New Transom Using Seacast
 

A new transom for CJ ...
Skip and I have just replaced our original wood transom on our 1966 Bowrider with Seacast.
I thought I would share our findings, experiences and process, in case anyone is considering a new transom for their boat.

We chose a pour-material because 1) cutting from the inside would have entailed too much work cutting and re-attaching the engine well and 2) really didn’t want to cut the outside skin either.

In summary, Seacast is a pour-able substance with fiberglass strands. It is heavier than CoosaBoard, but lighter than plywood with multiple FG layers. It is strong, drillable, tap-able, will never rot, and floats. For more detail & specs, check out their website.

Approx 3-4 days
Step 1, removed all hardware, then removed the cap to the transom with drummel tool
Step 2, tried to use long drill & drill holes in the wood from the top. Too solid, so step 3.
Step 3, used a chainsaw & cut wood out, used long-handled chisel to finish cleaning inside skins. All wood must be removed.

Approx 1 full day
Step 4, prepped transom, putting tape over holes, putting plastic on everything else we didn’t want slopped with the Seacast. I used masking tape for the plastic … should have used duck tape around the edges of the pour area. The masking tape just broke before it lifted off the overflow of Seacast. Also made drain hole plugs wrapped with saran wrap to keep Seacast from filling the hole.
Step 5, bracing the transom to maintain its shape. Added Seacast spacers between skins. Used the 4 engine bolts and 2-2x4’s to brace the outside of the transom. Used scrap plywood & 2x4s to brace inner skin too.
Step 6, make funnel to pour the very thick (like chunky oatmeal) into the 1.5” transom opening.

1 day with a 3 hour break
Step 7, mix and pour 5 gals, then mix & pour another 5 gals. Max 10 gals per pour, then must let it cure, and it does get hot. After 3 hours, it had cooled down and we were able to finish the last 3 gals of pour. As it’s poured, hammering on the transom with a rubber mallet releases air bubbles.

Step 8, cleanup of tools, easier once cured.

Step 9 will be to add an additional 2 layers of 1708 on the transom and over the transom cap. Then fair, sand, fair, sand and add some primer & paint. Then she’ll be done & better than new!

Thus far, we have been very pleased with the results and the support team at Seacast in answering all questions.

Overall, less than a week … not bad.
Here are the pictures .... !!!

"1 day with a 3 hour break"

I sure enjoyed the beer you offered and the fine company, during the "3 hour break"!!!! It's all in the timing, I show up while they are taking a break between the first and the last pour and enjoy a Corona!! Life is good!

You guys did a great job, you should feel quite proud!!!

Excellent timing Don - great post though, very detailed

NICE job Carla, and done on schedule too! I like Skip's plywood funnel! How come you sanded the paint off the transom? I'm guessing that where you're adding the extra glass? Using epoxy or vinylester for that? Jeff said that styrene will continue to escape from the Seacast for some time, so best to use poly or vinylester to avoid bonding problems between it and the glass. Denny

A nice matrix.

Nicely done as always,
Us

As a friend of mine used to say " well planed and well executed = a job well done"


Now... if you could get working that fast on the 21 you'd be done in a few years :D

"Now... if you could get working that fast on the 21 you'd be done in a few years"

Hummmmm.........you know Skip and Carla, he makes a good point!! :) :)

Thanks for all the possitive comments and encouragement.
Don, it was good to see you too and you're timing was perfect ... 1 beer & no work... we'll catch you next time... we have the 21 yet to do!

I wish we could move as fast on the 21 ... a bigger project and a bigger learning curve.

Denny, we are doing research on the bonding issue. We are epoxy people and that's what we want to use to wrap the transom & cap, leading into the engine well for securing it all very well. The exposed Seacast is small and may not be an issue. Running tests with epoxy soaked 1708 on a Seacast sample today ... let cure, then try to pull apart.
Hands on is the best educator.

Nice job!

How did you ensure the cavity was clean prior to the pour? One of the big concerns I would have is contanimation due to bar oil coming off of the chain.

Wow. What a creative solution to a common problem! I love the mental image of going at it with a chain saw.

Thanks for sharing, and let's hear how you finish it out. Makes me want to do another SC... well almost.

Great idea Carla! A pound of test data is worth TONS of theory! That's what always impressed me about Dan's approach to repairs! Denny

Looking good, Skip and Carla. You'll have her back in the water in no time.

Dave

Hi Carla and Skip,

Looks great, can't wait to see the finished work. Nice work Don, impeccable timing.:D

Better than new, huh? Did you discuss the Seacast product with Mr Moesly and if so what were his thoughts on the product? I am considering the Seacast product in the Seafari for same reasons and have only read positive feedback on Seacast.

Couple of questions - how big were the chainsaw and the chisel. Got pics?

Thanks for the encouragements.

GW204 - The president of Seacast suggested spraying inside the transom with iso-alcohol to dry the wood out to make it easier to removed with home chisel. The oil was easily cleaned with acetone.

McGili - The chainsaw I used was electric & had a 16" chain. Seacast & others suggested drilling holes with a wood bit or auger, but because of the wetness, it was very, very slow. So I sharpened the chainsaw & sent to town. After a short period, you develop a rhythm. My homemade chisel was made from a #5 rebar, 40" long, ground approx to center of rebar & approx 4" long. Opposite side was beveled for the point.

I presume thats how you got the bittom part of the wood - as a 20" transom and 16" saw wouldn't get it. My friend Mike used the chain saw trick also. Do you then have to kinda push the Seacast into the corners?

Thanks for the pics, Skippertee. I was wondering how I might circumvent buying a 40" chisel. Once again simple workbench fabrication saves the day (and the wallet) ! Nice job.:cool:

Nicely thought out SkipperT and friends.

Cheers,
GFS

Janet is getting sick of Cobia. Mmm Cobia. Bugz?

Just wondering how a styrene blush (very slow and tiny amount) could effect the epoxy bond (fairly quick 95% cure)? If you've properly cleaned and prepped the Seacast surface prior to applying the epoxy, how much of anything is going to blush out in the next 4 hours?

Mr Moesly was impressed with the these new products, he they were out when he was building. Dog, we just juted the seacast and it pretty well moved into the corners and around the spacers. fg1, I noticed a very blush. I put the caps back on, so there is little seacast exposed, but washed areas and have wiped transom with interlux 202 and acetone.

Would Seacast be suitable for a larger boat / transom such as a 23'? We are talking about a larger transom and possibly twin engines up to 450 hp. Opinions?

In our research we found nothing to restrict the size of the transom. I understand that 23 and 25 foot boats have been done.

I measured mine into the corners and down to the bottom of the center - 20" - would I just dig out the rest with the chisel??

Yep ... Then use a shop vac to suck up the pieces.

Hey Dixon......the more rotten the wood the easier to remove!!! I poured my transom and it's ALL in the preperation, the pouring is easy. :)

There is a local guide in my area who rebuilt his 22 Mako and used Seacast for the transom. He did a great job documenting the entire project including video. Here is the link to the page with a couple of videos hogging out the transom.

Enjoy!
http://skimmer.smugmug.com/Boat-Main...33412_RB3Zrz/4

http://skimmer.smugmug.com/Boat-Main...33412_RB3Zrz/5

Is there any way to funnel that stuff to the bottom to kind of 'bottom fill' it maybe take care of some of the air bubbles? Thinking that might be the route on my Cruisers?

Can seacast be used to redo a 20" transom and raise it to 25" ? Will the styrene blush cause bonding issues in the exposed 5" of seacast resulting from raising the transom ?

Take a look at the links above. Before they poured the transom they created a mold for a modified notch. I guess they figured it would be safer if they raised the surrounding area to let in less water.