Repairing Replacing Composite Stringers, Bulkheads

[slewit]

I beg to differ. My favorite projects are taking formerly heavy IOs out and putting much lighter OBs on thge same boat. Then taking as much of the plywood,wet plywood from the 60s or 70s and replacing with light weight cored construction. I have done a few boats and had a chine that has been under water by 3 inches now floating above the water by an inch. In dual and more engine applications the outboard lower units could become ventilated when the boat is on plane and even higher out of the water. A single engine will not. Yes I have called this cavitation by mistake instead of ventilation. Sorry

Yes- These are the more extensive rebuilds that need to factor in changes in not only weight but the impact of moving the weights around. Going from Inboard to Outboard can reduce overall weight, but also will shift the boats center of gravity... Also a change such as this can have a big impact on boat structure. You would need to really take a good look at the loads on the transom as the boat was probally not designed to have an big 4 stroke outboard hanging off of it... This is a job for an experienced yard or a very skilled back-yard builder.

Scott

[bly]

Yes- These are the more extensive rebuilds that need to factor in changes in not only weight but the impact of moving the weights around. Going from Inboard to Outboard can reduce overall weight, but also will shift the boats center of gravity... Also a change such as this can have a big impact on boat structure. You would need to really take a good look at the loads on the transom as the boat was probally not designed to have an big 4 stroke outboard hanging off of it... This is a job for an experienced yard or a very skilled back-yard builder.

Scott

Thanks scott for the vote of confidence ? I will now go out of my way not to use your product.

[OReely]

I beg to differ. My favorite projects are taking formerly heavy IOs out and putting much lighter OBs on thge same boat. Then taking as much of the plywood,wet plywood from the 60s or 70s and replacing with light weight cored construction. I have done a few boats and had a chine that has been under water by 3 inches now floating above the water by an inch. In dual and more engine applications the outboard lower units could become ventilated when the boat is on plane and even higher out of the water. A single engine will not. Yes I have called this cavitation by mistake instead of ventilation. Sorry

When the boat is operating at planing speeds the water follows the contour of the hull and exits at the trailing edge of the transom regardless of how she sits at rest. If you've made the boat so light and so fast that the wetted surface is approaching a max width of engine centers + prop diameter plus or minus then I guess you could have a ventilation problem. On an ordinary twin outboard setup this would mean that only 43-45" of the hull (widthwise) is in the water. The boat would have to be extremely fast for this to happen.

Even if that were to occur engine height could be adjusted to compensate.

I grew up calling the anti ventilation plate on outboards a cavitation plate. I was cured during a test and tune with a Mercury guy who corrected me about eight times in one day.

[slewit]

Thanks scott for the vote of confidence ? I will now go out of my way not to use your product.

Hi Bly

Sorry if I offended you.. I was not trying to comment on your particular skill level as I have no idea on your experience in redesigning and restoring boats.

What I dont want to do is gloss over the complexities that can occur when you are doing a major reconfiguration such as going from an inboard to outboard.

My safety at sea concern is that you have developed adquate structure in the transom and redirected the loads properly into the hull and stringer system to take the loads. The load paths for inboards are typically not the same as for outboards. A major transom failure at sea can not only result in a financial loss but in the worst case a loss of life.

Working with the Major OEMS, I can tell you that they spend a great deal of engineering effort making sure that the boats we purchase are safe and structurally sound.

As I have always said no product is for everyone.

So I will wish you the best of luck on your rebuild. Thank you for your consideration.

Scott

[slewit]

When the boat is operating at planing speeds the water follows the contour of the hull and exits at the trailing edge of the transom regardless of how she sits at rest. If you've made the boat so light and so fast that the wetted surface is approaching a max width of engine centers + prop diameter plus or minus then I guess you could have a ventilation problem. On an ordinary twin outboard setup this would mean that only 43-45" of the hull (widthwise) is in the water. The boat would have to be extremely fast for this to happen.

Even if that were to occur engine height could be adjusted to compensate.

I grew up calling the anti ventilation plate on outboards a cavitation plate. I was cured during a test and tune with a Mercury guy who corrected me about eight times in one day.

Thanks OReely for the constructive input !

Scott

[trnsmaster]

pulling the deck on a 24 albe thisweekend to check stringers. have to replace bulkhead its same hull as 233 formula so would be interested in your product if we find severe prob;ems.

[truklodyte]

There is a cheaper way of rebuilding stringers and transoms. Without using wood.It is called high density foam.Highdensity foam will take screws and overlaying of glass as well.Not to do your product any wrong but a lot of projects are scraped when cost over runs the price of boat.

example here is a rudder for a 28ft sailboat made from Highdensity foam.

[slewit]

There is a cheaper way of rebuilding stringers and transoms. Without using wood.It is called high density foam.Highdensity foam will take screws and overlaying of glass as well.Not to do your product any wrong but a lot of projects are scraped when cost over runs the price of boat.

example here is a rudder for a 28ft sailboat made from Highdensity foam.

Hello Truklodyte

High Density foam is a great option. Done properly it will do a fine job that is for sure.

Cost, Increased Labor and increased weight would be the downside.

In Prisma we use 2 lb density floatation grade foam. The result is we can often supply a product with glass for less cost then the bare high density foam.

Our repair product line will feature 3” thick stringers and bulkheads. The wider footprint helps better divide the hull panels. The stringers get a 0/90 fabric on the cap so the 3” top provides better hull support then a thinner bulkhead. The 3” cap also helps provide a generous landing for the cockpit sole.

The load bearing capability of our products come from the glass, as it should be! The foams job is to keep the glass in position and not buckle. Specially formulated tough non-friable low-density foam is used in our product. We have found the tougher foam formulations to impart the best durability onto boats. Many Go-Fast Builders such as Sea Hunter, Cigarette Racing Team and Scarab use our products for this very reason. They are looking for lightweight performance but need the durability to handle extreme environments.

As to Screw holding. May I suggest you try a product we carry called Trevira. This is a polyester mat that can be laminated. It has many uses, one of them being excellent screw holding capability. Many of the OEMS use this product in locations where screw retention is needed. With this approach you are only putting the screw material down in patches where needed allowing you to use lighter weight lower cost materials such as Prisma.

This Picture is of me driving a 1989 Cigarette- The Trevira Bullet, This was the first boat built extensively with Trevira. For me it was my first boat I ever built as we just started Structural Composites and landed our first big commercial customer (Trevira). I learned lamination from the hard working Cubans on Thunder Row Miami. After we finished the boat the guys from Cigarette said “Looks good but it need some hard hours on it”. So Scott Smith (now Dragon Powerboat) trained me and the Trevira guys gave me the keys to the boat, all expenses paid ! Of the boat 250 hours I put about 200 of them on her. Craig Barry is a world-class race boat driver (also now with Dragon Powerboat) he was VP of Cigarette. Once he saw this picture, he purchased it and I was finally in the “Club”.

Higher density foams are cost effective as a replacement for wood transoms and selected other applications. We do carry a line of high density foam so if you would like a price, please contact me. 321-252-4566

Also- Please look for our Banner Ad kicking off our repair product line. We hope to have it uploaded to ReelBoating very soon.

Scott

[truklodyte]

Joe average will be the one restoring or rebuilding their boat so labor cost has no real bearing.The person that is paying to have their boat remodeled would be the people to sell your product to.As for the product I represent it can be for commercial and residentual applications.MunuteMan Boat lifts of Plymouth mass http://mmbhe.com/listings/class_search.pl?...=DOCKSIDE+LIFTS

As for cost It is cheaper than your product as Joe average goes.A lot of manufacturers and suppliers of high density foam products will deliver directly to customer.

[slewit]

Joe average will be the one restoring or rebuilding their boat so labor cost has no real bearing.The person that is paying to have their boat remodeled would be the people to sell your product to.As for the product I represent it can be for commercial and residentual applications.MunuteMan Boat lifts of Plymouth mass http://mmbhe.com/listings/class_search.pl?...=DOCKSIDE+LIFTS

As for cost It is cheaper than your product as Joe average goes.A lot of manufacturers and suppliers of high density foam products will deliver directly to customer.

Interesting as we sell HD core also.

What price data are you using?

Thanks

Scott