A Photo & Discussion Forum for Wharram Design Enthusiasts
After a summer of sea trials and preparations, we (my wife Kathleen and I) left Hornby Island BC on Sept.14 bound for San Diego using the offshore route. If only we had left a week earlier while the weather systems were more or less normal, we could have avoided all the unseasonally heavy weather that caused us to go inshore and seek shelter when needed in whatever port was nearest. The weather has been dreadful; 4 days of storm force winds and 7 at gale force. Even when winds were forecast at N. 5-15 we found ourselves in a whole gale (maybe more, we don't have wind instruments) rounding Cape Blanco at night and doing 8-9 knots under bare poles. Right now we are in Humboldt Bay, California, waiting for a weather window for rounding Cape Mendocino. Kattu has performed well under heavy going but for one unsettling issue...the movement and thumping noise of the rear beam. I have 8 turns of lashing on the insides instead of the six called for in the plans, as I had read of this problem in one of the older forums. All of the lashings have been re-tightened twice now, and there still is some movement. Off Cape Blanco I could have stuck a finger between the beam and it's rubber pad at times. I would sure like to hear from others with offshore experience whether this is just a normal situation for a Tiki 38 or do I need to add even more turns of lashing.
@Hans: What is the issue with spectra rope vs. "regular" polyester brais rope? Does your comment also allpy for Dynema and other Kevlar/Aramid-related fibres? Is it the low stretch ability?
I am just curious abour your opinion.
Thanks and regards and always fair winds
The spectra (Dyneema) is a VERY low stretch line. It is difficult to get it tight enough to stay tight. The good poly double braid has enough stretch that you can tighten it up into its' stretch zone with the frapping turns. prefer to use spectra for the frapping turns as it is very slippery and does not stretch much. If the spectra does not have enough load on it it will creep and slack. It needs to be tensioned enough to settle in. This is what John Franta of Colligo Marine told me.If your poly lashings are stretching thin I would assume either porr quality line or too small a diameter. We use a truck too tension the spectra frapping turns while applying dish soap and working the frapping turns with levers to avoid any slack spots in the frapping turns. We set our boats up tight. This means that our rigs stays tight and there is very little movement at the beam blocks. We use a 1/16" thick reinforced neoprene pad between the beams and blocks. The beams and blocks are pressed very tightly together and without the pad when the beam/block interface moves minutely the noise is horrendous. The pad eliminates that noise.
After about three years in the Chesapeake, our aft beam inside lashings started to make some noise, but I have not seen any movement or wearing on the pin. We now have another three years on the same lashings, and have made one Gulf Steam crossing in fairly benign conditions with no change. We still have the original lashing lines (I think 3/8 inch dacron double braid) which were tightened ashore using a 2X4 lever with a lot of weight behind it. The lashings were all very tight (all the initial construction twist was pulled out) and I put five and six turns on the port and starboard inner lashings, respectively. I know the boat changes shape from the way the rig behaves, but haven't subjected the boat to heavy ocean stress. The Bay has a very short steep chop which causes a lot of wracking movement, particularly upwind, but haven't seen much movement on the aft beam, although it does make some noise. No conclusion here, just a data point.
I do have one pin, the port pin on the 2 beam, which will no longer go through the beam. I can't figure out how it moved when the other pins are all in, but so far has not been a problem. I also can't figure out how to fix it.
Ron , we experienced the same problem in our Tiki 38, one of the pins carved its way from its original hole. the gasket was made in delrin but i dont know if we should make it in bronze ( galvanic currents??). we sailed that way more than 4000 NM and we had no problems regarding structural safety on our boat, we obeserved some movement on the beam at that point though
I have delrin rings in the beamtroughs, with a double layer of glass in the beams where the pins go through. The pins were out when the beam apparently moved (about a millimeter or two) and now it won;'t go back. It was always a little tight, so I guess I'm not surprised that it's out of position. We got bounced around quite a bit in the last schooner race when the pins were out (don't ask), but I'm puzzled that the other two pins on that side are in place and this one is not. We are sailing the boat, and so far it hasn't seem to make any difference. The 46 uses a different system, and maybe that would be better. I don't think bronze would be better, it would just push the failure somewhere else. The 38 is maybe not quite big enough for four beams, but too big for three. I've always wished that Wharram had designed a Tiki 42, but understand the problems. Going to additional lashings on the aft beam, and monitoring their health seems like a sensible thing to do. And so far, no one has had any real problem with the configuration. Really tight lashings seem to solve most of the problems. I also put oversize quarter inch nylon pads under each of the beams to protect the softwood, so that is probably why we don't get too much noise.
I promised an update on the beam lashing issue after crossing the Pacific, so here it is! The dyneema performed so much better than the double braid had, staying tight in spite of high winds and huge seas. We are now in Tahiti, after visiting the Marquesas and Tuamotu having sailed from the Pacific coast of Mexico. During the worst weather, hove to in a gale, there was no noticeable movement at the lashings, and no sounds at all from the lashings or the beams. We continue to regularly run into unusually rough weather....a near gale leaving the Marquesas, and then a tropical depression inside the Tuamotu, with no sea room to run even with a drogue. That was unpleasant. But at least the boat always felt secure with the dyneema lashings holding her well together. The Dyneema has shown no tendency to cut into the beams, and cinching the lashings tight with the frapping turns has been sufficient. Maybe the dyneema doesn't have to be so tight since it doesn't stretch! A bit more than snug seems all that is needed. I will eventually replace all of the lashings with dyneema based on what I've experienced so far. I must say that the Tiki 38 has proven to be a very capable, seaworthy cruiser, after working out a few bugs!
Yes, I doubled the inner lashings even though that may seem like overkill. I wanted backup in case a brummel splice failed. It was a newly learned skill and I wasn't sure I had it right, but in fact all of the splices I made turned out to be good. The Dyneema is slippery and does involve a learning curve, but the doubled lashings did not cause any chafe or other problems, so there's no harm to them being there even if they are not really needed. I used 8 mm out of concern that a smaller diameter would cut into the beam. The Dyneema actually spreads out almost flat where it goes around the top edges of the beams so the load is nicely spread out. My beams have a 1 1/2" radius at the top edges; this also helps spread the load. If you think about it, the best shape for the tops of the beams would be a hemisphere which would pretty well eliminate any tendency of the lashing to cut into the beams.
I hope you are having success solving your beam troubles; what a horror story!
Thanks Alf, aft beams is fixed and everything is back in operation now! Good luck with the trip!