CAL 30 1966 Cross Beam

My name is Brent Jacobsen and I own CAL 30, hull 55 built in 1966. I am looking for help. I am trying to determine if there is a steal cross beam in this first generation CAL 30. As far as I can see the deck steped mast sits on a compression post, which sits on the threshold of the doorway, under it is a piece of timber that sits on the bottom of the bilge. I can see where the bulkhead is tabed with cloth along the wet locker(port side) and head (starboard side). I can see along the galley seat side of the bulkhead and do not see any signs of a beam. I have had the Ice box out and did not see any signs of a beam there. My family purchased this boat at the Long Beach Sailboat Show in 1966. No modifications have been done. Unless the beam only spans the threshold and is very small and hidden in the molded sole at the threshold, I am at a lose. Any help or insite would be great Thanks Brent J

I've read about the rusting cross beams, and saw the Cal 28 web site detailing the replacement of the rusted out beam. I have what might appear to be a dumb question. Instead of replacing the crossbeam with another steel beam that will eventually rot again, why not seat the mast support on some poured mortar? Mortar gets harder over time when exposed to water and would never rust. The steel part embedded in the motar would be high out of the water. The area appears to be a ready made mold for pouring. It would be heavier, I am sure. (I am doing a lot of mortar work around the house as I write this) I thank everyone for their comments to my main sail problems, and I am mentally prepared for any responses to the above inquiry. Gracias, Bruce Stirling Gangfurd Cal 28 - Hull 82 http://www.stirlinglaw.com/cal28

rua84 wrote: > I've read about the rusting cross beams, and saw the Cal 28 web site > detailing the replacement of the rusted out beam. I have what might > appear to be a dumb question. > > Instead of replacing the crossbeam with another steel beam that will > eventually rot again, why not seat the mast support on some poured > mortar? > Rog Jones posted an explanation that I think I understand. He said that the beam transfers forces such that the hull bears almost none of them. Thinking this through, I'm assuming that the mast sits on the beam, and that the shrouds' loads are carried down to the beam via tension rods. Thus, the shrouds don't pull up on the hull via chainplates, they pull up on the ends of the beam via tension rods. Now I haven't been aboard one of these boats in a long time, and can't verify this, but it's the only way I can understand Rog's explanation. Using mortar would place the mast's downward force on the hull, in one spot, and not on the beam which is supported by shrouds. Have I guessed wrong? Chris Campbell > Mortar gets harder over time when exposed to water and would > never rust. The steel part embedded in the motar would be high out of > the water. The area appears to be a ready made mold for pouring. It > would be heavier, I am sure. > > (I am doing a lot of mortar work around the house as I write this) > > I thank everyone for their comments to my main sail problems, and I am > mentally prepared for any responses to the above inquiry. > > Gracias, > > Bruce Stirling > Gangfurd > Cal 28 - Hull 82 > http://www.stirlinglaw.com/cal28 <http://www.stirlinglaw.com/cal28> > > > >------------------------------------------------------------------------ > >No virus found in this incoming message. >Checked by AVG Free Edition. >Version: 7.1.394 / Virus Database: 268.9.0/368 - Release Date: 6/16/2006 > >

--- In Ca… [at] yahoogroups.com, Chris Campbell <clcampbell@...> wrote: > > > > rua84 wrote: > > > I've read about the rusting cross beams, and saw the Cal 28 web site > > detailing the replacement of the rusted out beam. I have what might > > appear to be a dumb question. > > > > Instead of replacing the crossbeam with another steel beam that will > > eventually rot again, why not seat the mast support on some poured > > mortar? > > > > > > > > Rog Jones posted an explanation that I think I understand. He said > that the beam transfers forces such that the hull bears almost none of > them. Thinking this through, I'm assuming that the mast sits on the > beam, and that the shrouds' loads are carried down to the beam via > tension rods. Thus, the shrouds don't pull up on the hull via > chainplates, they pull up on the ends of the beam via tension rods. My understanding, and it has been a long time since I took statics, is that the structure is a triangle. Think of it as a bow and arrow. The mast presses on the beam and the tie rods that connect chain plates to the beam transfer the load of the shrouds. The mast is like an arrow that is pressing on the bow. The bowstrings are the tie rods plus the shrouds. There is no load on the hull. If the beam rusts out and the ends raise with the shroud load, the shrouds get too long on the loaded side and the mast leans away from the load. The result is a mast out of column and collapse. The bow and arrow concept applied to a conventional hull about the size of the Cal 40 that had the mast go through the bottom of the hull in a Bermuda Race. The hull was laid up in two halves that were then bonded together. The bond failed under load in the Gulf Stream. The Cal boats should never do that as long as the beam retains its integrity. Mortar would do no good as the load on the beam is not uniform. In the center it is compression but at the ends, it is tension from the shrouds. The load tries to bend the beam like a bow. Mortar would not handle the tension. The only compression is the center of the beam under the step and the deck between the chain plates and the mast. That load is probably small. It would be equivalent to another spreader. There is a guy on the Cal 40 list who sent me pictures of his failed beam. It came apart in his hands. It had rusted through on each side between the step and the tangs for the tie rods. I'll post the pictures. Mike Kennedy Conquest Cal 40 # 96

The mast is under compression (downward forces). The shrouds are under tension (pulling upwards). On the Cal 40 and the 3-30, the loads are transferred from the outboard ends of the beam through steel connections (big turnbuckles for the Cal 40 and steel yokes for the Cal 3-30). On the other boats, the beam is bolted to the bottom of the bulkhead. The chainplates are bolted to the top. So the main bulkhead is being pulled upwards at its ends, but can't move because it is anchored to the beam. The upward force is therefore transferred from the beam, through the bulkhead to the chainplates and then to the shrouds. Sooooo. the load goes down through the mast, across the beam and back up through either the connectors or the bulkheads and chainplates to the shrouds. The loads are thus balanced and equal, i.e., the downward force on the mast equals the lateral thrust on the beam plus the upward thrust on the shrouds. Voila! There is no force on the hull. These are equal force vectors and can be graphically calculated even by most eighth graders, today. That simplicity is what makes Bill's solution so elegant. Now, imagine no beam. The mast is pushing downward. The chainplates are clamped to the sides of the hull and the load is pulling upward on the shrouds. That would cause the hull to want to squeeze inward toward the center of the boat. You could offset this with a heavy beam under lateral compression at deck level, but the hull is still being pulled toward the top of the mast. So you would have to thicken up your hull to take the extra forces, adding huge amounts of weight. Brick mortar (dry) weighs about 137 pounds per cubic foot. If you were to fill the hull with it below the waterline, you'd be adding that weight, plus the weight of the deck level beam plus the weight of the additional laminate. My guess would be about a thousand pounds a boat, and all that to do what Bill did with his elegant little beam. \Rog Cal 29+ #1 Swiss Navy Cal 2-30 #77 St. Lori's Comet Mortar gets harder over time when exposed to water and would never rust. The steel part embedded in the motar would be high out of the water. The area appears to be a ready made mold for pouring. It would be heavier, I am sure. (I am doing a lot of mortar work around the house as I write this) I thank everyone for their comments to my main sail problems, and I am mentally prepared for any responses to the above inquiry. Gracias, Bruce Stirling Gangfurd Cal 28 - Hull 82 http://www.stirling <http://www.stirlinglaw.com/cal28> law.com/cal28 _____ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.394 / Virus Database: 268.9.0/368 - Release Date: 6/16/2006

--- In Ca… [at] yahoogroups.com, "mtkennedy1" <mtkennedy1@...> wrote: > > --- In Ca… [at] yahoogroups.com, Chris Campbell <clcampbell@> wrote: > > > > > > > > rua84 wrote: > > > > > I've read about the rusting cross beams, and saw the Cal 28 web site > > > detailing the replacement of the rusted out beam. I have what might > > > appear to be a dumb question. > I posted the photos of the Cal 40 beam here: http://pg.photos.yahoo.com/ph/mtkennedy1/album?.dir=/f6dcscd&urlhint=actn,del%3as, 1%3af,0 I don't have pics of the new beam but there are some around here of a Cal 29 beam project with the new beam. Mike Kennedy Conquest cal 40 # 96

You may want to consider poltruded RFP I BEAMS - they weight a lot less than steel with the same properties and no rusting Let me know if anybody want a link on it mtkennedy1 <mt… [at] cox.net> wrote: --- In Ca… [at] yahoogroups.com, "mtkennedy1" <mtkennedy1@...> wrote: > > --- In Ca… [at] yahoogroups.com, Chris Campbell <clcampbell@> wrote: > > > > > > > > rua84 wrote: > > > > > I've read about the rusting cross beams, and saw the Cal 28 web site > > > detailing the replacement of the rusted out beam. I have what might > > > appear to be a dumb question. > I posted the photos of the Cal 40 beam here: http://pg.photos.yahoo.com/ph/mtkennedy1/album?.dir=/f6dcscd&urlhint=actn,del%3as, 1%3af,0 I don't have pics of the new beam but there are some around here of a Cal 29 beam project with the new beam. Mike Kennedy Conquest cal 40 # 96 --------------------------------- Ring'em or ping'em. Make PC-to-phone calls as low as 1¢/min with Yahoo! Messenger with Voice.

--- In Ca… [at] yahoogroups.com, "Rog Jones" <rog@...> wrote: > > The mast is under compression (downward forces). > The shrouds are under tension (pulling upwards). > So, I think I understand a bit better. Thanks for the explanations. However, I think I read on this group that some of you like to race with your shrouds loosened a bit. Will loosening the shrouds thus increase the downward forces on the mast? If true, could the curvature in the ceiling of the boat (sorry, Chris, what was that ceiling called again?) I noticed be due simply to loose shrouds, instead of a rusting cross beam? Last time onboard, I pulled the bilge cover and stuck my head down there with a flashlight to look for evidence of rust and anything else I could see. There really wasn't much to see. Lots of fiberglass. I didn't see much else. No metal, anyway. Bruce Gangfurd Cal 28 - Hull 82 http://www.stirlinglaw.com/cal28

Rog Jones wrote: > The mast is under compression (downward forces). > > > > The shrouds are under tension (pulling upwards). > > > > > > > > Sooooo... the load goes down through the mast, across the beam and > back up through either the connectors or the bulkheads and chainplates > to the shrouds. The loads are thus balanced and equal, i.e., the > downward force on the mast equals the lateral thrust on the beam plus > the upward thrust on the shrouds. Voila! There is no force on the > hull. These are equal force vectors and can be graphically calculated > even by most eighth graders, today. That simplicity is what makes > Bill's solution so elegant. > It is elegant, but the picture is not so obvious in the case of deck-stepped masts as on the Cal 20. Here, there's a beam but it's wood (and, in the case of my boat, sistered to add strength). The beam there is primarily to provide the compression part of the equation--to keep the sides of the boat apart. The shrouds pull up on the hull/deck unit and the mast pushes down on the hull via the two compression posts under the deck beam. It actually works, at least after the deck beam was sistered. Which has always made me wonder of the teak sisters on that deck beam were a factory fix. They look like it--they are nicely formed and finished and do not have the owner-improvised look about them. You can usually tell. Does anybody know if Jensen Marine had a factory fix for cracking Cal 20 deck beams? Chris Campbell TC > > > <http://docs.yahoo.com/info/terms/> > <mailto:Ca… [at] yahoogroups.com?subject=Unsubscribe>

On Jun 19, 2006, at 9:09 AM, Chris Campbell wrote: > > > Rog Jones wrote: >> >> The mast is under compression (downward forces). >> >> >> The shrouds are under tension (pulling upwards). >> >> Sooooo… the load goes down through the mast, across the beam and >> back up through either the connectors or the bulkheads and >> chainplates to the shrouds. The loads are thus balanced and equal, >> i.e., the downward force on the mast equals the lateral thrust on >> the beam plus the upward thrust on the shrouds. Voila! There is no >> force on the hull. These are equal force vectors and can be >> graphically calculated even by most eighth graders, today. That >> simplicity is what makes Bill’s solution so elegant. > > > > And the integrity of the beam so important. Mike Kennedy Conquest Cal 40 # 96 > . > >

The Cal 28 does not have a steel cross beam. The structure is more like the Cal 25 except there is a single continuous connection of a compression post to bulkhead and floor pan to a wood block sitting on the hull right at the beginning of the keel which is the thickest lay-up in the hull. It appears to me the whole main bulkhead and post make up what is refered to as the "triangle" structure in this tread. As for mortar, I think not. For one thing any structure like the steel beam or wood beams in the 25 and 28 are floating on fiberglass tabbing to prevent hard spots and allowing the hull to flex some so the hull doesn't crack. Richard --- In Ca… [at] yahoogroups.com, "rua84" <bruce@...> wrote: > > I've read about the rusting cross beams, and saw the Cal 28 web site > detailing the replacement of the rusted out beam. I have what might > appear to be a dumb question. > > Instead of replacing the crossbeam with another steel beam that will > eventually rot again, why not seat the mast support on some poured > mortar? Mortar gets harder over time when exposed to water and would > never rust. The steel part embedded in the motar would be high out of > the water. The area appears to be a ready made mold for pouring. It > would be heavier, I am sure. > > (I am doing a lot of mortar work around the house as I write this) > > I thank everyone for their comments to my main sail problems, and I am > mentally prepared for any responses to the above inquiry. > > Gracias, > > Bruce Stirling > Gangfurd > Cal 28 - Hull 82 > http://www.stirlinglaw.com/cal28 >