Ama Bulkhead Repair on Classic Tri

Folks,

I am a newbie owner of what seems to be an old Hedley Nicol Tri (See the thread entitled "What Nicol do I Own" for more).

The damage needing fixing is in the forward-most bulkhead of the starboard ama, which shows 3 cracks - two to starboard, and one to port. The starboard cracks are at the mid section and top of the bulkhead, and the port crack is at the bottom of the bulkhead.

The cracks seem to be relatively recent; I'm guessing that they occurred within the last 3 or 4 months and were caused by a negligent crew member trying to haul stuff out of the ama.

Another, less feasible cause may be stress on the forward section of the ama, caused by an overly tight mooring line in windy conditions and radically rising and falling tides. These may have twisted and "tweaked" the forward section of the hull resulting in some damage. That said, there was no damage to the fore-ward deck hardware connecting the mooring line to the ama; so I am doubtful that the mooring line could have caused the problem. Please see the previous noted thread for a photo of the lines, along with the damage photos that I have attached herein, and let me know if anyone thinks that the mooring lines could have been in any way responsible for the damage.

With the relevant background material noted above, let us get to the main concern, which is how to fix the damage. My idea is to draw a template of the bulkhead and to cut two identical bulkheads out of 1/4 or 3/8 inch marine plywood. I would then coat the duplicates and the existing 3/8 inch bulkhead with epoxy and sandwich the original bulkhead between the two new sections, using bolts through all three.

Wondering if this seems like an appropriate fix. There are also fillets along the edges of the bulkheads, so I am wondering if I should cut the duplicates a little narrower to allow them to sit flush with the existing bulkhead, then "re-fillet" the sides of the new, reinforced bulkhead.

One caveat to this procedure is that there is a partially destroyed brace at the center-bottom of the bulkhead, which had helped to support the bulkhead from the forward side. It was made of three, laminated 1/4 inch pieces of plywood, two of which have become delaminated and separated from the center piece of the brace. I took them delaminated pieces out, and need to decide whether to rebuild the brace or just rip it out entirely.

I have attached photos of the brace pieces and of the damaged bulkhead. Please copy and rotate the photos as needed for optimum viewing and offer advice on the cause and possible solution outlined above.

Thanks to all,

G2L

 

I don't think you need to sandwich anything. Hit the ring frame (bulkhead) and the hull shell with a sander using some very coarse grit (16, 24, etc.) to "tooth" it up good. Next smooth out any humps and bumps in the fillet, then wet it out with epoxy. Lay a few layers of 12 ounce biax over both sides of the repaired area, with emphasis on 6" of overlap beyond the actual damage areas, including the hull shell. Make up a few boards that can fit over the 'glass repairs, cover them with plastic packaging tape and lightly clamp them in place over the the repairs. This will flatten it out the repair on the ring frame, for a nearly seamless look and insure good contact. Use light clamping pressure, just enough to insure good contact with the goo.

This said, you could make an overlay of plywood, the same thickness of what was originally used and bond this over the damage (essentially, a ring frame shaped doubler). This eliminates the 'glass work and does hide the damage, if it's placed on the appropriate side. Again tooth the crap out of the contact areas, wet out with epoxy, then apply a thickened mix and bring the parts together. A few drywall screws to temporarily hold things while the goo cures, which are later removed and the holes filled. No sandwich is necessary, just replace the broken plywood with more of the same thickness, to restore integrity.

 

It looks pretty straight forward to me too with a couple additions. Check the stringers carefully, the first photo shows what might be a stringer crack, hard to tell with the photo. The frame could be impact damage, double diagonal construction can absorb a pretty good wack flexing but a rigid frame can crack.

Replace the delaminated forward brace for good luck, definitely they are a Nicol item. They are the 3/4" keel knees to help spread loads into the frame, helpful if you bump a log.

Hey you have a Hedley Nicol tri.

 

More Pics, More Specs, More Possible Causes

Thank you guys,

Great advice, and I truly appreciate the detail and time spent helping out a newbie owner. Will start with a couple of comments regarding the damage, then refer you to a new photo.

Firstly, the stringer crack that one of you warned about is not actually a crack; just a grove in the stringer; so that is one piece of good news.

Secondly, the not so good news is that the "knees" are pretty well trashed, and it would be a real project to remake and replace them. Actually, there was only one knee made of three laminated pieces of 1/4" plywood. The two in the photo have fallen off, and the last is precariously attached to the forward side of the forward-most bulkhead/frame. I figure that I will probably just pull it out. Not even sure what is holding it in place except for a bit of very old epoxy.

Also, the whole area is very wet. Not sure exactly why, except that it has been a very rainy season in this part of the tropics. Furthermore, we used to have some jerry cans full of diesel in the hull which gave off fumes for months during the hottest time of the year, and they created a real mess.

We cleaned up all of the hull except the extreme forward area where the frame cracks are because it is so difficult to squeeze in there. Perhaps the oily residue is part of the reason for the "wet" wood. Will do more cleaning and let things dry out before any repair, but the bottom line is that I think I need to scrap the knee - the ONLY one in the hull, by the way.

As a side note, it is interesting to hear that they are an element of true Nicol designs.

Next, I want to talk about my sandwich idea. Though it may not be necessary, I am sort of prejudiced toward doing the fix this way. For one thing, I am a surfer and have done some board repair, none of which I enjoyed and all of which turned out looking pretty ugly : 0. Most importantly, however, is the fact that the cracks in the forward frame are very ragged, and they jut out almost a 1/16th of an inch to the forward side of the bulkhead/frame. Indeed, this factor seems to indicate that someone or something crashed forward into the frame cracking it, and that the damage was not due to mooring line stress or stress under sail.

Also, given the ragged, forward protruding nature of the cracks, I am favoring some kind of sandwich fix because it would seem easier to place an entire frame or half-frame forward of the existing one than it would be to place 3 individual pieces of wood over the three cracks.

Note that it is impossible for any reasonably sized individual to move into the very forward space; so one has to work from the aft section of the frame, using little other than one's sense of touch to know what is on the forward side. Seems easiest to place a new frame forward, stick some bolts through it, and tightening them to an identical frame aft,while working from the aft side of the damaged frame. As would seem obvious, even this fix will not be easily accomplished given the heat, absence of significant light, remaining diesel fumes, and overly tight environs.

Moving onward, I want to add that I measured (as opposed to originally eye-balling) the thickness of the forward-most frame, and, lo and behold, it is actually 1/4" not 3/8". Seems like more evidence that this may be an aft-stretched Cav, but more on that later, in the appropriate thread.

Lastly, please check the additional photo. It shows a delamination (about four inches wide) on the leading edge of the forward starboard wing, near where the wing joins the ama. Originally, I thought that there may have been some connection between it and the damage to the forward frame; but on second thought, this seems unlikely. The frame damage is approximately 3 1/2 feet forward of the leading edge of the wing, so the two do not seem connected or related to any stress which may have been put on the ama by the mooring lines.

Thinking about what caused the wing damage, the obvious answer is "water". but from where? Have not been able to find a source, and I am wondering why is there no other damage.

Also, how can I fix the delamination? Instead of the obvious answer (fiberglass fabric and epoxy) might it be ok to mix up some fiberglass particles with epoxy, lay it a thin coating over the exposed wood, and feather it til it's smooth? Have some glass particles around and, as noted earlier, I have never done any fabric work that I am proud of.

Lastly, please note that the attached photo is not very clear, but it shows the odd, crescent shape of the delamination. Might that be some clue as to the cause?

That's quite enough for now. Hope I haven't stretched or stressed any of you past reasonable limits : )

Thanks to all,

G2L

 

More More Pics

Also, after reading Cav's post above, it got me thinking that maybe "impact damage" of another sort could have caused the frame cracks, if not the wing's leading edge delamination.

We did get whacked by a fishing boat that hit us in a 30knt gale after dragging their anchor. That was about 6 months ago, and it resulted in the damage to the tip of our starboard ama - damage which is visible in the new photo attached.

I gooped up the nose damage with marine epoxy after a couple of clear days because I had nothing else on hand at the time and was worried about it getting soaked in the rain. Due to the forward facing protrusions on the cracks, I did not think that the collision (which pushed our boat backwards)could have caused the crack in the frame. Could I be wrong about this?

If the fishing boat slipped backward on a 1+ foot wave, then it could have hit the starboard, reverse sheer ama nose from above, causing the ama hull to flex downward and perhaps crack the frame, in a manner causing the crack protrusions to face forward?

When we got hit, the waves were only a foot or so high, very close together, in pretty strong wind; so the initial impact could have created a downward, as well as a "backward" thrust.

I suppose that discovering the cause of the frame damage is somewhat of a moot point, as our real concern is how to fix it. However, getting a sense of what may have caused it can really help me to understand the various strengths and weaknesses of the build and what to kinds of potential problems I may need to be particularly conscious of in the future.

Take a look at the new photo, and tell me what you think.

G2L

 

Where to start..... The fish boat might have flexed the ama bow resulting in the frame crack and causing the wing joint overextending breaking the glass which isn't flexible in shear. Yes, it is possible.

The actual tip of the bow bump seems pretty minor, use your epoxy goop.

The wing joint should be carefully inspected. Grind the glass back to good adhesion areas and use stronger epoxy glass like bi axial in that area not just goop because it is a high stress area. I'm actually wondering by the look of the crack if the boat is covered using standard polyester resin which doesn't adhere as well. Inside check the sheer stringers in that area.for any cracks or separation.

Back to the frame, I'd just sister it replacing it from the aft side. 2 pieces is fine, use butt block pieces of ply overlapping the center joint by 4-6 inches a side. An alternative that may seem radical is to cut the ama bow deck carefully off, pull the ring frame and use it for a pattern and install a new one. Replace that 3/4" knee after cleaning and drying things up and re deck joining with the remaining deck with either a scarf or butt block after sprucing things up. Think about it.

This brings up another point. Way back when these boats were built the Australian multihull club kept people connected and in touch with building tips. The light ama frames on the outboard side tended to crack going to windward in storm conditions so the recommendation was to beef them up with a 1/2"-3/4" x4" frame timber sistered to the ring frames on the outboard side. For Nicol owners I recommend you find a copy of the book "Pelinta" written by the president of the club at the time that covered the building and cruising of a Nicol. I actually did this upgrade to my boat for peace of mind in the wilds of the PNW, it is a really horrible job working inside the amas, Vagabond mk2s are even skinnier than Cavaliers to put it in perspective but the boats that were upgraded never broke a frame.

This brings me to the beam. Take pictures, Deep thin frames work in boats as a sandwich structure with an internal truss and are fastened to beefed up bulkheads. Searunners were built with these but Nicols used a different system. The main beam is actually made up of 3 deep narrow beams tied into bulkheads on the center and long timber frames on the for and aft beams. When you said you had a 8" beam I thought someone had dropped in a suitable box beam but 1 3/4" doesn't make a box. There should be 3 within a few inches of each other under the mast area in the main hull extending into the amas.

Back to those keel knees and Nicol history. These boats were designed to sail inside and outside the reef and expected to go exploring the coral and be beached. The ama skegs and main hull keel were actually considered wear items to be replaced when they got too roughed up. With the light construction it was a challenge not to have impacts force the keel through the thin frames and light planking so things like those knees were put in and the ama skegs had heavy glass fairing the joint on the outside with the planking spreading the loads. One Aussie owner also told me about a pair of wide laminated floors (a kind of frame) used in the main hull to spread the keel load. What surprised us both was that my boat had been built with that upgrade. So yes you can probably live without those things but they could help save you in a tight spot like a grounding or beaching in a blow, the little things add up, Hedley didn't do things if he didn't think they were needed to save weight. I'm putting lower ama skegs back on my boat to help keep the skin from being punctured if I get too friendly with a rock in the PNW backwaters.

Don't be intimidated by everything, make a triage list to prioritize and work you way through in order of importance while keeping an eye on everything. Think of these boats more like an airplane and do a preflight check and don't overload. It wouldn't have lasted this long if it wasn't tough.

 

I know it sounds radical, but cutting the bow off, or cutting a 1'x2' slot in the ama to gain good access may be the best option. I am literly having this done on my cat right now, and the quote for cutting the slot, then replacing it and gel coating to match is 9 hours of labor (in my case the daggerboard trunk debonded from the hull and has to be re-attached). Of that 9 hours 5 are in the cosmetic fix to blend the gel coat and make the repair invisible.

 

Too radical, would destroy the lengthways strength imparted by the double diagonal planking and stringers. Removing the deck is about the most radical that should be done here and isn't necessary if you are skinny enough and can handle the claustrophobia.

 

Thanks

Lots to consider, which will take some time and likely result in many more questions.

Thanks for taking the time to make note of all this detail. Truly appreciate your patience and attention to these specifics.

Best Regards,

G2l

G2L

 

Good incentive ...

... too lose a few of those extra pounds : )

G2L

 

Thanks, as usual., for the details.

The odd part about the wing joint crack on the deck is that it did not occur simultaneously with the damage to the tip of the starboard bow. In fact,it appeared about 6 months later, while we were tied up.

Can't imagine that the two might be related except perhaps in a very odd way. We generally enter the boat by cross decking the cat moored next to us. We step on the starboard ama deck about where the wind joint meets the deck, which is about 3 feet aft of the cracked ama frame.

The wife, working in the ama has noticed that when we board the boat in the way described, the cracks in the frames tend to flex and make noise.

Wondering if the lack of "stiffness" in the ama frames could have, over time, flexed the wing joint, resulting in the cracked fiberglass. Pretty sure everything is epoxy as we have used it for repairs and have not experienced any material mismatches.

Also, a trusted boatman who did major work on the boat before and after I bought it (as well as the broker who sold it to us) all verify that epoxy was used over the glass.

After years in place, some of it is fairly brittle, has lost some of its cohesion, and has taken on a dark brown color. Don't know if any of that might be a clue as to the identity of the material, but it may be worth noting.

Thanks again,

G2L

 

Do you have the 1/4" ama floor panels? I didn't notice them in the photos in the other thread. Fastened to the stringers at about waterline level they beef up the boat stopping any panting/flexing. A 4-6" hole in the center allows bilge access, can be oval They are one of those details that make a big difference.

Frame flexing when you step on the deck illustrates ring frame importance. That could have contributed to the wing joint skin delamination or it could have been a side bump on the bow etc......

I always wound up being single when it was time for ama work, the girls are on to me. Do something nice for the wife.

About the moisture, check any repaired areas. I had one pesky, slow seep above the waterline on one ama where the previous owner put a small hole in the skin coming in hot with a tender. The repair looked all right at first glance but polyester bondo had been used which never gave a good seal. It took awhile to find as no water would come in at anchor. Check deck fittings too, finding out if you have fresh or salt water gives the big clue. Also make sure you have good air flow at your mooring with vents etc.... to reduce condensation.

Still need better beam photos, how about from the bow looking aft and in the main hull looking at the bulkhead where the beam goes under the mast. From what I can see it looks like 2 were used tied into 2 ama frames instead of 1 center beam tied into a ama frame with a fore and aft adjacent beams going to larger timbers running down the side. What you have can be adequate if it was done right, any build, especially a later one is going to have the builders ideas incorporated into it. The thing will be to figure out if it was done right. A photo in the ama from the keel looking up between those bow beam/frame areas would help. The beams do fasten onto the faces of the frames.

 

More Beam, interior and crack photos + dimensions - What Think Ye Now?

Back with more details, dimensions, and photos ... Lots more.

Firstly, I do have those floor panels in the Amas. On the ring cracks - we fixed them by sistering in a partial ring on the aft side of the cracked ring, following the advice from you and PAR. Seems very strong.

Did not completely rebuild the knee since it was pretty well rotted out. Instead, we cleaned up the remaining part of the knee, reinforced it with some resin, and added a partial, V shaped "ring" around it. This forward "V" is sandwiched to the sistered ring on the aft side, giving more strength to the area along the ama keel, where the knee is. Hope that will also have a helpful effect in terms of "spreading the loads".

Our next major concern is figuring out what kind of cross beam structure we actually have, and in order to do so, we have included a number of photos and measurements taken over the last few days. I have arranged them in an order that will correspond to my comments below; so please view them accordingly, and forgive the upside-down views in some of the photos.

The first photo is of the companion way which shows the storage spaces port and starboard of the boat's centerline. Note that the storage spaces are open areas that sit between two 1" thick bulkheads. The "ceiling" and floor of these spaces are comprised of 1 3/4" thick beams (about 8 1/2 inches wide). Each beam extends outboard all the way into the amas, the floor beam lying more or less flat, and the "ceiling" beam arching down to meet the floor beam in the amas.

The bulkheads visible in the companion way photo extend (in modified form) all the way out to the amas, thus creating a kind of hollow, arched or angular "box beam" which seems to be the main structural element, or "cross beam" connecting the amas to the main hull. Note that the forward edge of this hollow "beam" also seems to form the leading edge of the aft wing, acting as one of the two main deck beams. In fact, if one looks out the port window, one can see that the leading edge of the aft wing and the forward bulkhead of the cross beam seem to parallel each other almost perfectly.

The second and third photos show an interior view of this hollow structure (not sure exactly what to call it, at this point).

The fourth photo is a shot of the port storage space and galley area. Note the circular hole that is visible through the rectangular hole in the galley frame. The circular hole is in the "extended bulkhead" which forms the forward "wall" of the hollow cross beam.

The 4th photo also shows another key element, which is the small, vertical member near the sink. That is actually the top of a main hull frame, and it marks the port side of the cabin space and the main hull of the vessel. If you draw an imaginary line upward from the top of the vertical member, you will note that it intersects the very bottom of the port side window. Everything outboard of that spot is actually part of the wing deck.

I measured the distance from the port window, outboard, along the leading edge of the port wing, to the point where the wing intersects the port ama, and I came up with a measurement of 92" (7' 8 1/2"). As noted previously, the leading edge of the wing deck and the forward bulkhead of the hollow "cross beam", line up exactly; so to get a better sense of where the beam leads and its possible function, I measured its interior length, starting from the hull frame member, and going outboard as far as the port end of the beam, This measurement turned ot to be approximately 106 1/2 inches (8' 10 1/2"). The fact that the length of the hollow beam was longer than the wing deck's leading edge seems to strongly infer that the beam penetrates the port ama to some extent.

The port ama is between 21-23 inches wide where it intersects with the wing, so it seems to me that the hollow, angular "box beam", or at least the bottom of it, protrudes some 14 1/2 inches into the port ama (92" minus 106 1/2 " = 14 1/2"). That's about 3/4 of the way into the ama, suggesting that our hollow "beam" is not only some sort of "cross beam" but also acts as major support for the ama deck as well. Sound logical?

As suggested above, I'm not sure how to label these structural elements, how they might actually be fitted together, or what all of this might finally infer about the ID of the build; but that is what I am hoping you folks can help me with. Also, the starboard wing and beam measurements are, of course, identical to those discussed above, inferring that both port and starboard features are actually part of a single structural element.

Moving on to photo #5, we see a close up of the galley. This shot simply illustrates more clearly some of the structural elements discussed earlier.

Photo #6 shows a view of the forward storage areas and the forward "hollow cross beam". Its essential structure seems to be the same as the aft "beam" discussed, however, I can't say for sure, since I have not pulled out all my gear and measured it the way I did with the aft structure. What is obvious is that the forward structure marks the forward extent of the main cabin space, just as the aft structure marked the after extent of the main cabin. The central difference between the two structures is that the forward one is attached to the mast support and its face is a full 24 inches from top to bottom, while the aft face measured only 19 3/4 inches. The floor and ceiling of the forward structure are also the same dimensions as found aft = 1 3/4" The aft and forward structures create a deck profile which slants up from the cockpit to the mast, then down to the nose.

Photo#7 is a dark, somewhat cryptic shot of the aft, starboard "box beam" from inside the ama. The beam width is 8 1/2 inches - exactly the same as the bottom of the "box beam" measured in the cabin area. Also, when measured from top to bottom in the center of the ama, this structure was about 8 inches high. Note the bolt barely visible in the top left of the photo and see my past photos for additional views of this area showing two large bolts going forward to aft, apparently there to (in some fashion) secure our "cross beam" to the ama.

Well, as usual, the above probably represents more than enough said : ) Hopefully, the added commentary and photos will help us to better understand the nature and origin of the build and give me some insight as to what kind of structural elements are actually at play here, how seaworthy they may be considered, and how I should label them in any future discussions.

All input always appreciated, and a hearty thanks to all,

G2L

 

More Wing "Crack" Photos, Comments

Regarding the wing deck "crack", we finally got a couple of dry days, so I cut out the 4 inch, delaminated section of the wing deck, which proved (as best as I can tell) to be a layer of fiberglass matte, coated with very old resin, bondo filler and enamel finish paint.

Under all that was the bare wood of the leading edge of the forward wing. What I found there was somewhat disturbing as the delamination seems to be the result of an old repair involving a hardwood "plug" stuck there as an apparent fix to damage done to the leading edge.

I know that the boat has weathered at least one serious typhoon and that when storms threatened, the old "boat boys" used to tie her up using lines wrapped around the wings, in addition to those tied to the deck hardware. This may have caused the damage which the "plug" was supposed to remedy.

The repair is pretty old and was the second delamination that I found aboard, due, at least, in part due to a good looking but less than sound bondo fix. The wood itself, thankfully, seems pretty solid, but the triangular plug seems only to be glued into place.

I put a coating of extra heavy epoxy over it just to seal out the rain and am wondering what exactly to do next.

Hoping folks will take a look see and tell me what they think.

Thanks,

GwL

 

"Repair" or Brace for the Joint?

Also,

Just occurred to me, after looking closely, at the "plug" that it may not be a repair at all, but a kind of brace, supporting the wing deck-ama joint. Could it be some kind of "corner brace", which at the same time is there to add a more graceful line to the joint?

Just some further ideas.

G2L