Transom replacement-Turned Complete Boat Rebuild

[HVAC Cruiser]

I am new to this site, although most of my help on my project was from threads from this site. I have I recently started rebuilding a 1973 21 ft Cruiser. The transom was rotted so I cut it out and made a new one out of 2 3/4" Coosa composites Bluewater 26 laminating them using the west system and matting. My question is, when installing it I had planned on using a combination of woven roven and mat for the build-up. am I right with using the woven roven it seems to be stronger from what I have read. Any input would be great, this is my first rebuild and I want it to be right.

 

[Rickairmedic]

Re: Transom replacement questions

Re: Transom replacement questions

Cruiser I cant help you with your question as I am a Tin Can boater but I wanted to welcome another HVAC guy to iboats and will bump your post so one of the Glass guru's spots it .



Rick

 

[HVAC Cruiser]

Re: Transom replacement questions

Re: Transom replacement questions

Cruiser I cant help you with your question as I am a Tin Can boater but I wanted to welcome another HVAC guy to iboats and will bump your post so one of the Glass guru's spots it .



Rick

Thanks for the welcome, and the help with getting the post spotted. This is all new to me and I want to get it right the fist time

 

[HVAC Cruiser]

Re: Transom replacement Fiberglass questions

Re: Transom replacement Fiberglass questions

I took some pictures of the project thought they might explain it better


Thanks in advance
Bill

http://s785.photobucket.com/albums/yy135/hvacbill/Boat Project/

 

[VeroWing]

Re: Transom replacement Fiberglass questions

Re: Transom replacement Fiberglass questions

I just completed a complete transom rebuild on my 22' Grady. I found site in link below very helpful as far as which materials were recommended for different types of repairs and boatbuilding. They also have a forum with plenty of knowlegeable people that will give you good advice.

 

[HVAC Cruiser]

Re: Transom replacement Fiberglass questions

Re: Transom replacement Fiberglass questions

I just completed a complete transom rebuild on my 22' Grady. I found site in link below very helpful as far as which materials were recommended for different types of repairs and boatbuilding. They also have a forum with plenty of knowlegeable people that will give you good advice.

Thanks for the heads up, I looked at the site they say to use biaxial 1708, after a little more research product descriptions say biaxial is stiffer, guess its no woven roven on the transom
Thanks for your help
Bill

 

[metriccrescentwrench]

Re: Transom replacement Fiberglass questions

Re: Transom replacement Fiberglass questions

I just finished transom/stringer/deck replacement surgery on a boat a few weeks ago, I used one ply of 1708 biax on the forward face of the transom. (You really don't need to add anything to the rear of the transom because it'll be securely bonded to the existing skin which is already plenty strong.) I'm currently working on a '79 Checkmate and will use 2 plies of 1708 on this one because it's a much higher performance boat and I just want to be ultra sure of it's strength. I buy 1708 fabric (along with most everything else fiberglass related) from US Composites ( www.uscomposites.com )

 

[berry79]

Re: Transom replacement Fiberglass questions

Re: Transom replacement Fiberglass questions

(You really don't need to add anything to the rear of the transom because it'll be securely bonded to the existing skin which is already plenty strong.) ( www.uscomposites.com )

By looking at his pics you see he removed the outer skin. If it were me I would build it back up with at least 4 layers of 1708 and a final 2 layers of 1.5oz CSM. But I'm fairly new to boat restoring so maybe others might have a better idea.

 

[HVAC Cruiser]

Re: Transom replacement Fiberglass questions

Re: Transom replacement Fiberglass questions

By looking at his pics you see he removed the outer skin. If it were me I would build it back up with at least 4 layers of 1708 and a final 2 layers of 1.5oz CSM. But I'm fairly new to boat restoring so maybe others might have a better idea.

Thanks for the input,

thats what I was thinking 4 to 6, I just started doing the buildup 2 layers on the exterior are now done. making sure I am wrapping it the sides of the boat. I plan on checking the thickness after the 4th. this has turned into more of a project, looks like im tearing off the deck. I actually have that on another thread if I had realized it I would have combined it all onto one thread.

http://forums.iboats.com/showthread.php?t=352695

here is a pick of the starting of the transom install

Bill

 

[berry79]

Re: Transom replacement Fiberglass questions

Re: Transom replacement Fiberglass questions

When you wrap the layers around the side and bottom, make sure you overlap each new layer a few inches past the previous.

 

[HVAC Cruiser]

Re: Transom replacement Fiberglass questions

Re: Transom replacement Fiberglass questions

When you wrap the layers around the side and bottom, make sure you overlap each new layer a few inches past the previous.

I was starting to do that with the first layer about 6" around the sides and bottom I figured I would end with the last layer about 12-14" up the sides and bottom, then I read this old post

http://forums.iboats.com/showthread.php?t=63674

it says to do it the other way around, starting long and ending short to evenly distribute the loads. I checked the reference they referred to, the west system boat repair manual and it says the same as the post
I am working on it today, I figured I would sand the layer I already did, cut my next layer to be the longest one and work backwards from there

Bill

 

[VeroWing]

Re: Transom replacement Fiberglass questions

Re: Transom replacement Fiberglass questions

Just a "heads-up" for you, that you may already know. Be sure to round off inside corners with a resin/fiberglass flour paste, and round off outside corners with router/trimmer also, before applying fiberglass material. Fiberglass will not bond well to inside/outside squared corners.
Also, regarding the layering of fiberglass to sides and bottom of existing hull, link below shows that layering should INCREASE with each layer, as opposed to decreasing. I'm no expert, but the author of article in this link was head architect/designer for Pursuit Boats thru-out the 90s. Article also shows transom replacement from outside like yours.



Be sure to click "next" at bottom of link page to go to further pages. Mike

 

[HVAC Cruiser]

Re: Transom replacement Fiberglass questions

Re: Transom replacement Fiberglass questions

Just a "heads-up" for you, that you may already know. Be sure to round off inside corners with a resin/fiberglass flour paste, and round off outside corners with router/trimmer also, before applying fiberglass material. Fiberglass will not bond well to inside/outside squared corners.
Also, regarding the layering of fiberglass to sides and bottom of existing hull, link below shows that layering should INCREASE with each layer, as opposed to decreasing. I'm no expert, but the author of article in this link was head architect/designer for Pursuit Boats thru-out the 90s. Article also shows transom replacement from outside like yours.

http://boatbuildercentral.com/howto/aquasport/index.php

Be sure to click "next" at bottom of link page to go to further pages. Mike

I did not know about rounding the corners of the transom but god must be on my side cause I had to round the corners to match the corners of the boat on the outside.

when I initally set the reansom in place i wet the channel at the bottom and sides, laid in Mat,wet it again, then made a thickend epoxy for a bedding laid it in the transom. I had 2 of my workers help me and we pressed it down so some squished out. I then used a jointer to make a compresed bevel where it meets the boat. Hopfully its ok the way I did it

as luck would have it after reading what berry79 said about the layers, when I got to the shop this morning, I looked the boat over measured things up ran a load and stress simulation, it showed there was no difference in which the layering went. So, to make it easier for final finishing, I laid up 4 more layers of 1708 ( I already had 2 ) then finished the layering off with 2 layers of CSM Increasing as I went. my final layer is about 1' forward of the transom.
I used the west system epoxy with the slow cure hardener.

 

[HVAC Cruiser]

Re: Transom replacement Fiberglass questions

Re: Transom replacement Fiberglass questions

Quick update, Transom in and Faired

Next onto replacing the deck and stringers

 

[Rickairmedic]

Re: Transom replacement

Re: Transom replacement

Cruiser I am glad to see the Glass guys showed up . Your transom is looking good . I still have to do the transom in my Tincan but it is sooooooooooooo much easier in a tincan than in a glass boat .


Rick

 

[chrishayes]

Re: Transom replacement

Re: Transom replacement

I found the same thing during my research regarding the overlap techniques. West system does show it going from first layer long then shorter each subsequent layer This truly just doesnt make sense...If you go short first then longer you are getting the same bond to the piece before PLUS another bond with the existing hull material. That just seems better to me. If ondarvr jumps in on this thread I would like to know what he thinks as he is basically all of us fiberglass guys wise uncle Nice job though regarless, looks good from my house!

 

[VeroWing]

Re: Transom replacement

Re: Transom replacement

Looking good!

 

[berry79]

Re: Transom replacement

Re: Transom replacement

Looks good HVAC Iknow that coosa was expensive, but this will be the first and last time you will have to do it on this boat.

 

[HVAC Cruiser]

Re: Transom replacement

Re: Transom replacement

Glad to hear everyone likes the way it came out I can't thank everyone enough for their input, couldn't have done it without it. This was a first for me
Your right Berry79 it was alot more but after research I figured it was the best for the application, guess thats why they call me "Overkill Bill" LOL

Now for my next delema, I found my floatation foam water logged and some below deck rot, (when I stepped on the platform for the fuel tank my foot went right through it and im only 135 lbs. I tore off the deck today, the stringers are pretty good, damp but not really much rot. There are a few spots were screws were and such that had a little but all and all there is less than 5% rotted. the deck support and areas around the bait wells are another story. all the supports are completly rotted out.

Here is my question if anyone can help, I can't find marine grade plywood locally, can a use ABX or BCX and just soak it with thinned epoxy first to seal it before glassing.

 

[berry79]

Re: Transom replacement

Re: Transom replacement

I've read plenty of post were people have used A grade exterior plywood. I don't think you need to thin the epoxy when you coat the plywood. I believe a slow cure will be sufficient. Then again I'm not 100% sure, since I'm using poly. I'm sure someone with epoxy experience will help answer that part of your question. Keep up the good work.