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Deleted User YDKXO
Guest
Yup thats probably a better solution than the block idea and simpler to make
Blue Angel (Canados 70s) Rebuild thread
- Thread starter BartW
- Start date
MapisM
Well-known member
Not that this changes the nature of the problem one bit, but actually the moorings which are more critical for those Canados fairleads are rather alongside than stern to, because that's the situation where the fairlead is pulled sideways.
If the main stern lines are pulling straight, practically the whole load is on the cleat, because the lateral load is negligible.
Bart said that he was moored alongside in Rome, and IIRC when he suffered a similar damage on stbd side in Toulon (moored stern to) it was because he had also crossed lines attached to the same cleat.
In fact, the stbd fairlead was pulled inward, as opposed to the port fairlead which was pulled forward when moored alongside.
In other words, if those original fairleads would have always been used only for stern to mooring, without any crossed lines (or attaching the crossed lines only to the other external/lower cleats), probably they would have never been damaged.
But of course, that's no excuse for not making them strong enough to withstand lateral loads!
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Deleted User YDKXO
Guest
I disagree, Mapism. Sometimes I see my own boat moored stern to with just 2 stern lines going back to the quay and it often swings violently from side to side when it's windy, putting enormous lateral force on the fairleads. I think your boat, being a heavy D boat, might move a lot less than light planing boats like mine and Bart's. If you put out crossed lines as well to stop the swinging from side to side, yes of course it puts a big lateral load on the fairleads but the load is more constant and snatches far less. IMHO, Bart's problems come from many years of stern to mooring loading the fairlead which is supported by an inadequate structure. In any case as you say it doesn't matter because I'm sure he's going to strengthen the whole assembly now to withstand a hurricaneNot that this changes the nature of the problem one bit, but actually the moorings which are more critical for those Canados fairleads are rather alongside than stern to, because that's the situation where the fairlead is pulled sideways.
If the main stern lines are pulling straight, practically the whole load is on the cleat, because the lateral load is negligible.
In fact, Bart said that he was moored alongside in Rome, and IIRC when he suffered a similar damage on stbd side in Toulon it was because he had also crossed lines attached to the same cleat.
And the fairlead was pulled inward, as opposed to the port fairlead which was pulled forward when moored alongside.
In other words, if those original fairleads would have always been used only for stern to mooring, without any crossed lines (or attaching the crossed lines only to the other external/lower cleats), probably they would have never been damaged.
But of course, that's no excuse for not making them strong enough to withstand lateral loads!
MapisM
Well-known member
Yep, that's all academic anyway - the need for something stronger is unquestionable.
In the meantime, also this Osculati thing popped to my mind:
http://www.osculati.com/en/cat/Scheda.aspx?id=19041&lang=en
It's available with different angles, so with a bit of luck it might fit precisely BA deck shape, if Bart would want to give a thought to my "flush deck fairlead" (so to speak).
Btw, last year I replaced my bow fairleads with the equivalent straight model (http://www.osculati.com/en/cat/Scheda.aspx?id=2827), so far so good.
In the meantime, also this Osculati thing popped to my mind:
http://www.osculati.com/en/cat/Scheda.aspx?id=19041&lang=en
It's available with different angles, so with a bit of luck it might fit precisely BA deck shape, if Bart would want to give a thought to my "flush deck fairlead" (so to speak).
Btw, last year I replaced my bow fairleads with the equivalent straight model (http://www.osculati.com/en/cat/Scheda.aspx?id=2827), so far so good.
vas
Well-known member
a bit late in the discussion (and struggling for time as usually lately),
I'd vote for lowering the fairlead; on your pic Bart it's obvious it's getting some extra downward forces from being slightly higher than needed...
I'd then go for a few layers of 25mm marine ply cut and formed in shape and make them .5m along the transom and another .5m towards the bow.
I mean epoxy them flat on the deck and screw them down.
This way the fairlead is secured on the 50-75mm high ply all bolts down nicely and then you do as much and as light repair as you wish.
No need for forming grp moulds and stuff, just rip all the carp, repair and get it right, probably using a very thin layer of ply to get the curvature more or less right at the end. Then proper sanding (bring it down a bit) a couple of layers of thin mat, epoxy, primer, sanding, etc you know the rest Goes along the process I'm using in repairing and the process the Canados guys used on the bulwark repairs on yours iirc.
If it was structurally possible (not sure) I'd go for dumping the fairleads and getting massive holes a la Azi pic that MM posted.
Trickier and more expensive to get a decent finish though. Would probably have to be solid iroko shaped and fixed on the width of the bulwark; not easy!
cheers
V.
I'd vote for lowering the fairlead; on your pic Bart it's obvious it's getting some extra downward forces from being slightly higher than needed...
I'd then go for a few layers of 25mm marine ply cut and formed in shape and make them .5m along the transom and another .5m towards the bow.
I mean epoxy them flat on the deck and screw them down.
This way the fairlead is secured on the 50-75mm high ply all bolts down nicely and then you do as much and as light repair as you wish.
No need for forming grp moulds and stuff, just rip all the carp, repair and get it right, probably using a very thin layer of ply to get the curvature more or less right at the end. Then proper sanding (bring it down a bit) a couple of layers of thin mat, epoxy, primer, sanding, etc you know the rest
Goes along the process I'm using in repairing and the process the Canados guys used on the bulwark repairs on yours iirc.If it was structurally possible (not sure) I'd go for dumping the fairleads and getting massive holes a la Azi pic that MM posted.
Trickier and more expensive to get a decent finish though. Would probably have to be solid iroko shaped and fixed on the width of the bulwark; not easy!
cheers
V.
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BartW
Well-known member
I have to explain some important details a little better;
1) looking at the stern of the boat, you will see that the fairlead is just above that SS rubbing strake,
this means that inside the fairlead is "almost” resting on a solid piece of wood, which is a stringer / support for the rubbing strake, and functional stiffnes of the hull.
look at the pics of the cross section to see the detail of that solid piece of wood,
on the inside, this is approx. 15 cm above deck level.
2) This plywood construction has lasted over 20years, and because of (ao) the curvature, is much stronger than you would expect.
the damage on port side was from a VERY strong forward snag.
In that direction the construction didn’t have enough strength.
for the temporarily repair, I took the fairlead out, and then i've put in multiple pieces of 18mm ply, firmly fixed inside the gunwale between the fairlead, and a adjacent internal frame, and strongly screwed in that solid piece of wood underneath., and in the remaining ply shell.
My construction survived very well that thunderstorm that caused the cracking on SB side, The plywood around the fairlead on SB side, is in a much better condition.
3) Its different on port side; both the outside and inside plywood shell, have become very bad,
caused from moisture inside the gunwale, as explained in another thread some time ago.
http://www.ybw.com/forums/showthrea...ooden-gunwale-of-Blue-Angel&highlight=gunwale
Only in this stern quarter, the plywood is that bad.
I’m quite confident that replacing the plywood, and put extra plywood reinforcements inside, left and right of the fairlead would be strong enough,
BUT
If we do the work, I would like to improve what is bad on this boat, and imo the strength of the fairlead is not such a problem as you all might think.
My main concern is that a wood construction as such, will alway’s get moisture inside, not only from leaks through gaps, but also from condensation, so not only the wood will become bad after a very long time, but also the paint on it, gets bubbles, and will detach from the wood.
So therefor, I quite like JFM’s idea to replace the complete stern quarter by a GRP construction,
But that is more difficult than the pics and the drawing might show.
In case we want to replace that complete corner by a GRP construction, I can see the following problems:
- Where to begin and end this construction ?
unless we replace everything from the side gate until the transom gate, (which is quite a big job), making fit the gate rebates, and perfectly fitting the teak capping on top, etc..
That’s probably a specialist job, not here in Montenegro,
Or feather that in near the existing gate posts, but than we have seems and possible cracks going over in the wood construction ?
- Inside the gunwale are vertical metal poles for the railing, and functional strength, these are mounted on that solid stringer behind the rubbing strake.
these should be worked around, or incorporated in the construction.
- And finally:
After several repairs of the caulking, we still have small leaks through the deck teak floor on one side deck and on the cockpit, not big, but enoying !
In order to cure this forever, I’m considering (not this year) to get the old teak out, and put GRP or Glass reinforced Epoxy on the deck, before placing new teak. Yes I know this is a major job.
If I do this, I should consider how to “glue” the deck floor GRP with the gunwale inside panels, and if I replace some of these panels by GRP, I should probably do that at the same time…
1) looking at the stern of the boat, you will see that the fairlead is just above that SS rubbing strake,
this means that inside the fairlead is "almost” resting on a solid piece of wood, which is a stringer / support for the rubbing strake, and functional stiffnes of the hull.
look at the pics of the cross section to see the detail of that solid piece of wood,
on the inside, this is approx. 15 cm above deck level.
2) This plywood construction has lasted over 20years, and because of (ao) the curvature, is much stronger than you would expect.
the damage on port side was from a VERY strong forward snag.
In that direction the construction didn’t have enough strength.
for the temporarily repair, I took the fairlead out, and then i've put in multiple pieces of 18mm ply, firmly fixed inside the gunwale between the fairlead, and a adjacent internal frame, and strongly screwed in that solid piece of wood underneath., and in the remaining ply shell.
My construction survived very well that thunderstorm that caused the cracking on SB side, The plywood around the fairlead on SB side, is in a much better condition.
3) Its different on port side; both the outside and inside plywood shell, have become very bad,
caused from moisture inside the gunwale, as explained in another thread some time ago.
http://www.ybw.com/forums/showthrea...ooden-gunwale-of-Blue-Angel&highlight=gunwale
Only in this stern quarter, the plywood is that bad.
I’m quite confident that replacing the plywood, and put extra plywood reinforcements inside, left and right of the fairlead would be strong enough,
BUT
If we do the work, I would like to improve what is bad on this boat, and imo the strength of the fairlead is not such a problem as you all might think.
My main concern is that a wood construction as such, will alway’s get moisture inside, not only from leaks through gaps, but also from condensation, so not only the wood will become bad after a very long time, but also the paint on it, gets bubbles, and will detach from the wood.
So therefor, I quite like JFM’s idea to replace the complete stern quarter by a GRP construction,
But that is more difficult than the pics and the drawing might show.
In case we want to replace that complete corner by a GRP construction, I can see the following problems:
- Where to begin and end this construction ?
unless we replace everything from the side gate until the transom gate, (which is quite a big job), making fit the gate rebates, and perfectly fitting the teak capping on top, etc..
That’s probably a specialist job, not here in Montenegro,
Or feather that in near the existing gate posts, but than we have seems and possible cracks going over in the wood construction ?
- Inside the gunwale are vertical metal poles for the railing, and functional strength, these are mounted on that solid stringer behind the rubbing strake.
these should be worked around, or incorporated in the construction.
- And finally:
After several repairs of the caulking, we still have small leaks through the deck teak floor on one side deck and on the cockpit, not big, but enoying !
In order to cure this forever, I’m considering (not this year) to get the old teak out, and put GRP or Glass reinforced Epoxy on the deck, before placing new teak. Yes I know this is a major job.
If I do this, I should consider how to “glue” the deck floor GRP with the gunwale inside panels, and if I replace some of these panels by GRP, I should probably do that at the same time…
BartW
Well-known member
thats more or less what I did with my tempoarely repair / reinforcement
thanks for posting !
BartW
Well-known member
Not that this changes the nature of the problem one bit, but actually the moorings which are more critical for those Canados fairleads are rather alongside than stern to, because that's the situation where the fairlead is pulled sideways.
If the main stern lines are pulling straight, practically the whole load is on the cleat, because the lateral load is negligible.
Bart said that he was moored alongside in Rome, and IIRC when he suffered a similar damage on stbd side in Toulon (moored stern to) it was because he had also crossed lines attached to the same cleat.
In fact, the stbd fairlead was pulled inward, as opposed to the port fairlead which was pulled forward when moored alongside.
In other words, if those original fairleads would have always been used only for stern to mooring, without any crossed lines (or attaching the crossed lines only to the other external/lower cleats), probably they would have never been damaged.
But of course, that's no excuse for not making them strong enough to withstand lateral loads!
its Obvious that the construction was not suited for the sideway forces on the fairlead,
also during stern to mooring, the spring lines can create such forces as you mentioned,
but we do have now additional cleats on the outside, that I alway's use for the spring lines.
even if we make the fairlead mounting dramatically stronger, I hate too strong side forces on this part of the boat;
you might remember that the gate doors on the stern might "stick" or "not stick" when strong side forces are on the ropes.
choosing another type of fairlead is not needed imo, as explained above.
I can make the fixing of the old fairlead inside stronger, as I have done on P side.
BartW
Well-known member
a bit late in the discussion (and struggling for time as usually lately),
I'd vote for lowering the fairlead; on your pic Bart it's obvious it's getting some extra downward forces from being slightly higher than needed...
I'd then go for a few layers of 25mm marine ply cut and formed in shape and make them .5m along the transom and another .5m towards the bow.
I mean epoxy them flat on the deck and screw them down.
This way the fairlead is secured on the 50-75mm high ply all bolts down nicely and then you do as much and as light repair as you wish.
No need for forming grp moulds and stuff, just rip all the carp, repair and get it right, probably using a very thin layer of ply to get the curvature more or less right at the end. Then proper sanding (bring it down a bit) a couple of layers of thin mat, epoxy, primer, sanding, etc you know the rest
If it was structurally possible (not sure) I'd go for dumping the fairleads and getting massive holes a la Azi pic that MM posted.
Trickier and more expensive to get a decent finish though. Would probably have to be solid iroko shaped and fixed on the width of the bulwark; not easy!
cheers
V.
no need for that buildup Vas, as explained above,
but you make me consider again to just repair it as it was, with plywood sheets and epoxy cover,
and put some sideway reinforcement plywood in first, between the fairlead and the adjacent frames
we have been reconsidering that Gunwale ventilation as discussed in that old threat,
is again on order here.
MapisM
Well-known member
Aha, I didn't consider that in my previous suggestion.
Of course you don't want to cut a structural part to bring the fairlead at the deck level...!
Otoh, maybe you could just solder a s/steel plate under the lower part of the fairlead (wider than the fairlead of course, on both sides), and secure such plate to the solid stringer below, with thru bolts?
That would achieve the same result as a fairlead attached to the deck, from a structural viewpoint, but still keeping the OEM look...
BartW
Well-known member
Mapism, this is one of your posts I copied from the "moisture in gunwale" thread,
and this is more or less what we have in mind to do,
meaning, making small long slot opnenings (2cm x 15cm) just above that solid wooden stringer in the gunwale,
so on the stern, these openings would be 15cm above deck level,
and in addition, I want to make some simple allum vent plates (15 x 5cm) , with vertical slot openings,
paint these panels white, and flush mount them on the gunwale panel, near the top, 10cm below the Teac capping
with this I can create a vertical airflow inside the gunwale, avoiding moisture buildup inside and in the plywood.
MapisM
Well-known member
I see your point, but I'm not sure that it's necessary to have also the top opening, or any vertical air circulation for that matter.
I mean, any external panel on a boat is bound to be covered with moisture almost every night, even those panels which are not enclosed at all.
The problem is avoiding to trap such moisture/fresh water anywhere, because water puddles are what can rot wood in the long term.
If the inner parts of gunwale panels build up moisture, but it can freely flow down and escape without being trapped inside, I would think that is more than enough.
I mean, any external panel on a boat is bound to be covered with moisture almost every night, even those panels which are not enclosed at all.
The problem is avoiding to trap such moisture/fresh water anywhere, because water puddles are what can rot wood in the long term.
If the inner parts of gunwale panels build up moisture, but it can freely flow down and escape without being trapped inside, I would think that is more than enough.
BartW
Well-known member
good idea, simplified version of the earlyer discussed solution,
but
normally you would first close and finish the gunwale,
and only THAN one can fit the dis-assembled fairleads, as these have flanges to go over the edge of the opening in the panel,
so then I'd better fit a SS reinforcement inside, fixed on the stringer, and touching but NOT fixed on the fairlead,
or I could make such a thing from plywood, as I did
BartW
Well-known member
yes about this I'm just not sure,
There is seldom or never a real puddle of water inside, but its exactly that moisture that comes every night, that doesn't dry in there,
this will stay there all winter, and can be absorbed by the plywood. (at least that's what I think)
a little airflow would help to dry this much quicker (I think but I'm not sure) ?!?
MapisM
Well-known member
Well, in principle, with any wooden parts, the higher the air circulation the better. This is also true for wooden hulls and interior furniture.
So, I'm not saying that opening both the top and the bottom doesn't make any sense.
But I would think that what Canados underestimated is the effect of enclosing/sealing completely those gunwales.
I mean, in a 0-100 scale of wood rotting risk due to moisture, a completely open panel (as the single panel gunwales in my boat) is as near to zero as feasible.
Otoh, the fully enclosed boxes in BA (which are obviously much more elegant) are instead pretty close to 100, the way they were built.
Now, if I should try to guess some numbers, by opening just the lower part I would expect a radical reduction - from 100 to somewhere around 10.
The additional top opening could still contribute, and maybe further reduce the risk to 5 or so, but is the hassle worth such marginal further improvement?
Don't take these numbers as anything scientific obviously, I'm just going by gut feeling.
Maybe some of those old Canados folks in Rome, still experienced with wooden construction, can give you also their view...?
So, I'm not saying that opening both the top and the bottom doesn't make any sense.
But I would think that what Canados underestimated is the effect of enclosing/sealing completely those gunwales.
I mean, in a 0-100 scale of wood rotting risk due to moisture, a completely open panel (as the single panel gunwales in my boat) is as near to zero as feasible.
Otoh, the fully enclosed boxes in BA (which are obviously much more elegant) are instead pretty close to 100, the way they were built.
Now, if I should try to guess some numbers, by opening just the lower part I would expect a radical reduction - from 100 to somewhere around 10.
The additional top opening could still contribute, and maybe further reduce the risk to 5 or so, but is the hassle worth such marginal further improvement?
Don't take these numbers as anything scientific obviously, I'm just going by gut feeling.
Maybe some of those old Canados folks in Rome, still experienced with wooden construction, can give you also their view...?
BartW
Well-known member
I went outside took away the gaffa and made some pics
sorry for the quality of the pic, its dark outside
and inside
appart from the repair, there are absolutely no cracks in the old remaining plywood
when I took the fairlead out of its position for the repair, I could see that on the inside all the wood was still in good condition here !
(on port side, not on SB side!)
sorry for the quality of the pic, its dark outside
and inside
appart from the repair, there are absolutely no cracks in the old remaining plywood
when I took the fairlead out of its position for the repair, I could see that on the inside all the wood was still in good condition here !
(on port side, not on SB side!)
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BartW
Well-known member
I tried to,
around Christmas I met Alfonso, he was in Belgium and visited us,
and he called mr Ziggin. ao with this question,
but communication is starting to be difficult as mr Ziggin. is over eighty iirc ;-)
vas
Well-known member
+1000
from MiToS experience, where the circulation is rather good as there's NO "floor" on the enclosed section, all leaks/dribbles/condensation (how???) just runs nicely down damaging the ply hull (but let's not discuss that right now
) that part of the superstructure is just fine.Bart, I'd expect that the best solution is to remove 20-30mm along the bottom of the inner skin (assuming it's not structural which I believe it isn't, but I'm really struggling with time to go back to the thread and examine carefully) all around and leave the vertical structural members showing under as a "feature", or epoxy a strip of iroco in front of each one of them to get the rhythm and dimensions right and be done with. I definitely WOULDN'T cut venting slots high up as you recommend, completely pointless imho and it will be messing with the lines of the aft deck.
If inner skin is considered structural, I'd cut with the fein tool again slots in the middle of each frame and make sure the slot goes all the way to the lower structural member so that any water or condensation just runs off and dries out completely
cheers
V.
vas
Well-known member
I went outside took away the gaffa and made some pics
sorry for the quality of the pic, its dark outside
this is NOT good!
try and sand it and see how deep the soft patch on the bottom left of the pic is. Then do as we did in MiToS, go as deep as you need to get solid material and built on it. I'd remove 4mm out of a larger area get a decent veneer/thin ply, match it and bent it over and epoxy it in. Assuming it's a single curvature, I'd calculate the direction of the curvature and cut parallel grooves on the inside of the 4mm (or whatever) ply so that it bends nicely over (did that on the rubbing strake at the bow on 12mm ply and worked very well.
V.
BartW
Well-known member
the picture doesn't show correctly Vas,
here is a pic made in daylight
the light brown parts, is the temporarely repair, new plywood, several layers filling complete gap between inner and outside shell, and sqeezed left and right between a frame, and the fairlead
you can see the darkbrown solid wooden stringer, just below the corner of the fairlead, I can confirm that this wood is still in impeccable condition,
the dark coller is from moisture under the gaffa tape
on the upper part of the hole, you can see the border of the orriginal plywood shell,
this looks a bit dark but also this is still in perfect condition, no rot at all !
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