Rudder Failures

[neilpride]

The demand never ask for plexus or grid liners, wow, no, they demand afordable boats to sail and enjoy, if Island Packet is still doing full keelers is because they have demand, you can surf in the net regarding hig tech racing boats construction but i think you are going to found Carbon fiber in most hig tech boats, not the tipical first 40.7 , polyester construction, VORS 65 are laminated in CF, IMOCAS have their interior construction Glased , the new 100 ft maxi named COMANCHE Glassed in Cf,
most of this boats are tested in the worst weather posible.Plexus dont have a place in this boats not in the waters they are sailed..

[Polux]

Originally Posted by neilpride

...Plexus dont have a place in this boats not in the waters they are sailed..

I agree that Plexus is not a match for a full carbon boat but less expensive race boats use Plexus to bond structural parts. I had already talked about Akilaria 9.50class and Akilaria 40class racer (you made the favor to post a picture) and most of all one of the most famous offshore racers, even if small, the SF 3200. I believe all these are true offshore racers.

Here you have the SF 3200 "pissing" and overtaking a much bigger sailboat:

https://www.youtube.com/watch?v=QOGL8iaS3Zw

and here another one sailing fast:

https://www.youtube.com/watch?v=syqj5oIZ2nk

The SF 3200 is one of the preferred choices for the transquadra, a French Transat for solo and duo sailors over 40 years of age.

[neilpride]

Im not really interested in see youtube videos showing a small open boat doing well in a race or the sunfast in the Transquadra, but well thx for post it anyway, regarding the Akilaria , first they dont use grid liners , second the bulkheads are actually plexus bonded but with laminate in both sides, pls check the picture again and zoom in, you can see the tabbing tape trough the core .

The sun fast, i believe they are the series who made popular jeaneau, funy to see the grid structure infused in the hull with fiberglass and resin instead of a egg Shell droped with plexus, maybe that and a bunch of detail in cosntruction plus the perfomance under sail made this boats so popular,bulkheads i believe are fg tabbed, but im not sure...

[minaret]

Originally Posted by Polux

Yes of course. Here you have another cheap boat that use bonding agents to structural work:

"The hull and deck of every Shipman boat are chemically bonded, and the hull and the upper flanges of the bulkheads are chemically bonded to the deck using Spabond 345, an epoxy-based adhesive. Once this operation is cured, the final stiffness of the boat is achieved.
All main bulkheads are structural and built in female molds using the same technology as the hull and deck: carbon fibers, epoxy resin and a high-density core, vacuum bagged and oven-cured. The structure is made in female molds, laminated using Sprint and, after oven-cure, bonded to the hull with Spabond 345 material."

Build process - Shipman

Read it carefully. Flanged bulkheads bonded in place are exactly the same thing as a glass tab. It's just that the tab is prebuilt as part of the bulkhead. This is not the same thing as just bonding in a bulkhead, at all. The load is spread over the bond area by the taper in the glass tab. Or, in this case, the bulkhead flange.

[minaret]

Originally Posted by neilpride

The demand never ask for plexus or grid liners, wow, no, they demand afordable boats to sail and enjoy, if Island Packet is still doing full keelers is because they have demand, you can surf in the net regarding hig tech racing boats construction but i think you are going to found Carbon fiber in most hig tech boats, not the tipical first 40.7 , polyester construction, VORS 65 are laminated in CF, IMOCAS have their interior construction Glased , the new 100 ft maxi named COMANCHE Glassed in Cf,
most of this boats are tested in the worst weather posible.Plexus dont have a place in this boats not in the waters they are sailed..

I don't know, I've built some boats like that. We used lots of Plexus; for bonding in those little fiberglass cable tie holders for wire runs.



Weld Mount Complete Wire Tie Kit with Gun

[smackdaddy]

Originally Posted by neilpride

Im not really interested in see youtube videos showing a small open boat doing well in a race or the sunfast in the Transquadra, but well thx for post it anyway, regarding the Akilaria , first they dont use grid liners , second the bulkheads are actually plexus bonded but with laminate in both sides, pls check the picture again and zoom in, you can see the tabbing tape trough the core .

Okay - wait a sec. I looked at a zoomed up version of this (attached). What I see is what I assume to be the Plexus bond (the white) UNDER what looks to be a very thin overlay of glass tabbing (see the air gaps on both sides of the Plexus).

Are you trying to tell me it's that tabbing tape overlay that is providing the real strength here?

Sorry - I don't buy that at all.

[smackdaddy]

Originally Posted by minaret

Read it carefully. Flanged bulkheads bonded in place are exactly the same thing as a glass tab. It's just that the tab is prebuilt as part of the bulkhead. This is not the same thing as just bonding in a bulkhead, at all. The load is spread over the bond area by the taper in the glass tab. Or, in this case, the bulkhead flange.

Wait - isn't that exactly what the image posted earlier from the report shows? A stringer with a bonded flange being superior to a tabbed butt-joint?



This debate is seriously going in circles.

[minaret]

Originally Posted by smackdaddy

Okay - wait a sec. I looked at a zoomed up version of this (attached). What I see is what I assume to be the Plexus bond (the white) UNDER what looks to be a very thin overlay of glass tabbing (see the air gaps on both sides of the Plexus).

Are you trying to tell me it's that tabbing tape overlay that is providing the real strength here?

Sorry - I don't buy that at all.

Which just displays your ignorance about fiberglass construction. Do you think they went to all the work of putting that layup there OVER a plexus bond, if the plexus bond is already stronger than a laminate? That bulkhead tape has a nice wide 5-6" taper onto the surrounding surfaces. It's probably a fairly substantial layup.

[smackdaddy]

Originally Posted by minaret

Which just displays your ignorance about fiberglass construction. Do you think they went to all the work of putting that layup there OVER a plexus bond, if the plexus bond is already stronger than a laminate? That bulkhead tape has a nice wide 5-6" taper onto the surrounding surfaces. It's probably a fairly substantial layup.

If you say so.

However, it certainly doesn't look "thick" to me - nor built-up (as shown in the graphic above). How do you explain what appears to be the air gaps? It really looks like a single ply.

And in any case - if tabbing is superior - why use the Plexus at all?

[colemj]

I missed where the white stuff was determined as fact to be Plexus (or similar). Often times a foam or similar semisoft substance is put between bulkheads and hull before tabbing to prevent hard spots forming. This isn't that?

Mark

[minaret]

Originally Posted by smackdaddy

If you say so. It certainly doesn't look "thick" to me - nor built-up. How do you explain what appears to be the air gaps? It really looks like a single ply.

And in any case - if tabbing is superior - why use the Plexus at all?

Clearness is a sign of a quality lam. I see no "air gaps", just a nice layup. As to why plexus, you have to fillet with something before glassing. Most high end builders prefer something that comes out of a mixing wand, preferably through a pneumatic gun, and that cures quickly. This might be plexus, Proset, or any number of other types of adhesive.

[neilpride]

Originally Posted by smackdaddy

Okay - wait a sec. I looked at a zoomed up version of this (attached). What I see is what I assume to be the Plexus bond (the white) UNDER what looks to be a very thin overlay of glass tabbing (see the air gaps on both sides of the Plexus).

Are you trying to tell me it's that tabbing tape overlay that is providing the real strength here?

Sorry - I don't buy that at all.

You cant acually know the thicknes or the number of layers used, poly and epoxy are clear resins , is laminated take for granted , the hull and bulkheads also look thin layers , i mean from a picture you cant say is thin or thick unless you see a sample, next??

[smackdaddy]

Originally Posted by minaret

Clearness is a sign of a quality lam. I see no "air gaps", just a nice layup. As to why plexus, you have to fillet with something before glassing. Most high end builders prefer something that comes out of a mixing wand, preferably through a pneumatic gun, and that cures quickly. This might be plexus, Proset, or any number of other types of adhesive.

Look just below the corner. See the irregular light areas to the right of the Plexus? See how you also have the irregular light areas on the left side as well. If this is not air - is it just poorly cut glass?

[minaret]

Originally Posted by smackdaddy

Wait - isn't that exactly what the image posted earlier from the report shows? A stringer with a bonded flange being superior to a tabbed butt-joint?



This debate is seriously going in circles.

To reiterate, this diagram is a misleading lie. First, the scale is all wrong. Typical glass tab widths are as you see in the pics above, 4-6" or so depending on scantlings. Typical flange widths are 2" or less. This diagram makes them look the same size. Misleading. Also, it only shows half the equation. If it showed the top and other side of the stringer, in scale, you would see that the glass tab covers a much wider surface than the flange. Misleading. Also, stringers are almost never built as depicted. Usually a foam core is laid in place and laminated over to form the glass stringer "hat section". This means the glass tab is actually part of the stringer, and there is no hard edge between stringer structure and core as depicted. They even removed the fillet! Misleading!!!

[minaret]

Originally Posted by smackdaddy

Look just below the corner. See the irregular light areas to the right of the Plexus? See how you also have the irregular light areas on the left side as well. If this is not air - is it just poorly cut glass?

Yes, that's normal. Just the laminate schedule and/or peel ply edge. No air there! Just thicker glass...