motor I was using.

Like others have said, practice on another part first; you don't want to realize you made a mistake by looking back at where the engine used to be. Good luck.

Rybones,

I went to from 24" to 30" on my Sceptre based on strong recommendations from Ken (Kmoose). I love it! Keeps the motor obviously higher out of the water and lets it keep breathing in reverse

Thanks All, now we are cooking with gas. Why do we want to lay up to the outside first/primarily and then to the inside? I figured there would be greater streanth (perhaps only maginaly) laying up the glass from the inside first. Also, I'm still trying to get my head around this 30" (or 31") inch transom thing. Wont 30" affect the overall ride greatly as I am currently at 20" and eleminating most ability to reverse? (I currently have a 25" shaft (insert joke here) and also have a hydraulic JackPlate with 5" of travel and 5.5" of setback). As it stands, my boat gets out of the hole instantly and I have a top-end of 45 plus it rides really nicely. I can see raising 5" or 6" but 30" or so is a 10" incrase that makes me think it will have a great affect on my hols-shot and ride. Please let me know the impact of going 30" and why, plus if it affects my rigging.

I would say its a viable option and would work if done right but me personally I wouldn't use it to raise a transom. I think what Flexpat says is the best word of advise. Long as you have the proper layups on each side you will be ok long as the core has the compressive strength for hardware. Make sure it is grafted to the old glass well. 12 to 1 and blend it in a ways with the inner and outer skins. I could see where this product would work well to fill voids vs cutting something open but I like the idea of wood or composite (dense enough) for transom cores. Especially if my motor is hanging off it or a bracket. There are a lot of loads from the outboard. Also just curious? What dose this stuff weigh? A 5 inch extension probably not so much but a full transom poured with this stuff would weigh a lot I would think.

Edit:
I really don't know much about these type of pourable products or have used them so I really shouldn't comment about them at all anyways. Those who have researched them and used it will tell you better than I. I would worry it could crack but with the technology today it may be a good product.

The 30" transom does not affect the hole shot at all. with my set up and tabs all the way down I am on a plane at 11 knots. A normal hole shot is very quick and clean. here are some pics of the finished transom, how it sits in the water and how it rides on a plane.

I looked in to the weight of seacast, it is lighter than pywood and a little heavier than Coosa. I dont know what the weight of Arjay or Nida is, but I assume it is comperable.

Eric B, that is a gorgeous Sceptre you have. A friend growing up had the same boat/color but his was an I/O. It rode very nicely and was a great fishing boat but a little on the slow side. It doesnt look like you have that problem. Although my 20 and your 23 have a similar hull design, the dimensions are very different. So transom height, ride and reversablity would also be very different, COG between those 2 boats is very different and you have a 300 hanging on there compared to my 2stroke 150. I have seen a 20 in the keys with a 300 on it. Wonder that thats like.

A 26" transom would be good for a 25" shaft mounted on the transom and a 31" transom would be good for a 30" shaft ; this is to get the AV plats somewhere between 1 and 2 inches above the bottom of the V. If you have a jack plate with 5" setback you could probably go a couple of inches above that.

Laying glass can really be done from either side - I would probably do it like I described because it seems easier for me to get a good finish - that said, I don't know your exact transom arrangement or skillset with fiberglass and resin. I consider myself to be a learner with a long way to go in that area. The big thing is to make sure the inside skin can handle a lot of tensile loads that come with an outboard hanging on it - especially with a jackplate which gives it a bigger lever.

Also - plywood weights: Okoume and Meranti (I think Lloyds certified too) are both pretty close to 26lbs/ft3 like Coosa Bluewater 26 and unspecified 'marine' plywood is more like 30-35 lbs/ft3.

What Flexpat says is correct. I've had no experience with the 20'ers, only the 23', and the inner skin was very thin, outer skin a different story, very thick. Remember I took off the outer skin on my transom. I would do as others suggest, lay a layer of 1708 on the inner skin, cover every hole, tuck the 1708 in in the corners. Arjay is bad ass stuff, however it will find any hole you have. The holes such as the "D" rings on the transom I just used a 2" x 2" duct tape on those.

Just for grins I looked at the price of the Arjay at FGCI in St. Pete yesterday while I was there, it was $180 for the 5 gallon pail, I have the catalog from 2009 and I paid just less than $120. Ouch!

Thanks for the answer on the transom hight Flexpat. I think I'll go the 26". As for the glass layup, I was talking about doing the from the inside-side of the of bothe the inside skin and also on the outside skin but your point on where it is easier to work on from and get the best finish. And yes, the jack plate definatly acts as a lever. It had a static JackPlate on it for 10 years that was fully lifted the entirre time to compensate for the 25" shaft. That is part of my concern and the reason for my expediencey to address this so that leverage doesnt lead to some catastrophic failure where I become reliant upon mermaids..

DonV, Thank you for the info on which cloth you think is best and well as your points about tucking it down in the corners. Good advice. As for the the price on the Arjay, its still less that the $233.50 per 5 that they are getting for Seacast. I'd be looking a 3 containers so that is a $150 difference. Does the Arjay have any fiber in it as the Seacast does? I like that aspect. And does anyone know how similar are these compunds to coosa board?

You want the feather/scarf at least 12-1. More is better here.
Are you going with poly, VE, or epoxy?

Both skins should be the same thickness/ schedule for optimum flexural strength.

Ask more questions plz.

Agreed on the do a hatch cover first for the rodeo learning curve.

I got ambitious and used a newer product for my teak dash frame.
I have used varnish a bit and researched the heck outta awl wood from awlgrip.

10 coats brushed on before blocking. 3 more before 3 coats of Upol UV bumper clear.
Looks amazing.

Hey GFS, got pics? I have not done wood finishing since my 1982 Whaler interior refurb back in ‘04. Two coats Mas epoxy with UV inhibitors. 12 coats Flagship Captains Spar. Almost all 5/4 Mahogany, looked better than factory because I duplicated interior but hid every single stainless steel fasteners from eyesight and weather. Wish I would have put it in my living room!

We need to split a room for Mother’s Day? HaHa

Vezo

Oiled teak is all I would consider on a deck unless it was a trailer queen used for joy riding to the sand bar. No hard finish I have seen would hold up to the rigors on a fishing boat. Once it’s finish is comprised to the wood it would pull in water and go dark. It would be higher maintenance than a Puerto Rican prom queen.

LMAO! How are ya? Yes it was a meticulously maintained ground up, over, inside, and new interior from wood I inherited from my Dads wood shop, back in ‘04. Could have been a yachts tender.

The teak deck in the Bertram actually was faux 4X8 sheets. He never sealed it I don’t believe. But here in SC it cut his ass. His girl finally would reach over transom into cock pit from swim platform, and “spill the cooler” before entering! Took top award for fiberglass at ACBY Mt. Dora two years in a row. THAT should have been the yacht tender!

GoFastSandman, I have a 3 hatches that I can and will do first. Epoxy and for the transom it was my understanding of 15 or even 20 to 1, for adhesion strenght. ANd will do on the skins being the same thickness.

Well one is very stiff and very expensive and needs lots of exterior fiberglass bonding, one is not as expensive and far from stiff....until it hardens.

I would go on their web site and send an email to the sales guys sales@arjaytech.com and get the technical data sheets on strength, compression, density, etc. I bought my Arjay in Sarasota, 8 five gallon pails because we did my brother's boat at the same time, and the guy had a sample about 12" square, 1 1/2" thick with 1708 on both sides as a display to mimic a transom. Then he hands me a hammer and tells me to give it a wack, not even a mark. I do remember the compression numbers and density were off the chart. Coosa Bluewater 26 is 26 pounds per cubic foot, duh, I think Arjay is very similar.

DonV, Did you use epoxy or poly with the two boats? And yes, I will call Arjay and speak with them before I do anything.

Epoxy will eventually yellow and fail.
Bitch to bring back down.

All my pics are on my I phone and PB.
PB wants clams.

I`ll shoot you pics.
Cheers,
GFS

Yeah, PhotoBucket is a scam. I have a bunch of pics of my kids being held for ransom. Who ever decided to do that to everyone is likely the child of a whore and a pedifile and should be shot on sight. I know these fourums are moderated so I didnt want to say what I really think. So you are saying Poly, GFS?

Epoxy, it's below the waterline.

There ya go, Bro! Baby steps. I really like like the idea of 26” or 31” heights! Do you have a buddy who will work with you? Many times I mixed resin, and even gel coat, one step ahead of the guy applying. It’s a friggin’ mess and will likely be a S#itShow the first three to five opening the containers... Buy 7 boxes of latex gloves, the Correct size!!! Actually that will be oversized because when you get good, you’ll be wearing two pair at a time!!!

Yeah, its just at the water line but I was hoping that I could use the poly so the gellcoat would come out nicely and last a while. ...

For epoxy you need nitrile gloves.
HF has 100 for about 10 clams.

A pro 3M respirator is also mandatory.
Not optional.
Epoxy is serious has mat.

Yes, I have a buddy with more experience than myself. And yes the 2x glove is a trick I use for food prep so it will apply here just the same. Not sure how much resin I should a gallon be plenty for skins for adding the 6" to the notch and closing up the top edge with the 6" tape?

FYI.....I think this is very similar to Arjay 6011, if not the same.

Pourable Transom Compound Carbon-Bond Formally Nida-Bond
CARBON-BOND POURABLE TRANSOM COMPOUND is ceramic filled
polyester exhibiting exceptional physical properties. In particular,
the compressive strength has been documented by an independent
testing laboratory to be 3,895 psi (ASTM 695). This is several times that
of plywood and 8 to 10 times that of PVC foam. In addition, the failure
mode shows elastic yielding before failure. This makes the CARBON-BOND
POURABLE TRANSOM COMPOUND material an excellent choice for
critical applications such as coring transoms on power boat hulls.

GreatYou chose wisely.

I've used this on my transom on the 20.. And the center keel...it is tough as nail... Maybe even tougher.. I layed up a skin on the inside and added foam tabs to tie the two skins together.. Pour small batches and watch for leaks.. Once you spot on seal it up best you can and wait for the excess resin to kick off.. I say small batches cause you don't want to loose the whole thing dealing with a leak..also small batches cause this stuff is heavy and dense.. It will want to try to push your skins apart..

Easy to use but it does take a lot of forward thinking... Ceramic beads are not nice on your equipment... I don't know why they used that stuff..put foam blocks in the places where thru hulls are going . Cleats , lifting rings, and ect.. It's easier to drill thru foam and glass than glass and ceram pour..trust me I know .. I sold boat after trying Good luck