Hull / Deck Joint

[Scott Galloway]

If anyone out there remains interested in this topic, I pulled my rub rail off of the port side of Ariel #330 today to find a soggy and fragile prefabricated, once-rigid filler that offered little sealant value to the screw holes that penetrated into the cabin and cockpit locker and were the likely source of a few minor leaks.

I can now see daylight through some of the holes. This once-rigid filler beneath the run rail was augmented by, and in the front section of the rub rail replaced by a thick silicone bead.

I have read all the comments on this joint on this thread and I have read the Ariel Maintenance Manual, but I have yet to see a diagram (engineering drawing of the joint section itself.

I am interested in where the hull section on the Ariel ends and where the deck section begins.

It has been suggested in this thread that through-bolting the rub rail adds stability to the hull/deck seam. This would only be true if the rub rail bolts actually penetrated both the hull the deck sections.  

It has been suggested in this thread that the through bolting of a teak cap rail will add security to the joint. This would only be the case if the hull section extended up and wrapped around the inside of the toe rail.

Superficial examination of my boat's hull/deck joint makes me feel like the hull section might only extend a short distance from the obvious seam beneath the rub rail upward toward but not extending into the toe rail. I base this on the obvious bulge where fiberglass tape has been applied over he seam on the inside before the screws and rub rail were installed.

If my superficial observation were true, then through bolting a cap rail onto the glass toe rail would not strengthen the hull/deck joint.
Furthermore and even more disturbing is the fact that the rub rail screws, since they are right on the joint line, would not offer any structural reinforcements whatsoever.

[Scott Galloway]

As a footnote to my post of June 22, 2002 on this topic, there is a drawing of the hull/deck seam on page 8 of the Ariel Maintenance Manual. It is only a sketch, but I presume from that sketch that the sketch artist believed that the only bond is a cold joint made by applying glass on the inside of the seam. The screws would not in any way hold the hull section to the deck, but instead merely hold the hull section to the fiberglass applied on the inside of the seam, and the degree to which these screws actually penetrate this applied glass would depend on the length of the screws.

I am very interested if anyone has actually seen this joint in cross section or a factory drawn cross section of the seam.

[ebb]

There have been a number of posts on this subject.   I was horrified when I discovered this hull/deck joint.  (of course I'm horrified at nearly everything Pearson did when putting this boat together)  However,  after a third of a century has anybody ever heard of the deck separating from the hull on any of our boats?

It is indeed a butt joint held together with some mat on 338.  I cut thru this bond in many places when I attempted to clean out the seam with a Dremel tool.  Idiots with silicone trying to stop leaks made cleanout imperitive.

I believe Ed added frp tape to the outside to reinforce the joint.  The molded hull/deck butt join is more or LESS 3/16" on 338.  I was even more horrified when I sanded and ground out the cove inside.  Mike wrote about bixel tape.  I found some 4" wide stuff that is sewn together with epoxy compatible mat.  Thick,   takes a lot of syrup to wet out.  Tucked it up into the cove and down over the joint  the whole length of the sheer both sides. Heroic. Hard to do.  Make me feel more better now.

It seemed that grinding in a suitable cove into the seam on the outside to accept the bixel would be more jeopardy than me or the boat could handle, being so thin here.  And hard to fair.  So I opted for the inside fix.

It may be of interest to some that I have also filled in the cove with mahogany strips and slurry because I plan to bolt on a  4 to 3" toerail  and toerail stanchion bases.   what the hell: overkill.
But was it necessary??

[Scott Galloway]

Ebb,

Thanks for the comments.

There have been many posts to this thread, but none of them refute the assertion made by others that the screws holding the rub rail to the Ariel hull deck seam are of structural importance, and that stength to the joint can be enhanced by adding through bolts where the screws once were.

I am still looking for an accurate drawing of the hull deck joint. I have removed the rub rails and cleaned up the joint. The seam is generally very narrow, with only a couple of areas where there is a void or gap. There is no sign anywhere on my boat that the seam has been stressed or widened in 37 years of service, even in the area where mu hul and deck were both damaged on eityher side of this seam by a collision at some time in the past. It therefore appears that the design works well. It appears to me, however, that the screws offer little if anything to the strength of the joint since the screws holes are in the crack between the abutted hull and deck sections.

I suppose that the entire purpose of the screws is to hold the run rail to the boat. In the case of #330, some of those screws are so long that they penertate into the interior o the cabin. Those screws appear to be original, although in some places they have been replaced with a larger screws of the same length.

[ebb]

the rub rail is purely cosmetic.  The screws were put in the seam because they could line up the dinky little thing without thinking too much, and because it might be thicker there so the screw wouldn't go thru and leak,   which it did,   and still does for them who haven't done anything about it. IMVHO.  For whot you need a drawing for?
On 338 the two molds were also a pretty perfect match, with just a few gaps here and there.  At least they got that jigged out ok. Maybe because they fit so well there has never been a problem. The suction principle of boat engineering.  Bye gotta go IMHO

[Scott Galloway]

Based on the sketch on page 8 of the manual, and from comments made by others combined with one spot on my boat in the port cockpit locker where the nature of the joint is evident, I can pretty much see how they built this joint. However I remain interested in the weight of cloth, roving, matt, or whatever Pearson ran from the deck side of the toe rail under the toe rail and down the inside of the hull, in lieu of a thru-bolted overlap in the hull/deck seam, which is what I assuemd that I had before I pulled off the rub rail.

My rub rails is are all off, and I am contemplating options that will reduce leaks and at the same time preserve the strength of the joint. The mahogany rail on the Glissando (Triton) page comes to mind, but I am probably not going to be that adventurous. If the rub rail screws are of no structural value, they could be replaced by slightly larger but shorter screws, which should go a long way toward stopping future leaks into the cabin.

An original enginerring drawing, if available, would give me more information upon which to make a decision.

[ebb]

whatever....

use 5200 when you put the "rub rail" back on again.

[Bill]

The suggested fix beginning on page 37 of the manual works just fine.

[Scott Galloway]

Yes I have read the manual on the topic, however on my boat, #330, someone used rather long screws on the hull-deck seam to hold the rub rail in place. The screws penetrate the inside of the hull in numerous places. In one place, for whatever reason, the screws were replaced by bolts, but this was only in the port cockpit locker area and they were four bolts all in a row. Otherwise the screws were of varying diameters. The smaller screws I took to be original because there was some preformed hard preformed original-looking stuff behind the rail in most of those areas, whereas in the areas with the larger screws, the rail was packed with silicon as were all of the screw holes. What a joy. Lots of loose easy to remove rusty screws.

My hull-deck seam is very tight, with only a couple of voids that more or less just ragged gaps. These could have been mold imperfections or caused by assembly or later mishap.

So I am probably going to fill the screw holes with epoxy if I can flush the silicon out of the holes somehow, and then remount the rub rails with shorter screws bedded in polysulfide. As far as the seam itself, I have wiped it down with a product designed to release silicon, but the gap in the seam is nearly non existant, so it would be inpossible to get all the silicon out without widening the joint in teh process, or to work any polysulide into the crack.

I don't want to use 5200 in the seam. Despite what I have read in the manual, I have been advised by friends who have used the product and from those who have used it on the steel hulled ship on which I serve that 5200 does not remain flexible, can crack, and is difficult to remove. So I will probably go with Boat-Life caulk or a similar product.

My principle concern in all this was the true nature of the seam and the complete function of the screws. I do nto see how a screw that runs through a crack between two pieces of glass into a third piece of glass has any structural function. Therefore as Ebb says, if the screws are purely consmetic, it is my contention that the screws can be shortened significantly to kept them from penertating the hull. This seems to me to be a better alternative to doing a lot of glass work the inside or outside to deal wit the moisture that may creap theorug the screw holes.

Now I do like Ed's idea of glassing the joint totally and forgetting the rub rail,and it sounds like on his boat that was a god solution. One mine, I do not see how any water could enter the cabin except by the screw holes, so correctly beded short screws should do the trick so long as the screws have no structual purpose related to the hull-deck seam.

They don't seem to have a structural purpose to me and they don't seem to have a structural purpose to Ebb, but neither of our last names are Pearson.

My secondary concern is that my boat had extensive crackign in the toe rail gelcoat. I have repaired the cracks, and applied new gelcoat, but I am concerned with the potential for these cracks to return. I am therfroe interested in the dymamics of the hull to deck seam because it appears to me that, on my boat at least, the toe rail may be the weak point that absorbs all hull deck stress.  The options for strengthing this area are interesting to me, especially in light of the options pursued on the Pearson Triton "Glissando" and also the suggestion that additional glass laminations and or glass and wood laminations could be added under the toe rail.

[ebb]

Looking at some of the trash work in 338 I wonder if Pearson had ANY PURPOSE in mind.  Except  $$$.

There are ways of gelcoat repair depending on the damage and type of damage (impact eg) that I too would be interested to read about if Mike will respond.    Hell I was an Arabol and Zspar kinda guy until about a year and a half ago.

PS:  Use 5200, IT DONT CRACK, and it'll hold yer short screwws in place!  Get a generic grout tool to MECHANICALLY clean that seam out!   No power tools like this jerk used.

[Mike Goodwin]

In my opinion these boats are so old the gelcoat is long gone . I believe in patch it and paint it .
As the gelcoat ages it gets very porous ,I'm sure some of you have noticed . It would be rare to see a 1962 boat so well maintained , that the original gelcoat was in good shape .
Re-gelcoat ? Why ? The new poly paints are cheaper, tougher and a lot more user friendly . A good gel-coat job has to be sprayed on and will cost all of what an Awlgrip or Imron job will . Gelcoat should be waxed twice a year , if outside , just like a car . But guess what , they paint Corvettes now too .

No sir, fill the cracks and dings and give her a paint job .

[Scott Galloway]

The longer that I am around boats, the more I learn. One of the things I have learned is that everyone has their own opinion. I am probably not entitled to mine, because I just finished applying gelcoat by brush to all of the white areas on my deck (trunk cabin not included). I do not yet know how it will weather.

However, it looks fine to me at this stage, but I worked with two-ounce batches of gelcoat resin for the final coats.

I used a fair amount of gelcoat paste for the numerous cracks in the white areas as well as the non-skid areas. My boat apparently fought a losing battle with a metal can in SF Bay some years ago, before I owned it, and the radial cracks in the deck and hull were interesting, to say the least.

The cracks needed to be filled with something. I decided to use one pint can of gelcoat paste and a can of whit pigment to fill the cracks, and then two pint cans of $14.99 gel coat resin (with catalyst included) from West Marine top refinish all the white areas of the deck, three bottles of PVA mold release, a couple of bottles of acetone from a hardware store to thin the gelcoat, a six-pack of paper towels, a stack of medical-style calibrated Dixie cups, and a whole mess of gloves at $0.25 each from a surf shop t to a slightly-thinner-than-spray-on consistency. I sanded the resulting gelcoat progressively with 220, 320, 400, 600 and 1500 waterproof sandpaper, and will use surf-shop fiberglass polish to finish the job (as I do on the surfboards that I repair).

Will my gel coat stand up to the rigors of time? I once owned a 1971 Catalina and the gelcoat held up qite well through 1993 or so when I sold it. Of course the job I just did was applied by brush, and not sprayed into a mold in a vacuum bag environment.  I will give you an opinion on my fix in a couple of years.

I remain more concerend about the cracks that once riddled my toe rails. I have not been able to obtain a drawing of the hull-deck seam, so I still am approaching my projects through destructive testing.

As I was installing rub strakes for my dock lines and fenders this evening, I noted that the thickness of the toe rail laminate [from the top surface of the toe rail to the bottom (cabin surface) - gelcoat and glass combined] appears to be approximately 1/2 inch.

Therefore a half-inch screw applied through a commercial one-inch-wide rub strake (with an appropriate gap between the bottom of the rub strake and the top of the toe rail) will not penetrate the laminate. However, one must be very careful when pre-drilling the screw holes, or one has to repair the resulting through-toe rail hole with epoxy, as I had to do twice tonight before I could bed my new run strakes.

It would have been nice to know how thick that toe rail was before I started punching holes. Anyway, it is interesting that the toe rail with the combination of original deck laminations combined with the cold-joint-seam overlay is only one-half inch thick. If this area absorbs the force of hull deck seam flexing, it is no wonder that there are toe rail cracks on my boat. A number of Alberg designed boat of that era had teak capped toe rails and teh Ariel did not.

Now, having been said all of that, I am indeed impressed with my Ariel. The more I dig into the Ariel's hull, deck, and components, the more I trust the integrity of Carl Alberg's design and Pearson's execution. It would be nice if the Pearson had the benefit of our hindsight when they were selecting hull/deck seam options, bedding materials etc.

But this is one nice little boat, and I'd put her up against most boats made after 1960, with the exception of the really expensive ones, and certainly against any boats in her original price range built under the old racing rules where waterline was king.

[commanderpete]

If I recall correctly, the screws used to hold on the rubrail of my boat are # 8 by 3/4 inch flathead. The screws serve no structural purpose.

With all of those screws, you dont need sealant to hold on the rubrail. But, you want to fill the cove on the underside of the rubrail with some type of sealant so no water gets underneath the rubrail to corrode the metal and screws, allow water to get in, and soften the seam.

I also sprayed the underside of the rubrail with corrosion inhibiter before I mounted it.

I had some soft spots at the exterior  hull/ deck seam underneath the rub rail.  I routed them out with a dremel and filled with thickened epoxy. If your seam looks OK, I wouldn't worry about it.

It seems like you just need to fill the old screw holes.

There is very little glass holding the hull to the deck on these boats. But, it is more than enough.

I reinforced the hull deck joint on my boat from the inside. Not necessary, but I couldn't help myself.