Questions about the roof build of a Oday 27 older model likely 1979 or 78

[Oddvark]

OK, I had a 1976 O'Day 27. FWIW, I added a hatch for ventilation on the roof. It was two layers of glass with a balsa core.

So there is no liner? I have a liner. To be clear are you calling the liner one of the layers of glass? Or is there a layer of glass, then the liner?

It may be two layers of glass and core just on the roof but and extra layer down by the windows??? So assembly would be, glass in mold, balsa, extra glass on the sides but then drop in the interior roof liner so it alone is connected by resin to the balsa on the roof. That seems sketchy to me and a bad way to build.

I "thought" that I had it figured out. Glass, core, glass then a liner with thickened resin to bond in the liner but you say different. I'm not sure of anything at this point. I will have to drill some holes with a small hole saw and see is the only way I see this.

I really wish mine was like the later models which, I think, had carpet or some sort of covering instead of this liner. Another reason I want to get rid of the liner is who knows what sort of musty moldy crap is behind it where you can't clean it. Others on other boats have removed the liner for just this reason. Bad smells and uncertainty about the condition of the hull.

 

[Project_Mayhem]

Do you want a test boat? Then you have the right specimen. If you want a liveaboard, ocean cruiser or cheap boat, then look elsewhere. Cheap boats are the most expensive. O'Days are coastal cruisers at best.

Your O'day has a skin of fiberglass, balsa (plywood in certain areas) and resin core followed by another skin of fiberglass. It's not easy to remove just the skin without damaging the core. It's not easy to remove core without damaging the outer layer of fiberglass. I know this because I did such a repair to my '78 O'day 25. I can say without a doubt it was an awful experience that likely shaved a few years off of my life. Everyone is confirming the same construction techniques on O'days across virtually all of their production history. It's probably the most common technique in cored fiberglass boat building.

People are trying to guide you as they've been down this path. Materials are expensive and there's more work involved than you can imagine. You will encounter both good and bad core. You'll be hoping for bad core because good core is so difficult to remove. You'll need to remove some good core so you can fit a sheet of new core in it's place. I have a very powerful grinder that scares the crap out of me. It still took forever to grind away the core of the foredeck.

Please clearly state your goal. I've read four: live aboard, cheap boat, ocean cruiser and test boat.

 

[Project_Mayhem]

Areas around the windows may differ from boat to boat but the roof and deck is fiberglass/gelcoat, wood and resin core, fiberglass/gelcoat. My O'Day had two layers of fiberglass with no core around the windows. As you can see, @Taly Ho's had core in that area

 

[Tally Ho]

No, just the headliner. The whole purpose is to glue a isogrid to the fiberglass "without" the liner, and it's areas with no real support. I want directly to the hull. I'm not sure how you got that I want to remove the inner, above the interior liner, fiberglass all the way to the balsa. I said and quote,

"...Has anyone cut out the inner liner and how difficult was it? ..."
"...I notice another thread, I'm wading through them, shows a Oday 272 and it appears the whole interior fiberglass laminate is removed. That's what I want..."
"...What I would like to do, assuming the inner cabin liner is separate from the inner fiberglass to to remove the inner liner..."
"...Thanks for all the answers and help. I want to make clear, I'm not sure that it is from some responses. I only want the inner fiberglass liner removed. I'm not interested in new cores..."
"...etc.."

Maybe your confusion is from you saying,

"...The deck has 3 layers, an outer skin, a core, and an inner skin..."

No, "if" the liner is NOT the layer directly above the balsa then it has four layers. outer, balsa, inner over the balsa and then the liner. (I suspect very strongly this is true.I only want to remove the liner. If I do a little gouging on the fiberglass under the liner, I don't care though I would rather not.

My Oday 27 looks like this, much more the worse for wear but certainly not hopeless.

Well I tried the link above picture alone but it won't link correctly, or I don't know the proper method, but it's the full picture above in this link.

Questions about the roof build of a Oday 27 older model likely 1979 or 78

First I want to thank all of you here. I'm going through the threads and there's a ton of useful information. It's much appreciated. Excuse the length. I want to make sure I accurately describe the problem. I have a Oday 27 that I want to experiment with materials, specifically isogrids for...

forums.sailboatowners.com

This is very good advice and exactly what I'm looking for.

The whole point is "if" you add an isogrid it needs to be continuous. If it rest on the liner with a hollow space behind the liner it defeats the purpose, mostly, of adding the isogrid in the first place.

Looking at that photo you referenced, but not of your specific boat, I would say that boat has no liner, and we are looking at finished fiberglass. The main reason I say that is that the deck fittings are thru-bolted through it. On my boat, with a rigid liner, there are holes in the liner to access the nuts on the thru-bolts.

However, where the bulkheads are held in place it looks a lot like my liner.

So, your only option may be to drill a core sample and know for sure.

But I would question the value of the extra layer of isogrid. Is the deck of the 27 not strong enough? Or is it spongy and this is a “shortcut“ fix?

Sorry, just not getting it.


Greg

 

[Oddvark]

I have no idea what people are on about. I asked One, just one simple question. Those that gave me direct answers to this my sincere thanks. But for others this led to a myriad of objections to...things I did not say nor even remotely hint at. . I said, exactly,

"...
What I would like to do, assuming the inner cabin liner is separate from the inner fiberglass to to remove the inner liner. Yes I know there are LOTS of reasons NOT to do this but to be very clear,

THIS IS AN EXPERIMENT..."

That's not mysterious. Not confusing but I got all sorts flak about the core, how taking the top off is too much work, how no one (implied) can do anything on a cheap boat without sending a fortune. I added a little more, a huge mistake, that only bought more objections, more flak, more telling how I'm not an architect so, implying, I'm a fool for trying.

God help us all we can not ask one thing without being raked over coals for a mass of things I did not say nor even hint at. People keep asking what my goal is. I have stated it clearly. Why do I not tell you everything that I want to do, Simply because I get so much grief for one simple question that there's no way in hell I'll open up a new can of worms. I tell some of my ideas, that are far more odd, and next thing you know you will calling me a Chinese spy. (No I'm not a Chinese spy)

People say you can't possibly take an older boat, and , divisively, "just a coastal cruiser" and make anything of it. I disagree. I think this is a very sturdy boat. Far stronger than many new boats with a thin layer of glass and pile of foam. Yes it could use a little more strength, hence the isogrid but it's mostly fine as it is compared to other boats of that age and newer. I have no intentions of arguing or discussing things I didn't say, mean or hint at for expressing a few ideas.

My expectations, from those that directly answered my questions, (and thanks very much, much appreciation), that the inner liner is glued in with thickened resin and with a lot more resin around the openings. Also may very well be, and it wouldn't surprise me, a lot of resin in the middle of the roof where people have said banging on it does not sound hollow.


I still say a hammer drill with a chisel bit is the fastest way to separate it. Multi tool I have but it only goes back and forth. It take ages to saw through all this but the multi tool will certainly be of great use in some locations. Basically a hammer drill chisel acts like a wood splitter as compared to sawing through a tree truck to split it. The strength of the interface betqween the liner and the lower fiberglass is not likely to be a s strong a chisel will wedge them apart.

 

[Oddvark]

It's not easy to remove just the skin without damaging the core. It's not easy to remove core without damaging the outer layer of fiberglass...

Please show me where I said I wish to remove the core. Please show me where I said I wish to remove the outer skin, or the inner, excluding the liner. If you can't, and you won't, please stop telling me how hard it is to do things that I do not want to do.

People are trying to guide you as they've been down this path. Materials are expensive and there's more work involved than you can imagine. You will encounter both good and bad core. You'll be hoping for bad core because good core is so difficult to remove.

Guide me where? If I said I want to go to Detroit and you went on and on about how difficult it was to get to Los Angeles and how I am making so many mistakes going to Los Angles, how I'm obviously not qualified to go to Los Angles without your guidance ...what would you think?. Would you think it a productive discussion?

 

[Project_Mayhem]

Please show me why I said I wish to remove the core. Please show me where I said I wish to remove the outer skin. If you can't, and you won't, please stop telling me how hard it is to do things that I do not want to do.

I think we're a little confused on what you're trying to do. There's a wealth of knowledge from a group of individuals that are genuinely trying to help. Most of us speaking from personal experience. I spent four months cramped in the stern and bow of my 1978 O'Day 25 grinding, cutting and rebuilding the fiberglass and core.

I think one of the confusing things is terminology. A liner and skin may be referring to the same sheet of fiberglass. It may or may not be laminated to a core but usually is. A liner may be the inner skin or it could be an additional skin below the laminated core and outer skin. There are different building techniques that have been mentioned in this thread. I hope this helps to clear up some confusion.

I still say a hammer drill with a chisel bit is the fastest way to separate it. Multi tool I have but it only goes back and forth. It take ages to saw through all this but the multi tool will certainly be of great use in some locations. Basically a hammer drill chisel acts like a wood splitter as compared to sawing through a tree truck to split it. The strength of the interface betqween the liner and the lower fiberglass is not likely to be a s strong a chisel will wedge them apart.

You'll likely need to take a 3/4-1" core sample to be able to clearly see inside. I'd be willing to bet that the roof is two skins of fiberglass with a core laminated in between. This is based on the construction of my own O'Day and the through bolts I'm seeing in your pics.

The fiberglass skins are pretty thin. It's a guarantee that some of the core will come out with the skin. The bond is very strong if the core is still good. I found an oscillating tool and grinder to be my most used tools. I predict that you'll be able to use a chisel bit in the beginning but the structure may become too weak as you progress. I believe that you'll end up using the grinder for most of the work if you want to remove just the inner skin from good core. Bad core will be substantially easier to remove the skin from. This prediction is based on my own experience and I may be wrong.

 

[Oddvark]

I think one of the confusing things is terminology. A liner and skin may be referring to the same sheet of fiberglass

I find it extremely difficult to believe that when I say the inner liner you are confused about what that is??? I don't believe I said anything about skin or core or any of that. And whenever anyone started talking about core or skins I said, over and over, the inner liner. My opinion is you just love to tell people what to do. Even if it has nothing at all to do with anything they are talking about. And it's likely not malicious it's the way you are. I have a relative like that and have know quite a few others that are the same.. Anytime you get to help or you do anything he always, and I mean always, wants tell everyone what to and goes on and on if you don't do what he wants. It's really annoying to constantly be told what to do when it has not the slightest relevance to what you are trying to accomplish. Cops are like this a lot. It's a general personalty trait. Did you used to be or are you cop or security type? It wouldn't surprise me.

 

[dlochner]

he main reason I say that is that the deck fittings are thru-bolted through it.

These are likely after market installed by a prior owner. The tell is the length of the bolts on the port side. No builder would leave those long bolts like that, they would be trimmed and covered with cap nuts (which they do have). If you look closely you will see several plastic plugs in the headliner probably for the handrail on the cabin top.

 

[Project_Mayhem]

I find it extremely difficult to believe that when I say the inner liner you are confused about what that is??? I don't believe I said anything about skin or core or any of that. And whenever anyone started talking about core or skins I said, over and over, the inner liner. My opinion is you just love to tell people what to do. Even if it has nothing at all to do with anything they are talking about. And it's likely not malicious it's the way you are. I have a relative like that and have know quite a few others that are the same.. Anytime you get to help or you do anything he always, and I mean always, wants tell everyone what to and goes on and on if you don't do what he wants. It's really annoying to constantly be told what to do when it has not the slightest relevance to what you are trying to accomplish. Cops are like this a lot. It's a general personalty trait. Did you used to be or are you cop or security type? It wouldn't surprise me.

I'd say I did a pretty good job biting my tongue last night. I tried answering your concerns to the best of my understanding and without judging what you plan on doing. We're merely trying to understand what you are trying to accomplish, in order to help you.

In your case the inner skin and liner are likely one in the same. Others have tried explaining this to you as well. This is why I tried to clarify terminology. If you don't believe me then take a core sample of the roof. If memory serves me correctly, the area around the handrails had a gap between the inner skin/liner and the rest of the laminate. You can check the construction in this area by removing the cap covering the stud/nut for the handrails.

 

[Tally Ho]

These are likely after market installed by a prior owner. The tell is the length of the bolts on the port side. No builder would leave those long bolts like that, they would be trimmed and covered with cap nuts (which they do have). If you look closely you will see several plastic plugs in the headliner probably for the handrail on the cabin top.

View attachment 235859

You could be right Dave.

Greg

 

[Project_Mayhem]

These are likely after market installed by a prior owner. The tell is the length of the bolts on the port side. No builder would leave those long bolts like that, they would be trimmed and covered with cap nuts (which they do have). If you look closely you will see several plastic plugs in the headliner probably for the handrail on the cabin top.

View attachment 235859

I can confirm that those caps are for handrails as my boat had the same ones. I agree that the bolts are likely installed by a PO

 

[jssailem]

Looking at some O’Day 27 images (this one from a 1978 O’Day 27) show what appears to be to be a solid interior fiberglass ceiling to the salon.

Let us not confuse the situation.

Dave annotated the image I posted in # 11. This image is not the OP's boat. It is just an image of an O'Day 27 manufactured in the approximate timeframe identified by the OP, as I noted above in my post. The OP posted an exterior photo of his boat (post # 1).

You may ask why I posted an image, so the OP could use it to compare his boat with the image and see if we are understanding the same issue. I wanted to reduce the confusion that appeared to be happening.

 

[Richard19068]

@Oddvark

I empathize. I think you were clear and a lot of the responses were off on a tangent. I think that happens to a lot of posts. It is not unoften that I read a question then several responses and think "wait, none of that is answering the question asked". It can be frustrating. You are fairly new to posting here but If you have been lurking for a while I think you know that all of the posters answering here were either genuinely trying to add what they thought was relevant information or just interested in what you are trying to do to the boat. Some are bored due to winter layup. I respectfully request you look through what's been provided, ignore what you want, take a deep breath and try to steer the answers back to the original question (which you have).

To reiterate and summarize what I posted I think there are four (maybe even five) layers. The top skin of gelcoat/nonskid, layer of fiberglass, layer of core, layer of fiberglass, "layer" of headliner.

Have at it and please let us know what you find.

 

[Oddvark]

I'd say I did a pretty good job biting my tongue last night. I tried answering your concerns to the best of my understanding and without judging what you plan on doing. We're merely trying to understand what you are trying to accomplish, in order to help you.

Oh I believe you are trying to help, in your own particular way. Even if I repeatably go over, just the liner, just the liner, you have other ideas and those are what matter. And your response is EXACTLY the same as the people that I have dealt with over many years that do this. I'm pointing it out to you but expect you will not pay the slightest attention because no one else that acts this way does. It's just a personality trait some people have.

An example. I had a relative that would have computer problems. Not have the slightest idea of what is wrong and ask me to fix it. Then stand over me and tell me what to do. It's extremely frustrating. And when I point it out they always say,"well I'm only trying to help" in a a sort of, wounded, why are you so mean, way, but in fact they just can not see anyone doing anything without ordering them around. It's really annoying. I absolutely hate it and it's a big trigger for me.

In your case the inner skin and liner are likely one in the same

I doubt that. Why? It makes no sense. It would make the boat extremely weak to lay the outside, lay in core/balsa, then directly lay a, very most likely, cured liner on it. The balsa inner liner would only be a mostly mechanical bond. Weak. I would never do something like that, It's a waste of good fiberglass when you could "chemically" combine a inner light layer of glass to the core, then bond in the already cured inner liner and have a much stronger boat for not much more cost. The inner liner is almost certainly molded on a male mold and to get it off without screwing it up they almost surely had to let it set up. I'm looking at the pictures people posted, and understand I'm extremely appreciative for these and guidance of how the layers are set in, the only thing I'm complaining about this extraneous detours from that information. It looks like what I thought. Outer fiberglass, core, inner fiberglass and then they added the cured inner liner likely with gobs of thickened resin. In later models it seems they have some foam in places.

Your interior is in exceptional condition for the age of the boat BTW

I never said that either. I said

, "My Oday 27 looks like this, much more the worse for wear but certainly not hopeless. ", meaning it has a fiberglass liner. That's not my picture.

dlochner
gave excellent advice here,

"...The headliner can be cut out without too much difficulty. Use a circular saw to cut through the headliner. Adjust the depth so that it does not cut into the inner skin of the deck. Cut it out in sections to find where the thickened resin is located..."

That's likely what I will do with a grinding wheel instead of a blade on the circular saw. Then use a large chisel in a hammer drill to separate it. Places where the, possible installed, resin thickening agent are thick I will likely tape a couple of boards up where they are not, for level, and grind with the saw lots of slots then chisel off. It does NOT have to be prefect. I want to change the way headliners are done to save money while allowing a good look. Fabrics in frames using the isogrid as places to connect the frames. Much like auto interiors, RV's...sorta. They do it like that for a reason. It's fast and saves money but with an infinite amount of fabrics you can get whatever look you want without costly painting and, God forbid, endless sanding.

After a slight bit of thought it might be best to bang around and find where, likely, the inner shell is strongly attached to the inner fiberglass roof and not grind that away. Only on the sides where it separates from the roof.

 

[Oddvark]

I respectfully request you look through what's been provided, ignore what you want, take a deep breath and try to steer the answers back to the original question (which you have).

I have tried, with it appears limited success, until I was no longer amused. At some point you must be direct and point out that this tangential fussing about is of no use. It's either that or go dark.

I understand that there are all sorts of personalities on the web. Some may slighty misunderstand, which is easy as all they need is some clarification and that, I have no problem, but some, as I mentioned, even if they are trying to help, must be directly told that they are not helping. It may seem rude but I've dealt with a LOT of these people as I have a bunch fracticious people around me a lot of my life and can immeditely recognize their behavior. The only way to deal with them is either stop talking to them or show them what they are doing. Frequently, as in almost every single time, they act as if you are some evil troll for pointing out what they are doing. Sigh...it's just the way it is. It's a standard response.

And some people are just constantly arguing because they like it. I do not like it and point that out. While this may seem abrupt it appears to me the only way to gain clarity and show what is exactly what.

I'm damn sure not going to talk about anything else I'm doing. It's too exhausting. I do not like all this fussing about. I can do it, with the best of them, but I do not enjoy it.

 

[Project_Mayhem]

I doubt that. Why? It makes no sense. It would make the boat extremely weak to lay the outside, lay in core/balsa, then directly lay a, very most likely, cured liner on it. The balsa inner liner would only be a mostly mechanical bond. Weak. I would never do something like that, It's a waste of good fiberglass when you could "chemically" combine a inner light layer of glass to the core, then bond in the already cured inner liner and have a much stronger boat for not much more cost. The inner liner is almost certainly molded on a male mold and to get it off without screwing it up they almost surely had to let it set up. I'm looking at the pictures people posted, and understand I'm extremely appreciative for these and guidance of how the layers are set in, the only thing I'm complaining about this extraneous detours from that information. It looks like what I thought. Outer fiberglass, core, inner fiberglass and then they added the cured inner liner likely with gobs of thickened resin. In later models it seems they have some foam in places.

I agree that it could be made stronger but that's a pretty typical construction method. The majority of my 1978 O'Day 25's cabintop and deck were constructed in this matter. The windows were an exception and a believe the area around the handrail screw holes were also hollow. Take a core sample and find out how yours is built.

Maybe I'm wrong. I can only tell you what I found in my O'Day of similar vintage and size.

O'Day was sold off in later years and passed through multiple hands. The history in the later years is a bit murky. I believe the pic of Tally Ho's layup is of an '88. I wouldn't be surprised if larger boats had different construction methods.

I won't pretend to know a much about plugs, molds and whatnot. I know the molding wasn't perfect on my ceiling. The texture faded at the corners and it appeared that it was like this from the factory as there was no signs of alterations.

I never said that either. I said, "My Oday 27 looks like this, much more the worse for wear but certainly not hopeless. "

My mistake. I thought the picture that dlochner posted was of your boat. I edited my post earlier today to remove this comment.

 

[Oddvark]

I agree that it could be made stronger but that's a pretty typical construction method. The majority of my 1978 O'Day 25's cabintop and deck were constructed in this matter.

Sorry to be so blunt but I felt that that was the only way, So my apologies. You have been helpful.

 

[Project_Mayhem]

I will add one more observation as possible insight into the loads involved with this application. My O'Day had a LOT of rotten core. I was surprised whenever I found core that wasn't mush. Despite that I never felt the deck compress under my bare feet, nor was there a significant number of stress cracks due to lack of good core. Don't get me wrong, there were plenty of gelcoat cracks in other areas but the deck was in decent shape all things considered.

I have walked on decks of abandoned boats that you could feel the deck compress as you took a step but none of them were another O'Day. There was one S2 that was like walking on cardboard on a waterbed. I very quickly got off of that one.

I'm not trying to dissuade you from doing your experiment. Just sharing an observation to shine some light on how light the loads may be. I haven't performed any measurements so take it with grain of salt.