1980s Coastworker 180 transom core replacement questions/advice sought

[CW180]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Thanks for the detailed reply Bill - appreciate it.

Will respond on the other thread though. Apologies for the confusion!
I thought it would be better in retrospect if I raised a separate thread for the cap removal so the thread title might garner more specific response.

 

[Bondo]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

CW180,.... A new thread isn't needed,... yer info 'n pictures are Here, not there...

I edited yer post, #19, 'n I'm gonna delete yer other thread... (Sorry Bill, you'll loose 1 post count)

CW, You've got a Great thread runnin' here, with Great advise, 'n graphics posted....
It'll be a Big Plus for the archives, for Years after yer done, 'n gone....

Go with it, Here,... Don't break up the Info....

Btw,... The pictures in yer other thread were pretty mute, 'n don't show the here, 'n Now angle,...
You'd been better off to just link This thread to it in yer post, than adding all the Before pictures....

Carry on Gentlemen,...

 

[CW180]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Fair enough - sorry for causing confusion!

Boy am I glad I pressing CTRL-A, CTRL-C before I clicked on submit for the following reply on the other thread I'd started!!

Thanks Bill for the reply here..

Sorry, when I mentioned Nidastuff, I meant their equivalent to seacast rather than the composite sheets or what have you. Perhaps it's Nidabond or something like that. Its more or less the same sort of thing as seacast from what I gather anyway. Apologies if you are actually talking about the same thing and knew what I meant!
Either way, neither of these very handy products appear to be available to us here in the UK which is a real shame. Those companies are probably missing out on a handy extra amount of sales as a result.

Maybe I should ask them if they want franchises in the UK!

Anyway.

The bond of cap to hull is a bit of a worry following your comments on the other thread. I'm panicking a bit about what will now need doing to get a decent end job. That being said, I was worried about de-capping the transom and cutting into it but it wasn't that bad. I was worried about


Do I take it from that, that there's no 'reasonable' or practical way to remove the cap without more or less destroying the boat?!

If not, that's something I'm somewhat gutted to hear now that I've removed the strips from the outside and drilled out about a million rivets this afternoon. Is there a crying smiley I can insert here?

It's actually refreshing to hear the comments you made about the outer transom skin I must admit:

In Florida anyway, and at yards who make a living doing transom rebuilds, it's very normal to cut the outer skin off, insert the new transom from the back and glass the skin back on...without wrapping glass around the corners. Cosmetically it looks no different than before cutting. The exterior transom skin typically add very little structural value to the transom core anyway

The other day I decided that for numerous reasons the only way I could carry on getting the transom sorted was by cutting out the outer skin and removing the wood that way. I was going to post up a really long detailed and reasoned post about why that was the case etc (I'm an analyst by profession, and that's because it's something I do in pretty much all aspects of my life, that I analyse things a lot before reaching decisions), but I reached the conclusion that an outside cut is something that some people are vehemently against and decided better to just get on with it rather than go into it here.

Even though I know for sure some people will disgree and tell me I'm foolish for doing this, I'm not sorry I did it because it has given me unparalleled access to what's going on in there, and after a lot of research have learned that if epoxy is used when repairing the 'scar' with the glass concerned it's allegedly stronger than factory polyester so the outer skin is not structurally compromised if done right.

As you mention in some cases cutting the outer skin seems to be the norm and I've found that on at least a couple of repair shops. Presumably they have to be accountable for their work and know what they're doing. I've found tons of documented accounts of being doing very successful looking outside cuts, but yet to find an account of one of those leading subsequently to some sort of catastrophic structural failure, or even anything close, so at that point I made the reasoned decision to proceed that way.

Cosmetically? Well, yes I'd freely admit that it can lead to a lot of effort and time making sure the transom looks as smooth and pretty as it did beforehand, but cosmetics is less important to me than others traditionally, so we'll see about that. As long as it's strong and basically safe then I'm happy, and making it look nice is a secondary concern.

It's done now anyway and was very easy and quick compared to what had been a big struggle the way I was doing for a few reasons. The outer skin is in one piece following removal, which I did 4" in from the edges of the transom, in order to enable plenty of strong border around the new core, and for faring in the scar etc.

Having removed the outer skin, it was what I found beneath that concerned me more, and made me decide to remove the cap.

Here's the overall view from the rear now. Scary!

There's a bilge section beneath a deck hatch that unscrews, and even though this appears to have no access from other areas beneath the deck, it had a lot of water in it. I drained most of it, then noticed a crack here (approx horizontally across the pic):

And here on the other side of this stringer or transom knee, whatever you call it:

Here is the built in sub deck bouyancy. Lots of gallon size tubs like this:

So. At the moment I really would like to remove the cap to sort out every possible evil that might lurk beneath. Part of the reason also is that some areas of the deck when walking on it feel solid, but other parts have 'give', which makes me thing the bond between deck and sub deck areas has come undone in places. Possible it's just where I'm standing might be between deck support areas, but since I've seen cracks elsewhere, it makes me thing pessimistically.

I guess if I have to then I can do just what you described, which is to cut access holes in through the deck so I can inspect and repair any issues beneath the deck, but given a choice and given I've gone this far with the butchery I've already done, I'd now be a lot happier if I could remove the cap to ensure I can get to everything and do the best job possible.

Phew! That's a post and a half!

 

[Woodonglass]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Soo you cut out the stern of your boat, against the advice of the PRO's here on the forum, and compromised the hulls integrity, and now you want to do it the right way and remove the inner tub???? It's your boat and you can do what you want, but you have just complicated the process to a level that will be more labor and cost intensive. Hopefully the PRO's will be able to guide you through this and your skills will be up to the challenge. Most of the time the easy way turns out to be the least desirable method.

 

[CW180]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Yes, that's what I did. The hull's integrity is already compromised regardless of me doing this, especially given the additional issues I have consequently discovered, and I intend to rectify both aspects of that problem fully, and to the point where it is stronger than it was from the builders since I can spend as much time as I wish ensuring that is the case. I can afford to buy resin and fibreglass product as & when required, and since the boat barely cost me anything, the cost of materials to restore will still amount to a very cheap but very strong craft once done.

It would be futile and silly of me to try and pretend that I know better than you guys in respect of construction as I do not have the same experience, and I wouldn't for a second suggest that I do, but based on what was unfolding while attacking the core from above I determined it as the best thing to do under the circumstances.

If nothing else, I would not have been able to to repair successfully the bond between the inner skin and the hidden partition that was inside the transom from above due to lack of access, and had I removed the inner skin, I would have had trouble still because I never would have been able to secure a decent bond between said partition and the inner skin as it was originally bonded against.

It's difficult for me to explain this satisfactorily for you to picture what I'm describing, but rest assured that I did not make the decision lightly, and without a great deal of consideration. I don't expect you to agree, and I largely understand why, but now it is done only have the option of moving forwards. This boat stands me at a cost of ?300, which I could get more than from selling the trailer if it came to that, so should I fail for some reason to carry out more than adequate quality work I'm just back to where I started a couple of months
ago, and not really any worse off.

I don't for a second believe that will happen however, and have every confidence that while it will undoubtedly take time, effort and expense, I'll have an excellent boat at the end of it that I know I can rely on, contrary to the weakened/damaged vessel it transpired that I had bought.

Suffice it to say that regardless of whether I heed specific bits of advice and knowledge given, I DO appreciate such comments being given, in order that I can make a suitably informed decision. Please do not take it that I am "dismissive", or indifferent to your suggestions (or those of others) on the grounds that I haven't followed them. Like I say, I appreciate and understand the input regardless.

As I explained above, I knew full well that when doing this some of you guys would not agree with my rationale for doing so, but it's difficult for you to see quite what I was going to have to deal with without cutting the exterior, despite the fact I know that you've experience of other cases of this kind of thing from your comments.

As Bill has described, and as backed up by many people (PROs included) on other boat sites, including repair shop websites I've seen, there should not be a structural issue from cutting the outer skin if it is repaired correctly, and it is a commonly applied approach. I have no reason to doubt this, and to reiterate, despite finding countless accounts of people cutting the outer skin, have yet to find accounts of this leading to major issues. I'm not suggesting that problems don't happen, but am suggesting that as mentioned, if care is taken that it should not be an issue in terms of hull strength or safety.

Hopefully in due course as work progresses I'll be able to demonstrate that I can indeed to a suitable job in respect of ending up with a strong boat that I can depend on for many years to come.

Edited to add, that if any of this post comes across in any sort of negative way, it is most certainly not intended, and I'm purely trying to assert comments explaining my choices.

 

[BillP]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Hey Cw180,

Just what you needed, a lecture. Don't sweat the put down. Go forward and dismiss it...but first, ask how many transoms, stingers and floors that poster has personally replaced.

bp

 

[CW180]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Appreciate the moral support Bill but that's not something I really want to get into.

I've run a car forum myself for about 8 years now, and if there's a couple of things I've learned, it's that:
1) There will always be strong differences of opinion on how certain tasks should/shouldn't be done especially where either way generally can be demonstrated to give the required result (eg people argue about the best way to remove engines - whether the gearbox should be separated, and engine out of the top, or beneath the car etc).
2) If a newbie starts questioning the comments of posters that are very very well established they can quickly get themselves disliked in a forum community. I'm not about to go there.

So I'm taking comments in the spirit which I am sure they are intended, i.e. well.

The deed on the boat is done now, and I believe is right for what I need to do, and I have a very set way in my mind of dealing with the transom repair.

The bit that I am less certain of was the bits below deck, but your suggestion of cutting access holes in the deck can address this.
I wish I had an exact map of where the deck is supported though so I can cut accordingly.

Re' the cap, if nothing else, trying to remove it, only to find that the cap is very firmly bonded to the rest of the boat under the deck gives me reassurance about what I thought was a bit of softness. I guess it was just areas between supports.


Oops mentioned that regardless of how I choose to proceed people would offer support and advice, and I'm hoping that holds true despite the fact I have gone against certain advice.

Like I say, I appreciate and respect the advice given even if I don't decide to always follow it.

Jim

 

[CW180]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

One thing I need to ask actually, is when repairing a cut between two glassed panels, and feathering the join for strength, is it the norm to use the same technique for basic layering up, ie to use first a layer of CSM, then a layer of roving, and repeat alternately to the required thickness?

Also, my friend who is quite well up on his fibreglass stuff mentioned that for epoxy if I was going to use it, I need to get a different kind of matting/roving, that does not have styrene in it I think? He said that the styrene is there for the polyester resin to effectively melt, whereas this is not necessary with epoxy and might reduce the strength if it's present in the matting/roving when it doesn't need to be?

I've got some supplies of roving and matting but they're either 300 or 450 weight so I'm not sure if they're the best thing for this kind of work?

Thanks!

 

[Woodonglass]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

If you want to re-Gelcoat the transom, just remember, Gelcoat does not readily adhere to Epoxy. MFG's will say that it will, however most of the PRO's on this forum, will tell you that it's not recommended. The new Biaxial Cloths are much stronger and easier to use than the Woven Roving. I'd recommend you investigate using them. Also when using Epoxy, CSM is not required. Some people say you can use it, while others say it's a waste of Epoxy, since epoxy has no Styrene thus the CSM does not break down. Basically acts as Cloth and CSM will not add any significant strength due to the way the Strands are loosely configured. That's JMHO given from what I have gleaned from the PRO's here on the forum and heavy research on the topic, so take it as you will. The interior tabbing of the transom to the hull is where, most of our experts will tell you, the structural integrity comes from when installing a transom. I'm struggling to detrmine how you will be able to accomplish these tabbings without cutting back the interior tub walls to gain access to the hull sides. OOP's described this in his former posting. As you say, it is your boat and you are free to do with it as you see fit. If my previous post offended you in any way, I am sorry for that. Not my intention. I was just shocked to see the outer skin removed. Others that I have seen do this were less than pleased with the results. You hopefully will have much better results. I'm sure of one thing, you are on the RIGHT forum to get the needed advice for your project.

 

[CW180]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

No apology needed chief, and no offence taken - I hope my post didn't come across at all over defensive either. I do tend to rattle away at the keyboard adding a lot of potentially waffly content when I think I need to describe something at times.

You'll have to excuse my lack of knowledge on the correct terminology here, but I'm not quite sure what you mean by the tabbing of the transom. Could you elaborate a little on exactly which parts that consists of for me? Sorry to be ignorant of the term.

Interesting point about the gel coat as that's one thing I hadn't heard before I must confess. Would it be reasonable then after prepping the transom, to mix the pigment with some thinned epoxy and spray it on to achieve a smart finish? I don't have to use either the gelcoat or the pigment but I'd bought it a while back for doing minor cosmetic repairs and thought it might be ideal for covering up the scar once the structural stuff is done.

I had read a week or two back about not needing the same layup layering for epoxy as for poly, but with the amount of stuff I've been reading about all this lately I'd clean forgotten that, so thanks for the reminder!

Reason I was going to use epoxy for repairing the scar is that it's stronger, and I already have a load to hand so it would seem to make sense to take advantage of that.

 

[ondarvr]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

The transom can be done from either side, the reason most people say to do it from the inside is the exact same reason you are planning to remove the cap now, more needs to be done than just the transom, so the inside needs to be gutted too. Most boats have wood stringers, so if the transom is rotten the stringers are typically in the same condition. In this situation it’s easier to do it from the inside and avoid the cosmetic repairs needed when doing it from the outside. If a boat yard or glass shop is told to only replace the transom, then many would rather do it from the outside and avoid the possible issues of getting the boat apart and putting it back together, it takes more man hours to remove the cap. It may not be fixed correctly because there is rot elsewhere, but they are doing the work they're getting paid for and that's what they're concerned about. Some hulls also have fiberglass stringers (no wood), so if you know this ahead of time removing the cap may not be needed.

It looks like you left a good sized lip on the outside of the transom, so you can glass to it and not need to wrap it around onto the hull, so you’re OK there.

You can use epoxy or polyester, either will work, like others said, gel coat doesn't bond that well to epoxy, so you should paint the transom if you use epoxy. Epoxy has poor UV resistance and adding pigment doesn’t help a great deal.

Polyester needs mat, epoxy doesn’t. Since epoxy doesn’t need mat, and is stronger, you can make the repair thinner and lighter, plus still have it strong enough to do the job. In many situations the difference in weight isn’t going to make much of a difference and neither does the thickness of the laminate. The difference in weight may only be the a few pounds at most, so use what you feel comfortable with.

 

[Woodonglass]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Tabbing is basically running the Glass Mat and or Cloth onto the sides of the hull in order to tie the transom and sides together and increase strength. This drawing will help you understand I hope.
ondarvr is one of many forum experts on Fiberglass and Gelcoat. He indicated that your Transom "Lips" are large enough that whey you glass the wood transom piece back in you'll be able to run the layer of glass onto them and to the edge of the existing outer skin and have suffiecient contact area to make the installation strong and secure. That's a very good thing. I would recommend attempting to tab on the inside as best you can. There appears to be some room along the sides between the tub and the hull wher you might be able to get some tabbing in there. You are right about epoxy being stronger but your boat is made from Poly and IMHO the poly will be more than strong enough for your needs. But as he stated, You could use the epoxy and just paint the transom. Totally your call.

 

[CW180]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Very helpful posts from you both, thanks.

Ondarvr - yes i deliberately left a 4" edge around the cut so that there would be ample space to feather the join over a bigger area than I thought would be necessary, in order to be confident I would have no issues at all in terms of the integrity of the skin once repaired.

Stringers in my boat are glassed in foam, and it appears to be in good shape thankfully. This is a bit of a relief since it appears I cannot remove the cap anyway. I've got a shedload of riveting to do now I guess, but at least I know the bond between cap and below is very solid indeed as I could barely lift the edges of the cap once released as the bond was so good. It's reassuring.

I'm not really concerned about weight saving on this boat as long as I'm not adding loads on what was originally there. The boat weighs between 350-400kg and will have a 75 on the back so will be plenty quick for me when I want it to be. No real benefit in me saving a few lbs when I'd prefer extra strength and peace of mind for safety. If I'm gonna save weight anywhere, it ought to be from myself first!


Woodonglass - thanks for the explanation.

You'll probably be shocked to hear this but there actually isn't any real tabbing as you describe it and show on your diagram.
I've just been outside and inspected inside the open cut and there's basically a single layer of thin CSM from the transom core to the inside surface of the outer hull. That's literally all!!

So I'm sure that one way or another I can improve on that and put this back together a lot better than it originally was.
Once I finish excavating the last bits of core, I'll have good access to prep the inside surface where that is, and when rebuilding, I may make a smallish holes each side on the inside skin so I can reach in and add some security in there. It's likely that if I'm going to do that I would actually glass a vertical support into the inside of the 90degree corner of the core and hull. That alone would be way stronger than what the manufacturer put there.

Thanks again for the info chaps.

Jim

 

[Woodonglass]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Yes, I know, The factory typically does not do the tabbing. During the restore process most of us recommend this to ensure that it's "Better than Factory" Here's a pic of a well done Restored Transom. You can clearly see how he has wrapped the glass to about a foot onto the sides of the hull as well as the bottome of the hull.

 

[CW180]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Ahhh - misunderstood sorry.

Thought you meant that I wouldn't be able to recreate the original tabbing that it would be likely to have had in place.

So effectively worst case in respect of tabbing is that it goes back together with the same strength that it had from the factory, and in all fairness to the boat/builder it's lasted pretty well for something like 25 years with only some minor cracks in one or two places, and a wet transom core on account of some berk drilling holes through for an aux motor bracket.

I reckon I can do it better than this though without too much difficulty!

 

[Woodonglass]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Yep, I bet you can. Having cut out the skin, If it were me, I'd try hard to get the Exterior and Interior tabbing/glassing done as best I could to ensure I had the required strength in the structure. How large of a motor are you anticipating putting on her?

 

[CW180]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

It's a 75 that is going on her. Transom was rated to 125hp originally, so I'm using way less than the max, not much more than half in fact.
That, combined with additional strength will mean it should be good for approximately forever.

The magazine review I have a copy of (can't post up sadly due to copyright sorry) states that with a 40hp and 2 people the boat was good for 22knots/25mph, so with nearly double, she should shift pleasingly, but still tons below the limit for the original construction.

So all things considered I think she'll be in a happy place once fixed up.

 

[Woodonglass]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Yep, that is NOT going to be a problem for that boat. I think when you're done, She'll be a Sound and Solid craft. Keep us posted of your progress and any other issues that you feel we can assist with.

 

[CW180]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

I certainly will, thanks.

I'm first going to patch any areas where I can find cracks or bits that look inadequate to me, then I will move on to other areas.
I'm tempted to practise my glassing technique a little by trying to make a splashwell first before doing structural work like the transom.

Could do with having some thin ply for that though or something like that.

 

[CW180]

Re: 1980s Coastworker 180 transom core replacement questions/advice sought

Right - time for a destruction update!

Well, I got every last scrap of wood out of the transom after spending some time with the chisel recently.
I discovered something that disturbed me further though after gaining access from the back to see down the void between inner and outer hull skins.

Looking inside I saw that one of the parts of the bracing running across the hull, beneath the deck was beginning to separate from the bottom of the hull:

It's like this on both sides, and I was able to light up inside sufficiently to find that the next brace along was also coming unstuck on one side at least.

I'm struggling to comprehend what sort of treatment would cause these layers of fibreglass to basically peel away inside the hull like this. Since nothing can have got to these parts to physically cause them to separate, I can only assume that vibration and bouncing over the years have caused it, and my thoughts on that are that it can't have been glassed all that well if it can peel apart like this inside the hull.

Doesn't really matter though now, as the only important thing is that I put this stuff right and prevent it happening again.
It's going to be messy and rather emotional I think.

The obvious thing to do at this stage would be to remove the cap, but if you've read this thread you'll note I already tried.
I removed all the rivets round the edge, only to find the cap is bonded to the bracing structure beneath the deck.
Very firmly I might add!

You can see the evidence of this running front to back beneath the deck on top of the bracing here:

And also at the front of these braces where they end in the bow area beneath the front of the deck here:

So realistically I can't see any way that I can remove the cap since I cannot get access to these bonded areas to somehow separate the cap from the bracing it is glued onto. Anyone got experience of this and how to get round this problem?

Removing the cap would be great in terms of allowing me to repair these damaged bits of bracing, and making them super strong for the future.
If I cannot remove the cap (and realistically I don't think I will be able to), I am going to have to carve up areas of the deck in order to get access beneath.

At this point, I couldn't really care about the cosmetic implications of this (ie numerous deck scars once repaired), I just want the boat strong, and pretty is a minor secondary issue. So my plan is that I will have to do lots of careful measuring to establish where this grid of bracing lies under the deck, and then cut out panels in between the bracing structure.

This will give me good access to repair the bracing where damaged, and to inspect where i cannot see.
Once the structural stuff is taken care of I have the matter of replacing the cut pieces of deck.
For this I have two ideas basically.

1) To use some of the cut areas as storage wells beneath deck, and to add hatches into these areas, or
2) To glass in some battens around the edges of the holes where I've removed panels, and across these gaps, then feather in the removed panels, and the paint over the whole deck with anti slip coating to cover over the scars.


Of course as I've mentioned I'd much prefer to lift the cap off so I can do all the repairs without butchering the deck in several places, but I'm assuming that's not really feasible since it's glued down.

Appreciate all suggestions on how best to attack the damaged bits now. I've got a fairly firm idea in my mind as described above, but always good to get experienced feedback, thanks!

Jim