Deck Delamination / Core Problems

[Mike Goodwin]

If you could have checked the boat when it left the factory nearly 40 years ago , you would have found it not to be "square and level". Rarely is a fiberglass , or any other boat material, ever symetrical new or old .(Now it is possible to use computer controlled routers to fair a mold, but very pricey.)
 I have seen boats that were an inch and a half wider ( from the centerline) on port over starboard. In other words , don't fret it unless you can see it by the unaided eye ( no levels or strings stretched tight ).
The original molds were made from a 'plug', made by men from wood, lots of room for error. When the mold is pulled from the plug, more error, and when the hull is pulled from the mold, even more error. Then it is all assembled by minimum wage workers, think they really cared how 'square' the boat was. Not until the bulkheads were in and the deck installed does the boat become rigid.
Other than the mold makers and a couple of supervisors, everyone is minimum wage in the glass  shops.
Add on to this that Pearson was pulling several hulls a day from the same molds with the same workers and quality control is not what you would like to think it was ( and these were some of the good boats being made at the time )
Oh yeah, this is in the days before OSHA and the EPA , so respirators are nil and everyone is high as a kite from the fumes ( that's why some of the workers worked so cheap ), could add a little more error?

So 1/16 of an inch is a joke , forgetaboutit !

[Tony G]

Dave
Thanks for doing the gruntwork on that one:D   I've always been super paranoid about the hull changing shape on me as I remove more and more of the interior.  That is why we stopped chopping where we did(main bulkhead & v-berth) and will rebuild before we evacuate any more of the original interior.  I was hoping to get away with using a garden hose water level on the scribed waterline to level and then block the trailer solid.  Follow that up with pad readjustment and THEN start to lay the new tabbing.  I guess only time will tell.  Tony G

[Mike Goodwin]

Dave,

How do you know you had the boat 'plumb' before you started to level ?

The only place most manufacturers tried for accurate shape , was at the waterline.
How do you know you dont have 1/16 more or less gelcoat on the toe rail ? or glass , or resin ?
The hull only has it's original shape , when it is still in the mold.

Lots of boats change shape during a haulout and go back to their previous shape when launched. You are supporting on 6 pads of less than 6 sq.ft. total , I bet. The hull is used to being supported by everything below the waterline.

Want better support while out of the water? Take a 1x6 and run it, full length, between the pads & hull, fore and aft. It will even out the load greatly.

[Greg]

Jeez,  although I am anything but an expert, I am reminded in this case of fixing the kitchen chair by adjusting the legs...lemme see...a little off this one...uh nope, too much...

[marymandara]

Well, the toerail is, I should clarify, visibly taller above the deck one side to the other...that's why we picked a few points to check from. I may not have been real clear in my nomenclature...I was pretty tired. The efforts gone to were to bring the hull vertically "plumb" by "leveling" it athwartships.

My thought, again, is that while I am very aware of the fact a boat changes shape out of the water, I wanted to minimize the distortion caused by the jacks to help the shape be as uniform as possible. The hull shape above the waterline is largely supported by the deck's rigidity...so, rotten deck pretty universally equals a flexier hull. I just didn't want to be doing the deck rebuild in a way that would lock in an unnecesarily deformed shape. It's a sailboat, right? So, the topsides above the waterline become PART OF the effective waterline when the boat is in operation. I have not spent time fairing out the ripples and the roving print-thru for appearance, but for that reason.

One point that I found very interesting, is that the boat is intended to stand vertically on its' keel at haulout...and that anything less than that causes quite a dimensional change in the hull. Similarly, it seems that when the boat IS standing vertically on her keel she is under the least amount of pressure from the jack pads. Literally, as I approached that golden spot the pads all went somewhat loose, including the ones the boat had been inclining towards.

In absence of a semi-reliable choice for a place to plop down a level, I'd say that a guy could feel it pretty well when the hull got vertical. And, if she is standing vertical, you can, as we did, carefully loosen ALL the pads except the v-head until the pads go scuffy-scuffy-wiggle and she'll stand straight up.

It's worth note that a bunk is a flexier situation, no matter how heavy it is built, than blocks and jacks on the ground.
Because of this, I think it is best to check that the boat is "plumb"(or whatever we want to call vertically level) periodically.

The reason this came up in my mind to begin with is that not only is the boat on a bunk, not only have I had to readjust the blocking quite a bit each time the yard have moved her around, but when we had her moved into the building we are now renting she travelled quite a ways across a bumpy yard. The floor in the building is crazy out of plane, so they did some artful shimming under the bunk pads to level it up, and then some leveling of the boat with the jackscrews on their own...overall, she looked pretty good for as caterwompy as the floor is, but I wanted to make sure. Personally, I'm glad I did.

Dave

[Mike Goodwin]

To plumb the boat, you should ( and it's not easy);
find the centerline.
Stretch 2 strings fore and aft dead on the centerline,one above the other about 1' stem to stern.
Hang a plumb bob.
Adjust the boat until plumb.

Why not a level atwartships? Deck units are not made as carefully as the hull and the mounting of such is a 'close enough,is good enough' job.

If you factory scribed waterline is still there, try a waterlevel.

Its the bulkheads and not the deck that hold the shape of the hull .

[Sprite]

What kind of jacks should be used to support the deck, while reconstruction is going on. For example the deck is cut out and the balsa is removed. What should the placement be. I was also
interested in finding out if anyone has used devincell. I was on
the  deck of a fellow who had I think a thirty five foot nonsuch 1980. He had a mushy deck of balsa and he replaced it with devinicell with west systems epoxy. I think it was injected into the deck.  The deck was solid, has anyone tried this and were
there any pitfalls, I was impressed with it.  The reason I am asking is because I've heard about leveling the deck and much about baltec, plywood and various types foam. I had at one time a sample of the stuff. It's grooved does this provide better bonding?



                                      John :eek:

[ebb]

Does anybody read any of this?

[Mike Goodwin]

I dont think so Ebb, just you, me & the newbies !

[Mike Goodwin]

Well let's just see Ebb;

When #45 was out of the water for deck repairs, I made no special attempt to support the deck from below , took the upper skin off and crawled, walked & climbed all over her taking no special care for anything.
She didn't move flex or loose any shape or camber to the deck.

Now you guys know why we don't want you hanging around the boatyard while we work on your boat.
Boatyard rates;
$35 per hour
$50 per hour if you watch
$80 per hour if you help
$100 per hour if you and your brother-in-law help

Mike G

[Mike Goodwin]

Sprite,

It all works, some better than others . Depends on who is used to what. There is nothing wrong with putting balsa back in, hell it worked for 40 years. I just hope I'm around in 40 years to see the decks go mushy again.

[Mike Goodwin]

Hey Ebb, 8 more posts and I hit 500 .Is there a special badge or something for being so responsive or is it argumentative? Which reminds me of my favorite Monty Python skit.

[Sprite]

Hey Mike,

They charge $60.00 just for breathing in the boatyard up here.

All kidding aside it I ve found the board to be helpful. I just pulled up the chain plates and they look like bronze were these original.
My portside suffered a bit of water damage. Where the wall is
should I worry about the bottom part of the deck on that side it's
stained.

                                   Capt. John

[ebb]

Ariel set flat on her keel would be nose down.  

Here on the west coast a boat set on hard is done so on a large block, like a 12x12 under her keel just aft of center with an equally large wedge driven in for more support.   The front of the boat is supported with a huge sawhorse and another wedge creating some flat. 4 three legged adjustable jack stands strategically placed under the bilges.  With these 4 you adjust for balance and make sure the hull is not billowed in by any one,   which is easy to do with the screw pads.

If your boat is not completely stripped and if you are not level fore'n'aft or athwartships you still can estimate your levels and of course your centerline.  

Two sticks longer than 4 feet with equal lines on them will find ennumerable centers.   Eg, place one stick athwartships under the deck at the companionway against the hull, the other stick the same from the other side, bring them together in a straight line across the boat.  Find the center point between two equal lines on the sticks. That is a point on the center line of the boat.

Do this stick to stick lower down using the settees.
Measure a center on the sole.  Sight the 3 centers see if they line up, sort of.

Do this at the compression bulkhead.  Just measure in from two apparently equal outer points and note the center.  Do it in the forepeak, highup and low down.  You might find the center at the cutwater inside or the center of the rudder tube under the cockpit.  

But if you create a number of apparent centers you can take your chalkline and hold it taut thru as many points it will go.  You can't drop a plumb bob, but you can put a straight edge across the settees and right angle up or down.
If you can secure the chaulk line, great.   Do the same with the higher or lower line of points.

You still with me, bro?    Port and starboard are mirror images of each other.  S'posed to be.  Therefor assume it so.  Yer averaging a hundred points until it is cast in epoxy.

If you have lines (string) up, you can carefully move a straightedge close to them and befor you press into them you make a centerline mark on the liner or the sole or where ever.   If you can prop these sticks up temporaryly next to your centering strings.  you can maybe sight them tosee if they line up.  If they do you probably have the center of the boat from stem to stern, and enough waterlines to place any new furniture.  

You now make all your measurements from the center.

You can assume that the settees are relatively waterline, and the sole,  V-berth the same.  And the cockpit deck.  You can make these assumptions thruout the boat, inside and out.  Assume also that the two main bulkheads are parallel to each other.  Also at right angles to the centerline.  So that if you projected lines from a center point using a rafter square it would meet the center of the other bulkhead.  If it doesn't you can check diagonals and get an idea which bulkhead may be out of line.

You can find the centerline of the foredeck using three straightedges to make a triangle that has equal angles at the base.  If your triangle is placed over the toe rail in the same place on both sides AND you are centered on the stem, you instantly have a centerline. (And a bulkhead line, 90 degrees to the CL.)   With some fooling around you can find mast center this way.  Or where the upper shroud plates go, if you think you lost them or think Pearson didn't get it right.

BY the way the forehatch on 338 was exactly in the center. and square.  So here is another place to get centered.
Ohh well, I hope this is helpful to someone.

[ebb]

Hey, we ALL hit 3000 posts!
Congratulations Bill,
this be the best boat site
on the internet, if aye say so myself.

Aye, and a toast:

"Here's to you and here's to me,
Friends may we always be!
But, if by chance we disagree
Up yours!   Here's to me!"