I've built new I-beam style crossbeams for my Pahi31 which were drawn up
by JWD. My old beams are bolted in the center of the trough and lashed
at the ends. I would prefer to do away with the bolts (leak points)
and just lash similar to other designs but I can't come up with a good
way to lock the sideways movement of the beams.
Any suggestions or ideas for beam attachments/lashings? I see in capgeraldo's comment on the "mast shrouds" discussion that JWD offers two attachment methods for the Pahi42, one with bolt and lashings, like my 31, or lashings only, which I would prefer. Can anyone describe what JWD has drawen for the lashing only method on the 42 and could it apply to the 31?
On my 38 (which has the same type beams) i glassed the inside of the hole. Make it slightly oversize, wet it well first with thin epoxy, then with slightly thickened epoxy, wet out the glass, roll it into a tube smaller than the hole on a taped dowel, and sort of walk it onto the hole sides by rollling it off the dowel. Round the ends so the glass ends can be expanded to cover the glass on the beams. Make up a couple pieces of glass because some will not behave, and you will ruin them. I know it's not the solution you were looking for, but it works.
I also talked to Hanneke about using vertical wood bars at either end of the beam- Two fit on the hull and one fits on the beam between them to lock the beam in place while still allowing for some vertical movement. THere are two sets (one on each side of the beam0 near each beam attachment point, for a total of eight sets per beam. Ultimately I went with the pins because I thought lining up the bars (and getting them the right depth for each beam, as the beams do not lay square in the troughs) was just going to be too difiicult.
I think you're right about using the pin/bolt method being the simplest as for as lining up the beams. Yes it would be quite complicated to get those vertical bars in the right place. Since I already have the beam pockets reinforced for bolts I should probably stick with them. I like the idea of completely isolating the bolt in a reinforced tube. I wonder If using a G-10 tube and epoxying that into the oversize hole might be a little easier.
My existing beams have, from the earliest Pahi version, just 3/4" bolts straight through both the bulkhead and beam with no vertical adjustment possible. The new beam plans Hanneke sent me use an oblong hole in the beam, to allow for vertical movement, and a pin instead of a bolt. The bulkhead hole is covered, after the pin is in place, with a gasketed wood cap, theoretically keeping water out. Do your beams have this oblong hole for vertical adjustment?
I've already spent too much time building these new beams. Just keeping the center bolt/pin attachment is the quickest to get me back in the water.
Great drawings! This way is even better, solves the alignment and height adjustment, gets rid of the potential water leakage, and other than plugging my existing bulkhead holes and fitting blocks is probably easier than reinforcing the existing holes. I don't have any holes drilled in the new beams yet, so it's easy to adapt this method.
Both you and Ron have given me great ideas. I've got another week of painting the new beams then weather permitting I've got to disassemble the boat then separate the two hulls hulls. I'm widening to the newer Pahi overall width of 16', the first Pahi31's were 14'. I had already rigged with the wingsail so I'm getting rid of the old cutter rig mast beam and Hanneke figured I could eliminate the number 3 beam also (James apparently said the original 31 was "overbeamed"). This will make my cockpit huge and uncluttered compared to the original. The new designed beams are lighter than the originals even though they're longer, and since I'm eliminating 1 full length and 1 half length beam I'm loosing quite a bit of weight probably close to 130-140 lbs.
On the plans for the Tiki 46, there are the pads to center the beam in the trough as in the second illustration but the fore and aft pads attached to the vertical sides of the trough are smaller than your illustration on Peace and near to the top of the trough and there are holes in the wooden pad that the beam sits on so any water that gets trapped inside the trough can run out. This has proven useful for us and I often wish we had made the holes a bit larger because sometimes when we are anchored close to shore, leaves etc can get in there and block the hole. I just clear them with an old nylon wire tie which works well, but sometimes quite a lot of water comes out when the hole is finally cleared. My worry that flying fish would fall in there and fester has not happened.
We have pins to center the beam so the hulls stay together and do not slide away from each other. These pins go through a vertically elongated hole in the beam and that part of the beam where the hole goes through is full thickness while the rest of the beam is the I beam shape. These elongated holes were coated carefully with thickened epoxy to prevent chafe. The tight beam lashings keep the beams from moving too far up and down. Where the pin goes through the trough sides, we made a fiberglass bushing by wrapping a pin with polyfilm, and then with wetted out fiberglass which we rolled onto the pin and let it go off. When it was hard, we slid the pin out of the long fiberglass tube (with some difficulty as I remember) and chopped it into lengths which we glued into the beam trough so the hole in the trough is quite well protected from damage due to stress on the pin. When we glued these fiberglass bushings into the troughs, we did it with the pins temporarily in place so it all lined up ok. We made extra large covers over the pin hole on the interior of the boat and used sealant when we screwed the covers on and there has never been any leakage which is good because those troughs go right over the beds! We inspected one recently and there was no damage of any kind.
I will admit to feeling less than full trust while we were building the boat. I feared the worst about leaks, damage, and all kinds of nightmares. In fact, we have had no trouble at all. I saw that Jacques Tiki 38 has the same system we have on the Tiki 46 so it is well tested by now. I do think the blocks in your first illustration will work out and they are similar to what we put on Peace to center our center short beam that goes at the forward end of the deck pod. We also put pads similar to what you illustrate to center the forward mast case, deck pod, and a few other things. But nothing seems to have moved so I don't know if our pads were needed or not. They are reassuring though.
The material we used for the base pads that the beams rest on was hardwood but the material we used for the side pads was nylon pads about 2 inch by 4 inch on the beams rubbing on stainless sheet that Nev dimpled and set in place on the trough using countersunk screws. Again, no damage. Our plans called for hardwood there, but we had the free nylon and stainless lying around so we used it and bedded it in.
In severe weather conditions, we do have a squeak at the starboard end of the beam that crosses aft of the cockpit. This can be quieted with a pail of sea water, but it attracts curious whales so we let it squeak and they have never harmed us. We had whale visitors most days on our trans Atlantic. Waves need to be about 5 or 6 feet for it to squeak, but there is lots of that way out there. They were really curious and came right up there sniffing around, swimming right under the boat, and examining both hulls but were mostly interested in that starboard beam end and after a long examination, they would leave us. They were often 10 feet from the boat swimming along like dolphins do. They were right whales, sei whales, and some others we looked up at the time, but I misremember now. The first curious whale was unsettling, but after that we just enjoyed their company. When we got to Martinique, Bertran Fercot put a flip flop wedged near that squeak and now it squeaks less often. We love Bertran so much, we left that flip flop in place to remember him.
Ann and Nev
The hole on the 38 is also oblong. I haven't observed any movement of the beams, but we worked very hard to get all the construction stress out of the lashings. After two and a half years of fairly hard sailing in Chesapeke chop, the starboard inside lashing on the 3 (aftmost) beam has developed a creak, more like a great blue heron than a whale, but it hasn't moved at all, and so far has not attracted any visitors. Like Ann, I was worried about mavement of the beams and leaks developing in the troughs, but it just doesn;t seem to happen. The last winter the boat was ashore with the beams in place, one of the holes in the hardwood pads under the beams filled with leaf dreck, and in the spring I had a two inch mushroom growing out of the hole. Fortunately only in the leaf mold iself; the beam and the hole in the pad were untouched, and cleaned right up. So I think there is quite a bit of overkill built into the system if you are careful in building and follow the plans. I made bushings for the pins in the hulls using solid delrin tubes drilled out for the pin. These were difficult to align in the beam troughs (we glued them in with the beam in place) but seem very secure. I tried building up bearings, but unlike Ann and Neville, had real difficult getting them off the form and gave up for the drilled out tubes.
I'm glad to hear that the pin centering arrangement and sealed caps over the pin holes has been trouble free and tested on both the 38 and 46, so it's probably more than adequate for my 31 but it has always troubled me that all those stresses of beam sideways movement are concentrated on just that small pin and bulkhead/trough reinforcement around the pin. Of course the lashings contribute, maybe I'm just overly paranoid.
I too have had beam pocket squeaking but no whale visits associated with squeak. In dead calm I've had gray whales come under the boat. Decades ago in a 10' dingy an Orca in dense fog with not a ripple on the water surfaced very slowly about 3 feet away, checked us out for a couple minutes rolling his big softball sized eyeball making direct eye contact, then slowly submerged with not the slightest splash or movement. I had 3 of my boys with me (10, 6, 3 yrs old) and I know that Orca checked us out and seemed to communicate that he wasn't there to harm us. It was kind of like a peace offering, I'll never forget it! And, even though I was scared to death I know there was some level of communication with that Orca, maybe he/she sensed my fear and somehow purposely put me at ease. Every time I see Orcas, we have several pods visiting here in Puget Sound, I recall that encounter and have incredible awe of their species.
Thanks for sharing that feeling of peace you felt when the orca came close to your dinghy. We also felt that most of the time. Of course I have no idea what Peace was "saying" to the whales when she squeaked that way, so I was mostly hopeful it was not something rude! I felt the visiting whales were concerned about Peace, but eventually figured out that she was ok. Many years before, when I was alone crossing the Atlantic in a small monohull, a very big dark colored whale twice the size of my little 28 footer, came right alongside for about an hour and I had a distinct feeling of peace and wellbeing as the large creature kept pace. It was a sperm whale I later discovered. A wonderful thing to be so close and feel that communication. Ann