Acceptable repair to transom planned or not?

Hi all

I just bought an 18' coastworker console boat (my 3rd boat in about 12 years now) and decided due to the age that before selection and fitting of engine (ie either my Yam F50 or the Honda BF75 I was considering) I had some slight concerns about the transom integrity as there had been a couple of holes previously drilled for brackets, and I found a couple of joins I hadn't previously noticed that weren't watertight at the top of the transom etc.

Here's the boat:





I drilled a few small test 'bore' holes in order to obtain samples of the core wood before sealing up again with epoxy, but found evidence of moisture in there in a couple of the holes, although the others were bone dry.

The wood core itself is dry, drills through normally and isn't soft, and smells fresh/isn't discoloured, but when I drilled one of the holes low down on the right hand side of transom, water began to slowly weep out (wasn't much).

The wood extracted through this hole was good still, so it seems to be the case that a couple of small areas on the transom have delaminated slightly from the core/skin, although for the most part it all seems healthy. There's no indication of rot in there.

So the wood is not rotten yet, is dry and solid (to be very clear I have not found any which has any degree of saturation), but that there has been water ingress into the transom between fibreglass skin and the core, and I wish to treat this to ensure strength is retained, before it gets to the point where there is ultimately rot & weakness one day.

I think I have caught this in time so I want to get on the case asap, first to reduce risk of it getting bad, and second so I can actually use the boat this summer since that was the whole reason for abandoning the old boat and buying one that only needed minor jobs doing (so I thought).

My intention on dealing with this is as follows:

• Drill a matrix of holes in top, rear, and underneath of transom - 1) to assess the exact areas where damp has found its way, 2) to facilitate drying of the damp areas
• Address the areas where water has got in (they're fairly easy to spot)
• Once fully dry, inject West System 105/206 mix into all of the holes and clamp the whole area to re-bond in the places which have apparently delaminated slightly.

I've got two books on fibreglass hull repair which recommend this approach where the core is still good which I am confident mine is, and it was one of the techniques recommended to me by West System themselves (when they actually would have sold more of their product to me had I cut out the transom and rebuilt it).

A few people have suggested the only way to be absolutely certain it won't rot after wet has been in there is to chop out the transom and rebuild.
I understand the sentiment, and understand the rationale with this and can't really argue that logic but for me I don't think at this stage that level of work is necessary and I'll explain why:

1) The transom is currently very strong so no problem with weak core that needs to be replaced at this stage.
2) I would expect that once the epoxy has been injected in comprehensively that this will reduce the odds somewhat of water soaking into the core in future since presumably it will act as a sealant to a degree.
3) Once this repair is done, the transom should I believe be good for a long time, but I will check every year or so to ensure rigidity and so on.
4) It will save a great deal of time and cost (although cost isn't that much of an issue here - I'm not doing it this way just to save a few quid).

My rationale is that it's strong now and so as long as I check periodically after drying/treating it will stay that way, and if the worst should happen and eventually it does begin to rot/weaken, I'll identify that and go about replacing the core if & when that becomes necessary, rather than now, when I think that is a bit drastic with the relatively good state it's in. I understand why some people would choose to chop it now, but for me as long as I keep an eye on the health of it I can't see a big benefit in chopping it out, but lots more cost, time & effort in doing so.

I'd be interested to hear your thoughts on this - people's opinions so far have been mixed with some saying replace the core now to avoid future problems, and others who agree with me (including a couple of repair books, my local marine engineer, and West themselves) that it's not necessary at this point, and that as long as I remove the damp and re-bond, then check once in a while, it should be fine.

Thanks for any thoughts on this.
Jim

I understand you not wanting to replace the entire transom but... It will take Years for the wood to dry out. You have no idea how long it has been wet and it WILL ROT eventually even if you inject the epoxy. You MIGHT get a couple of years of service. MIGHT. If you wait to long you could have a catastrophic failure and lose the motor and/or the motor or both. Those people who told you to replace the entire transom were giving you sound advice. It's your boat so do what you want but your method will NOT work for very long. You cannot remove the damp or dry out the wood. It won't happen.

G'day Jim,

Your plan is a logical one. I have an acquaintance that has a number of similar techniques. He drills along the top of the transom, with three or four at the base of the stern as vents, turns the hull upside down, and hooks a vacuum pump system he built, to draw the moisture out. When he feels it's dry enough, he turns the hull right side up, and he injects Smith's clear penetrating epoxy sealer (CPES) to kill the rot fungus and to stabilize the wood. He then uses the vacuum pump on the base holes, to draw it down from the top. Then it's ready for thickened epoxy, fairing and painting.


Of course his projects are not the quickest, he is very meticulous, and a bit obsessive, but they do really turn out quite nice. Then again, he does spend way too much time playing around with epoxies. :rolleyes:

Thanks very much for both replies fellas.
Turning the hull upside down sounds like a right ballache but I can see the sense in doing that. Hadn't occurred to me though I must admit.

It will take Years for the wood to dry out.

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Why?

If it's exposed to air flow, (and heat as I will do), and as a key bit of fact here is only the surface of the wood that is wet (since I've already checked that it's dry beyond the surface of the wood) how would that be the case? That doesn't make sense to me.

I've got logs ten times thicker outside my house that were wet through 6 months ago and are now bone dry purely by stopping the continual exposure to water (ie a sheet over the top of them) and allowing air circulation. I've got ones that have been there for a couple of years which began the same way as being very saturated and wet, yet have dried perfectly and are still of immensely strong structure with no indication of rot at all.

it WILL ROT eventually even if you inject the epoxy.

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My understanding from reading up about rot is that it needs damp conditions in order to propagate and spread, even with what people describe as 'dry rot'. Rot in this context is fungal, which thrives under damp conditions but doesn't when things are dry by all accounts.

So putting aside the first point for a moment (since we disagree about drying out), IF the wood is dry - which it is except for its surface) then any existing rot (there may be spores present but I've seen nothing to indicate the presence of rot that is 'progressed' in any shape or form) then the core remaining dry should surely prevent the spread, especially if it's sealed/treated either chemically (to kill rot as far as is possible) or physically (by adding a barrier - epoxy).

Possible that I don't understand rot properly, but this is the info I've been able to find out so far from various sources online, in print, and people I have spoken to. Apologies if this is incorrect and I would appreciate pointers to info explaining to the contrary.

your method will NOT work for very long.

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If this is true (and I'm certainly not ignorant or big headed enough to just state it's not true), then why is this method oft given as what seems to be a tried & tested approach documented in the books I have (books specific to the subject of fibreglass boat repair), by West themselves, and (some but not all as there is definitely heated division on the matter!!) people who have worked on boats for years without any negative comeback from angry owners who subsequently lost their engine/boat etc a year or several years later.

Surely if this is something recommended at this level then it must have at least some extensive history of being a suitably robust and lasting fix if done correctly and thoroughly? Otherwise if every time this had been tried over the decades it had failed there surely would not be so many 'proper' sources quoting it as a safe and secure means of carrying out a repair.

Specifically re' advice from West, it's not in their interests to tell me this in terms of product sale, so what would their motive be to tell me this if it's not true? I would assume a company like this has done extensive product testing, and from what I can tell are regarded as being the 'defacto' supplier for epoxies in the marine world (for repair stuff if not original construction possibly).

Why would they then suggest this if there's a risk I might later come back and say "You told me this was safe to do and it wasn't, and now my boat is gone and I nearly died in the process. I'm suing you." when they could prevent that risk by saying "Replace it all", AND get more of my money in the process since I'd need way more product to rebuild rather than repair. They even gave the specifics that the moisture level must be 12% or less to be certain of a successful and lasting repair.

You cannot remove the damp or dry out the wood. It won't happen.

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This is a contradiction to your original comment that it will dry but would take years.
Why can wood that's only surface wet, never dry out?

I do appreciate the input and please don't take this post as arguing for the sake of it or 'denial' or anything like that. I'm a science/logic kind of person and I strugggle to accept things without a full understanding of why things are/aren't or knowledge of cause and effect etc.

So I'm asking for clarification with the greatest of respect, since 1) you're trying to help, and 2) I don't know but you may well have tons of practical first hand experience on the specifics of this, which I do not have the benefit of having. Plus 3rd) I could easily have overlooked something obvious that makes an egg on my face mockery of the arguments I'm trying to make.

I'm certainly not entirely ruling out cutting out the wood and replacing it, but given the hassle involved I basically only want to this if there is a solid reason why that should be done now when the transom is still perfectly strong, as opposed to further down the line when it 'might' need doing, but I believe might not, based on the minor state of the problem and proposed treatment. It's easy for me to test periodically that it's strong still so I can't understand the issue given the circumstances.

Again, I'm not for a moment trying to pretend I'm such a smart@ss that I know better than people who've been doing this for years, but for those willing to humour my impertinence and answer my questions I appreciate knowing why the points I've made would be wrong in each case if that is so.
Appreciate the input whether I agree or not as it's all food for thought - Thanks

PS - I like the idea of using CPES prior to the 'proper' epoxy - anyone know if it's available in the UK? Will do some searching on this as I've seen lots of reference to it in my digging.
Cheers!

Presume the likes of this is the same sort of thing as CPES?
http://marinestore.co.uk/Merchant2/...ct_code=HA1457&Category_code=sp-systems-epoxy

But then since I've bought a load of West 105/206 can I not just slightly thin that to achieve the same thing before using the proper thickness to bond?
I realise this sort of thing can be a bit of a hot topic!!

After a quick look online at the obvious font of knowledge (wikipedia - yes I know it's not always the absolute perfect facts but is usually pretty close to the mark) I found stuff backing up the comment I made that I believe all rot including "dry rot" needs moisture to propagate and do its dirty work:

The term dry rot is somewhat misleading, as both species of fungi Serpula lacrymans and Meruliporia incrassata require an elevated moisture content to initiate an attack on timber (28–30%). Once established, the fungi can remain active in timber with a moisture content of more than 20%.

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Which is perhaps why West advised me that I need to try and make sure the wood being worked on is 12% or below for a successful long lasting treatment.
So if this really is the case and I dry it properly, prevent water getting back in where it was doing, and if the wood is currently strong (it most definitely is good at present), there should in theory be no issue with rot getting through the transom, just because at one point there was some moisture in there.

Or can someone tell me why this is not the case?

I would actually rather be corrected if I'm wrong, to potentially avoid problems further down the line.

Jim,

CPES can be used with the west product. I'm not sure of your location, however, since the home port on the stern of your boat reads Isle of Man, I presume you are in the UK. You can find Smith's on Ebay if need be.

Here's a link, another dish if you will, on the table of food for thought:
http://www.star-distributing.com/smith/cpeswhy.html

Cheers Rev Bob

I am indeed on the Isle of Man although strictly speaking it's not actually UK it is to most intents and purposes!

Thanks for the link - similar to stuff I'd already read but with some useful extra info.

Probably can get the stuff on ebay but I bet the shipping to IOM would be despicable cost.
I emailed smiths to ask if they have a uk supplier but I don't think they probably have.

I know that I can thin the west stuff with thinner/acetone and dicsussion on that is done to death on forums already. BUT, since in my case I only want it thinned as a penetrative sealer, and not to try and reconstitute rotten weak wood, I can't see why it'd be an issue like it would be if trying to use for the latter purpose.
Once I've done that and let it cure (following drying of course), I would then add in the proper thickness mix for bonding/relaminating purposes. Might be better in terms of future proofing the core, should water one day find its way in again.

G'day Jim,

The advantage of CPES, is that it will wick into the wood. It has a great adhesion quality about it, and does not fully dry rock solid. The brittleness of the dried wood, along with any spores deep inside the laminate, is where I think a thinned hardening epoxy has it's disadvantages. I use Smith's prior to priming for paint, as well as prior to varnishing. When applied, it only drys about 70%, and remains a bit tacky.

I have no connection to the Company, but I am a true believer in the product.

Thanks Bob

Over the last week or so since I checked the new boat and found this moisture I've done a lot of reading about this stuff and seen a lot of praise for CPES when used for certain tasks. I assumed previously that it was the same as Git-rot but the latter does not seem as well liked from balance of reading a lot of comments in relation to both products.

Never tried either.

Good news is I just got an email back from Steve Smith giving me a link for a european supplier of CPES.
www.lignu.nu

It works out very expensive though unfortunately at 132 EUR for 1.9 litres delivered (£110/$175!!!)
Not sure what volume I'd need to treat mine, but I though it was expensive paying about the same for a whole gallon of West Epoxy, never mind this price! Still, if it needs it and will help prevent problems further on it's money well spent I guess.

When you mentioned brittleness of dried wood, can you elaborate on what context you mean by it being brittle? Do you mean just as it is when fresh? Or something else?Cheers
Jim

Jim,

Well, the effected wood has a loss of the natural soft fibers, as well as the natural oils that give it flexibility. The porous dried wood becomes brittle like honeycomb, think dry grass vs. green grass.

Thanks Bob - sorry I wasn't clear when I asked but I sort of mean what you mean by the affected wood?, ie affected in what respect - rot, or something else?

I'm just asking because like I say the wood in the core seems absolutely fine and not brittle or nasty in shape or form. It's coming out just the same as if I pick up a piece of ply in my workshop and drill a hole in it, so I have no worries at all about the structural integrity of the wood per se, just the fact that its outside surface is wet in some smallish areas.

That's literally just the scale of the problem here, so it's minor but I want to obviously prevent it getting worse.

Hope that makes more sense & sorry for any confusion.

Jim,

I understand what you are saying. The effected wet wood, which from your determinations seems isolated to the entry areas, and your repairs are intended as a preventative measure.

The penetration of the wet rot fungus, wicking into the good surrounding wood, is still active as are the bacteria. When dry, the erosion of the wood fibers will leave tiny voids, which is where CPES really comes to the rescue.


Carry on Sir, you are on the right track.

As I stated previously you have no idea the length of time the wood has been exposed to water and the extent of the saturation. You cannot know this unless you totally reveal it and inspect it. If Water actually came out of the exploratory hole then that is to much water in a transom. I am totally familiar with the Pros and Cons of CPES and it is just thinned epoxy and thinning epoxy is NEVER a good idea and the original mfg of the epoxy will tell you that. It's your boat and you can do what you want, but my 40 years of "Grinding and Glassin" have taught me that your methods are a temporary fix to a Permanent Problem. Vendors can and will say whatever. Time Tested experience Proves what does and does not work. The good Reverend has his friend that seems to think it works Great. I'd probably take his advice and get your boat fixed and just go fishing.

OK. I'll refrain from further comment about this suggestion. For now.

Assuming I did decide to chop out the core and rebuild - I'm not quite sure on how I'd go about this for a few reasons.
Here's my transom:




Now from what I can gather, like most things boat repair related the following is something that's disputed just as much as what's already been discussed on this thread so far. This is in relation to whether the inside or outside skin of the transom is cut in order to remove the core.

Many people state that it's a very bad thing to chop the outside face for reasons of strength as well as cosmetics. Many others disagree and believe it makes no difference, and I have seen plenty of photos/blogs/videos now of boats fixed either way to know that either seems equally common, rightly or wrongly. It seems that any kind of repair in the marine world is subject to pretty heated dispute about whether or not it's appropriate or safe (understandable), but there doesn't seem to be masses of stories that I've found so far with tales of woe from people who did a good job, albeit the wrong job.

I don't like the thought of chopping the outside face of the transom, since to me it would seem that even a well done job is more likely out of the two options to result in a structural weakness. Plenty of others who have already done the job would clearly disagree with my thoughts on this since they have already done this. A quick google doesn't show me stories about recored transoms done this way failing but that doesn't make me like the idea though still.

The problem I have got, is that I can see that trying to remove the core from the inside face of the transom is going to be pretty difficult.
If you look at the inside view photo above, you can see how the deck is fitted on the boat, ie a sealed deck that merges with the transom about half way up it.
So if I attack it from inside the boat I have the option of only revealing half the height of the core (not acceptable really since it would be too tricky to remove the remainder of the core, and too tricky to do a decent job of fitting replacement core). Or the option of hacking back the deck from the transom in order to access the lower section of the core that is currently hidden below deck. This isn't really an acceptable option to me either, and this pushes me towards recoring from outside.

I'm not keen on that, but it's apparent that tons and tons of people have done exactly this, and the web is not awash with stories of such repairs failing later due to a perceived inherent weakness as a result.

IF I was going down this route, my intention would be to preserve the outer skin 'panel' removed, and after core replacement to re bond to the core and to use a fillet joint around the perimeter of the panel, then to add further glassed layer across the full transom to further strengthen the structure and consolidate the layers in question.

This therefore would seem to be on a par with re-cores carried out by others but with an additional provision for extra strengthening in the process. For what it's worth, I have some amount of carbon fabric that I would probably incorporate in there at the same time since I already have it and may as well take advantage of its properties.

Comments are welcome

Forgot to mention - it's fairly apparent where the water has been getting in by the way.

The transom appears to have what i'd refer to I suppose as a 'cap', and where the ends of this meet the rest of the hull there is cracking and visible gaps.
Also, some idiot at some stage in the past has casually drilled 4 holes for an aux bracket without doing it the proper way, and as a result has allowed the demon h20 in.




Planning on trying to carefully remove this cap to further inspect and see how things look beneath. Would be nice to get it off in one piece though if at all possible.

Any tips on achieving that?

I would highly recommend that you post your questions on the iBoats.com forum. It's the absolute best forum on the web for boat repair and restoration. Some of the best Professional boat people hang out on that forum and WILL be MORE than happy to provide you with all answers to your questions. Seeing your pics now, I truly believe your boat is a PRIME Candidate for a Seacast/Nidacore "Pour In Transom" There are multiple threads on the iBoats forum that thoroughly discuss this process with pics, videos and discussion from those that have "Been there and done that. A bit Pricey but one that will Never have to be repeated for the life of the vessel. OH and IMHO cutting the outer skin of the transom to replace it is a Last Ditch method. Yours is NOT that case.

Thanks for the suggestions. I am already a member on there but not posted for years due to other priorities in recent times.
I was actually going to post this thread there at the same time as here, although for some bizarre reason (and I think this is a combination of insomnia caused sleep deprivation and just being blind), I cannot see the icon/button/whatever for starting a new topic once logged in. Will look again though as it's probably there staring me in the face.

I've read up to a certain extent on seacast, and it looks like a interesting and tempting option, and a relatively easy one (specially if it was possible to remove the core without cutting the skins somehow.

My concerns with seacast are primarily the weight of the stuff, and the cost of it. I really don't have a lot of money to spare at present* and typically you need a lot of it by volume, it's expensive, and probably need to be shipped from US which means big shipping cost and taxes to pay on top.
I do already have 1.5 sheets of marine ply in my shed as well which can be used.
I'm guessing there would not really be any issue in recoring with a combination of seacast AND marine ply, ie partially filled with seacast then a single sheet of marine ply (with spacers/guides to keep it central in the space) inserted into the mix and topped up around it, but even then it would cost a huge amount and still weigh a lot.

I gather people use chainsaws to clear out old wood core from transoms, but the bar on mine isn't huge so it'd not reach right down, and since the wood is solid still at present I can't imagine how tricky it'd be trying to get it all out from the top via various hand tools.

I'm interested to know what it is about the photos that makes you say mine would be ideal for the likes of seacast. No real reason, but I'm just curious about what you're seeing that makes you decide that?

And re' your last comment ("OH and IMHO cutting the outer skin of the transom to replace it is a Last Ditch method. Yours is NOT that case."), again, would you mind expanding slightly on what makes you say that? I presume from that you mean that in the case of my boat I ought to attack it from the inside? I'm just not sure how that would be achieved since I really have no wish to begin carving up the deck itself. My boat has a supporting framework running under the deck that makes it very strong, and is filled with separate buoyancy containers throughout, so the last thing I want to do is begin sabotaging that!

Cheers

*I'd REALLY appreciate being spared the hugely offensive timeless classic response to this, which typically goes along the lines of "Well boat ownership is expensive so if you can't afford it you should get rid", or suchlike, if anyone feels the need to try and sound smart.

Well, meanwhile...back at plan A. Presuming by it's location, this is a salt water boat, with sea water intrusion through the unfilled bracket holes, and the hull did not suffer a trailer sinking, filling it with rain water. The boat might not have a soggy stern, with the speculated wood pulp filling. The top of the transom cap would be most likely a source of fresh water coming in, and if removed to repair, a better evaluation can be made. If by chance, the stern has soaked up a bit of the ocean, it stands a very good chance of still being sound, as found in the drilling's.


1. Remove the cap rail for repair, and get a good look underneath.
2. Bore out the lowest of the existing holes, and probe for solid wood.

If in fact, you find you are good to go on a dry-out, cpes, fill, epoxy, and paint. And still have any doubts in your mind, or wish to strengthen the stern further, make up some stainless re-reinforcement backing plates for the engine bracket.

By the way Jim, I think it would look really good with a teak cap rail!

A plate was something I originally was going to add just for additional strength, although I was intending a lot wider and possibly full width. Since I have got marine ply already it'd be easy to add an additional layer of transom glassed in on the inside of the boat if I wanted to, assuming the outboard clamp would still go over it.

I've seen it done on plenty of boats over the year, and while there is always the perennial argument that if it needs one then it needs gutting out, I wouldn't be adding one for the sake of needing one but for strength above what is required since things are always built to a cost! Easy to ask "why bother?", but more difficult to answer "why not!"

A splash well of some sort will be on the cards too as the water here gets pretty choppy and I don't like the idea of how exposed it is compared to my previous boats even though this is a tried & tested design.

Anyway, it's been chucking down for days here but tomorrow is forecast better, so all being well I'll remove the cap and begin further investigation.
The test bore drills I've done so far brought out good wood - to clarify, they went through the full thickness of the core, hence my previous assertions that the wood checked thus far is solid and sound. All of it that came out was good in fact but I need to do a lot more yet.

Just received my moisture meter today so that will help see what's what, although I wouldn't rely on it as such.

When you refer to sea water exposure is it the case that the salt in the water is something that fungal rot cannot tolerate? Or some other reason why it would be less bad than rainwater?


And yes, teak would be lovely as I am very fond of wood and have recently started practising a little more refined woodwork than I traditionally have been capable of so it's certainly an option. That said, it'd still need to be very securely capped beneath that anyway to ensure a proper watertight seal. I do already have some lengths of Iroko, which is very similar and often used in place of teak.

A sad day today since my previous boat was taken away by her new owner. I feel bad about having to concede on time factors when I'd always wanted that specific kind of boat but you have to make decisions from time to time. I have a bit more space at least now!


Hope she gets the TLC she really deserves now with someone who has enough time to see her right, but it did make me fill up a bit to see her get driven away.

Stay the course Jim,

Salt water kills fresh water fungus, salt saturated wood prevents it from growing. The USS Constitution has been sitting in salt water since first launched in 1797, her bottom is still sound, her Restoration repairs to her wood structure over the years have been from rain water intrusion topside. There are organisms in the ocean which do thrive and eat wood at certain depths and temperatures, that's where Titanic's decks went.

I understand missing a boat after change of ownership, but I cheer myself back up when I remember, a boat always owns you. Now yours owns someone else.

Here's a little update - apologies that it's been a while.

I've ended up doing a recore as was being suggested to me, because after a huge amount of pondering and analysis on the matter, I reached the conclusion that I just couldn't ever be certain that the wood had been dried successfully, and I didn't want that question mark hanging over me.
I'm sure this has been said plenty of times before but I'm glad I did it now.

I've faced some negativity about cutting the outer skin instead of inner, but having done a lot of research on the matter I didn't believe it's any sort of issue in respect of strength/safety for a second since it's common practise at many boat yards to do this, and I've yet to find any accounts of ensuing disasters!
Various people have since confirmed that there's no structural/safety reason not to do the job this way, and that it more or less comes down to cosmetics, so this kinda backs up what I'd said/thought originally. Nice to know.

Plus with the benefit of hind sight, re-coring from the inside would not have allowed me to discover the other areas under the deck which were damaged, but that were easily visible having removed the outer transom skin.

So I'm very glad to have done it this way despite going against the advice of some people and ruffling the odd feather or two possibly. That's not my intention though of course.

Progress is coming along really well now though - am very pleased with how things are going, and it's picking up speed by the day almost.

After repairing and re'glassing numerous damaged parts beneath the self draining deck I'm ready to make the new core and drop it in. Have got the marine ply and resin etc. Have made a template for the core and cut the first of 3 panels for the core, and now I've done that I need to make fine adjustments to ensure it's bedded and bonded optimally.

More info and pics to follow, but here's the first test cut ply sheet slotted in approximately last night:

And another short update -

Here's how it is as of last night:




Got lots of gelcoat and sanding etc to be done now, then I can bolt on the engine at last!