Thread: 1952 Swallow Class Project

This will be a most interesting project with an especially nice working environment. I hope you keep us updated.

I'm sure you will receive good advice along the way but not from me, I will merely be the nosey onlooker.

Cheers
Mike

Hi David,

What a great boat!!!! I think you can simplify the process quite considerably and there is the chance of two-staging it if you want.

This is to kick off discussion .... all of it.

It does sound like the deck was not well thought through if it is the same age as sheathing possibly with the sika being applied improperly and no effective epoxy seal between the beech/sika and the ply. Ah, well not to grumble too much about the past. Could also be bad luck ... but more likely to be bad management.

It is a pity you don't have enough money to get her ashore somewhere. Carefully planned a job like this might not take a lot of time at all, whereas it will be a complete pig doing it afloat. On the other hand by planning it carefully you can reduce the problems by reducing the steps.

First ... to kick off discussion, so long as the deck is not concave anywhere the shape does not need to be modified. Not the slightest ... so you should forget about modifiying the beams and the deck camber. The problems are there because it was not done properly the first time. The evidence for this is the deck rotting as first proof - and the sika lifting probably. (assuming it was done when the hull was sheathed - if it was earlier then it might be a reasonable span.

I do need to push a bit ... there is no way you can get her ashore to work? And if not, do you have a wharf you can pull up alongside while you are working? These two will ease the job very considerably as it gives you somewhere to put things temporarily and gives access to electricity!!!!!

Ventilation is ALWAYS good .. so some thought about that is important here ... but in this case it is not to blame.
1. Take measurements and compare to original plans
Academic interest only. More important that her shape is preserved while you do the work. If it is different from the plan it could have been built different, or has it changed? Also over long periods timber changes shape and to force it back will mean bits of the boat won't fit with each other so well.

There are three things to look at
Fairness - no lumps and hollows or sharp bumps in the structure
Reasonably symmetry - a half inch here or there won't matter if both sides are fair
Twist - this is the tricky one .. when the decks come off she will be quite prone to twisting. You could do part of the decks at a time possibly

2. Strip deck hardware and catalogue
Yes

3. Remove gunwales
Need to check the condition of the deck clamps first ... if they are made of more than one piece or are small in dimension or damaged then the boat will be very weak with the gunwale and deck removed. You will have to remove her from the water to do the work and support her carefully.

4. Photograph, label and catalogue deck planking
Yes - how thick is it? Are the planks screwed to the ply substrate?

4a. Consider getting the ply for the new decks rough cut and then give the undersides three good coats of quality epoxy using the wet on wet method. Then sand to a matte finish so they will bond to the glue you put on the deckbeams. This will be impossible to do on the boat.

Actually ... I am going to push again ... is there no way you can get her ashore ... If the deck beams are fair (in terms of shape) and if you do a lot of prep work and plan carefully there is probably not a big need for a lot of time. Probably two fine days would be enough if you were REALLY organised.

5. Remove deck planking and separate from ply deck.

Caveat ... boats are terrifically weak without any deck. If there are any doubts about integrity consider doing the deck in stages - removing a ply length plus a bit at each time. This is the price for working afloat.

Forget about removing the planking from the old deck for the moment - the new ply deck is completely structural and weatherproof without the planking. There is a good potential for two staging the job. Putting down a new ply deck, epoxying it and going sailing until you get the time and money to do the planking again. Just wanted to mention this as an option.

The second reason is that you really need to get the deck back on pronto

6. Check deck beams and decide on replacements.
Have timber stock on hand or supplier chosen before you start. So you can just go get the stuff. Or if you can identify the problem ones first you can

7. Lay new ply
Yes

8. Sheath deck and scarf into hull
No sheathing - epoxy seal only - three coats wet on wet of a quality epoxy system and sand matte. Sheathing will reduce the glue bond between the planking and the ply - consult PAR who will be drawn to comment on this like the butter side is drawn to the floor.

At this point you could put some temporary paint on the deck and go sailing.

9. Relay beech deck planking
How thick was it? If thin can epoxy down. If thick needs to be screwed and sika'd (or other product).

Australian Beech is a cow to glue ... it is oily like teak ... lovely blonde colour though. So there are some special preparations you have to do if it is thin enough to glue.

Hahaha .. your approach is so novel I had never realised that you were doing the work in a swimming pool!!!!! haha

There will be a huge amount of crap going in the water. Sawdust, woodchips bits of nails and screws ... um new nails and screws ...

MIK

MIK, thanks for your considered response.

Weekend 1 has just been completed and the surprises are a mixture of "I should have seen that coming' and 'oh crap'.

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Attachment 106132

The first question was whether to save the beech deck planking (6mm), and with half the deck off, it's hard to see how I could salvage more than a third of it. It's either rotten underneath, caked in glue or scalloped.

Attachment 106133
Attachment 106136

There's some good news in the deck beams though, they're all in good nick. Though strangely, the original build put no camber in the forward section, from the hatch forward. Maybe this was just to save time/money, but it probably contributed in some way to the water pooling. I'll most likely fix a piece to these beams to at least match the angles of the rest of the deck.

The real issues started to reveal themselves as the sponson and deck came off. There's a series of rotten sections in the deck shelf/top plank, where the rot has spread from the ply deck. I'm hoping further testing will reveal that they're shallow and easily scarfed. It has also run down a chain plate to a stringer and a couple of planks. That's the heart-breaking part.

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Attachment 106135

For good measure, small sections were also found on the keelson and hull floor.

So I didn't go to sleep last night with much confidence. This project seems to be resting on whether or not I can deal with the rot without substantial outlay. And with half the deck still to come off, I'm worried.

So here's a re-evaluation of what needs to be done;

1) Get the deck off
2) Scrutinise every square inch and catalogue rot.
3) Quickly learn what is and isn't in the realms of my repair skills
4) Start offering free beer and wine to anyone with good advice

This all makes ideas like wooding the bilge, putting a stern hatch in, sorting out the patchwork of vintage ribs, arguing about sheathing/epoxy etc seem like a long way away.

I think by next weekend I'll be on here looking for answers to some very specific questions.

Cheers

Howdy,

The rot in the shelf is probably not something to worry about too much .. um in terms of difficulty ... it will be ok.

You will keep rain out of the boat as much as possible?

If the beech is cupped it sounds dubious for re-use. Was it stuck down with glue and then just sika'd (look a Coleridgean apostrophe) between the planks? Any sign of the special tape that is supposed to put down in the bottom of the groove before sika-ing?

MIK

The only way I recommend a laid deck, is over plywood, which apparently is the case here. I have a twist I use and it's widely accepted as the only insurable (literally) way to place lumber over plywood and expect it to stay put. Of course three coats of neat epoxy on all sides of the plywood (especially the end grain), before it goes down. This is the sealer. Bond the sub deck to the beams or fasten the sub deck to the beams, but bond the fastener holes, so any moisture can't get to them. Then sheath the deck with two layers of 6 ounce cloth, set in epoxy. This deck is then ready for the lumber.

Laid decks fall into to general categories, laid and veneer. I'm not sure of the dimensions of the lumber on your deck, but it appears it's a veneer not laid. Both decks wear out and loose thickness from foot traffic, once thinner then say 3/8" they're not salvageable. On a laid deck you would bore for then bond the fasteners, then bung the heads. On a veneer deck you'd usually nail, typically through the groove, which hides the fastener. The exception to this would be a strip planked deck, which is edge nailed (side ways nails), but this doesn't seem to be that type of deck.

I agree with everything Michael recommends, except to add the sheathing element to the substrate under the lumber portion of the deck. The added benefits to this sheathing are: it will truly waterproof the substrate, it can be faired to raise low spots and humps smoothed out and any leaks that might get past the lumber, will be stopped by the sheathing, which saves the substrate and beams and it can stand alone as a deck until lumber is laid over it, .

You're mis-shaped areas (hollows, bumps, etc.) may be a result of the hull distorting. There are a number of reasons this occurs, but it's very common, especially on lightly built craft with substantial overhangs (like this) and particularly when steam bent frames are dainty (again, like yours). From a structural stand point you don't have much "depth of web" in the beam. You see a boat like this is actually a beam, okay a fancy, well triangulated beam, but a beam none the less. The depth of the web is the distance from the top of the beam to the bottom, which in an "I" beam is called the web (the top and bottom are flanges). The upper flange (the deck) is shot, the web is shallow, so, distortions are very likely as the lower flange attempts (vainly) to support the remaining structure. The most obvious of these will be a fore and aft hogging of the lower flange (keel/bottom planking). Other, not so obvious signs will be a "relaxing" of the bilge in some areas and a droop in the deck line as the turn of the bilge sags and bulging just above the turn of the bilge. This occurs when the upper flange (the deck) doesn't bear it's load any more or is weakened substantially and the whole assembly, seems to settle down, literally making the below deck spaces less tall. Gravity has a nasty habit of always pulling in the same direction and this is much like once fine breasts that have seen the ravages of a few decades.

My point, much like Michael's, is you should access the structure. This can only be fully realized on the hard. With an accurate understanding of what's moved, you can then prop, wedge, strap, jack and cuss it back into shape. I mention this because if you install a new sub deck (plywood) over the distorted hull, you'll lock these distortions into the structure by renewing the upper flange aspect of the "beam" and then you're married to it.

Howdy, If PAR and I disagree about boat repair ... go with PAR. He has huge experience in repair over many years and the exposure to see the long term results of what he does.

We both have a good batting average with design and new construction, but he's the bees knees with repair and trad stuff.

MIK

I've found it quite rare that we disagree about repairs Michael. Maybe some techniques or applications, but our net results will likely be the same for the most part, despite our different paths to get there. Over the years I've developed a "I don't want to ever see this problem on this boat again" attitude, so some of my methods and techniques could be over kill, though usually well thought out.


I've worked in enough shops to warrant many of these things, knowing some of them might take a little more time or materials. Shop bosses hate this, trying to get stuff out the door as quick as they can, but I've been fortunate enough to have known a few who wouldn't let this type of thing happen. These shops charged a little more, took a little longer, but rarely had a boat come back for a similar problem, maybe to address an issue that arose from the last set of repairs. These places also had unquestioned reputations, which is something to live for if you're in business. Then again, my other half (the one that must be obeyed) says I'm just anal, which could explain much too.

Thank you MIK & PAR, these are considered and generous responses.

Regarding the points you've made;

1) I believe the deck is just veneer glued and then Sika'd, no signs of it being a more complete job than that. Not confident in salvaging too much of it.

2) I indeed plan on following your advice for taking every precaution in waterproofing the ply. Epoxy and sheathing will be the way to go.

3) I am mindful of the structural integrity, though like much of this project, I'm keeping it in perspective. The hull does have some age induced anomaly's, she's a bit hogged etc. I'm keeping an eye on the measurements as the deck comes off and am hoping the deck beams and some clamps will keep her in at least the current shape. I will put more more work into this in the coming weeks.

Again, thank you.

I quick query- based purely on logic, would it stand to reason that a yacht that sits with it's shrouds tight and its' fore and back stays loose would hog under this strain, then if the mast is removed the bow and stern would rise again? Does the gravity of the keel out-rank the overhang of the bow/stern.
Attachment 106282

Rig tension can accelerate issues, but they're "beam" related, not rigging. The bulk of the longitudinal stiffness of the upper flange (the deck) comes from the plywood. When this is compromised, the ends droop. With the decking removed, the problem will increase exponentially. Nothing short of placing her on the hard and jacking the boat back into shape will prevent this or restore the shape. Diagonal strapping was once employed to help prevent this, but plywood has done much to eliminate this need.


It's not especially hard work, though in can be time consuming, as you have to wait for the structure to take a "set" and fasteners restored to hold it. Most often, very careful examination of where structural elements live against other elements, will provide the clues to how much movement has taken place or more importantly, how much you jacked or braced back into the boat. Most times it's small fractions of a inch, but totaled up all these bits of movement equal the sum of the hog, bilge sag, etc. It's near imposable make these types of corrections in the water.

An example would be an old whale boat like yacht I did a few years back. It's fasteners loosened, relaxing the structural elements and things moved. It had a dead straight keel for 80% of it's length, so I blocked up a 10" I beam to the angle of the keel drag (slope of the keel), then dropped the boat directly on top of it. It showed a 10" hog initially, but across the course of 2 months the hull was lowered to eventually land flush against the I beam. After refastening, some structural repairs, she was re-floated. The cabinet and locker doors, companionway slides, etc. would stick, not open or close well, but after they fit perfectly (well, mostly). A clear indication that she's "back in shape" literally.

To answer you question, no the ends of the yacht will not rise up with the rig removed. Wood has a memory and will remain in a position it's been physically held at, if held there for a long time. This is why jacking a boat back into shape takes time. You can't rush it, the wood just gets and cracks or breaks, but it can be "convinced" if you do it slowly.

Again, thanks PAR. This is a steep learning curve.

A question though, regarding the above post, would this be possible if the hull is Dynel sheathed? If jacked up, would the timber & the sheathing move into position evenly under this type of 'convincing'.

Cheers

Dynel doesn't impart any structural strength at all. It's sole ability is abrasion resistance, which by my tests is about 3 times that of a conventional light cloth (8 to 10 ounces)sheathing.

The only way a boat can be "restored" from a distorted condition is by brut force, applied slowly.

An example would be the previously mentioned whale boat conversion. I used several 10 ton bottle jacks, automotive scissor jacks (I love these because they work upside down and sideways, but they don't have much power), hardwood wedges driven under braces, a few come-a-longs and even steel engine mount adjusting shims, all to slowly force the hull back into position.

Every day or so, I'd go out, check the tension of each jack, wedge, etc. and crack a little bit more into it, until eventually a few months later, I'd removed the hog and the boat was able to sit squarely on the I beam.

The bilges still sagged a bit at this point, but now I could use the weight of the boat to shove the bilge turn up, which in turn closed up the gaps along the deck beam to sheer clamp joints.

After I was satisfied with the "new" shape, I diagonally strapped it down with 1/2" plywood ripped into 6" wide lengths. I used drywall screws, right into the planking, intentionally missing frames. This served to "freeze" the structure, so I could begin removing fasteners, restoring their holes and refasten the framing structure and other repairs.

The last thing done, which is typical was planking replacement. The structural frame work was now solid again, so I removed every other plank, made new ones and rehung them. With half the planking solid and all the frame, the other planks where removed and replaced.

This is a very generic description of the work involved. It's not something I think a novice can perform. Knowing where to place a jack, how much pressure, how to brace without breaking things, etc. is really a matter of experience.

To give you an idea, I used a set of micrometers and feeler gauges to check progress on movement in several locations on the hull. I usually wrote the previous measurement in magic marker directly on the part, so there wouldn't be any guessing what it had changed from. By the time it was all said an done, there where dozens of these marks all over the boat. If I was into number crunching, I could analyze these numbers and offer a time line as to how much movement happened, when and how much it eventually took, what moved first, what moved the most, etc.

Generally in the beginning, you get a good bit of movement, by placing jacks or wedges, but you get to a point where the jacks and wedges start moving the boat too far in one direction and not enough in another, so you have to adjust and/or move or add jacks. This is the part that really takes experience. On this project I moved all the braces, jacks and wedges at least once, most a few times, to slow down or other wise change the type of pressure I was exerting on the structure. I only broke one bilge stringer, which was possibly cracked before hand. The first time I did this (30 years ago), I broke the keel on a power cruiser. I got greedy and jacked into much pressure and it had snapped over night, when I checked the following day. I was able to scarf in a repair, but it didn't make the owner especially happy.

In short, you can apply a lot of torque with these things. If it's too fast or in the wrong place, things will break.

To directly answer you question, maybe. Dynel is fairly elastic, at least as much so as the epoxy it's set in, which is why it works on wooden boats. If you crank in a lot of movement quickly, it'll likely just sheer from the wood. If it's applied slowly then it might stay attached.

You'll never be able to restore the structure without getting at the plank fasteners. On lightly built boats, the planking usually carries a fair bit of longitudinal loading. You can fix all the frames you want, but with loose planking fasteners, it would amount to a hill of beans. The sheathing has to come off to get at these fasteners, unfortunately.

For what it's worth, planking on traditional wooden builds is considered a "consumable" item. Think of this in terms of a car's air filter, it has a useable service life, then it's done. Generally the garboards and the broads are replaced and the whole boat refastened to give dieing planking a few more seasons, after a few more seasons, then the whole of the bottom at least is replaced. I've seen serviceable planking that was 50 years old, but this is the exception to the rule. 20 years on a well used boat means the fasteners are loose and the garboards shot or near so. After 30 years, you're just kidding yourself about the planking. Rolling sheer has played havoc on the fibers within the planking wood and it's done. Much depends on how hard a life it's had, the level of care and the quality of materials and workmanship during construction. Since it's still alive, we can assume the materials and workmanship quality was good. Possibly also that she may have had an easy life, so look at the previous repairs and upgrades for a clue about her up keep and maintenance. If these appear up to snuff, then she might be worth saving.

I see about a hundred yachts every year in this condition. They're still functioning sort of, but are weak in the knees. The question then becomes, "is it worth it". 95% of the time it's usually not. This is a sad, but unfortunate truth about well worn wooden boats, especially if lightly built. I'm currently cutting up a 1960 Chris Craft. I've removed all her metals, engine, controls, gauges, etc. I've also taken choice pieces of sweet looking mahogany and Douglas fir, but the rest will be chainsawn down to a pile, and carted off to the local land fill. The boat was in better condition then yours, but lacked resale value, it wasn't a particularly notable type, nor carried anything special by way of engine, transmission, etc. Repairs would have rivaled buying another example of the same boat in better condition so, it was time to scrap her. A sad reality, but quite common.

Thanks again PAR, certainly things are starting to gain perspective now I’m getting a few weekends into the project.

I am sure many of the readers here would indeed place this yacht in the 95% you describe above, but only barely. She has indeed had an easy life, spending most of her time on a lake, and the quality of the original workmanship appears to be good. Some strange decisions have been made in her life; including fiber-glassing over the original ribs (now developing some rot underneath), sheathing the hull but not running the glass over the deck shelf, using reclaimed timber for the shelf and not plugging the old holes that came with. The list does go on a bit.

So what now?

As I mentioned, a picture is beginning to emerge. I’m hoping a régime of glycol and injected epoxy will steady the milder rot already found, whilst I will replace parts that are beyond this.

I new deck will go onto the existing beams, but I will shape some of them with a new top piece so as to get a more attractive and practical camber.

After this, the rigging goes back on as is, the sails are not replaced and I’m hoping there’s 5 years of running up and down Sydney Harbour to be had. Considering the resources and time available, this would be a perfectly acceptable result to me.

So she may not win any classic awards, but getting her to her 60th birthday will have to do.

Will keep you posted.

Hi,

I have come across this forum. I'm in the UK and have a Swallow S91. I was interested to see that you have a different sail plan to what we have here in the UK.

Do you have a photo of the rig showing the complete main and jib.

I'd also be interested to see a picture of how you sheet the jib to the deck and the fitting that you use.

You can email me directly on [email protected]

Thanks

Guy Knight