MultiThom

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About MultiThom

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    Super Anarchist
  • Birthday 07/10/1950

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    https://groups.google.com/forum/#!forum/searail-19-trimaran
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  • Location
    Benicia, CA
  • Interests
    Trimaran sailing; sailmaking; boat rigging; SeaRail 19 Trimaran Google Group

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  1. MultiThom

    Multihull speed vs length

    What happened on my F242 is when we're powered up with kite, I'm all the way back in the stern holding onto the mainsheet since the main controls the heel mostly and can keep you safe until the wind is so big that the main has no impact on heel, then you have to rely on the spin sheet crew to release that sheet to keep you from a pitchpole in a gust. That crew is also aft and outboard and the sheet is wrapped around both winches to give grip but not in the self tailer. The boat, fore-aft, is then bow up...which also means the aft leeward ama is submerged (like you can see in the photo above). The outboard beam typically hits before the strut. Trouble is, the gusts usually drive the bows down as well so you just stop and the stern pops up. If everything is released, you plop back down, clean your shorts and start sailing again. One of the reasons I got rid of the cam cleat on the mainsheet in favor of a spinlock was the fact that if you are really loaded up (wimpy mainsheet cascade on stock F242 was only 5:1--8:1 was much better), you can't unload the mainsheet quickly. Had water at the mast base on the main hull that time. About fat foils...I don't think that was much of a factor since most of the time on my boat I had the daggerboard lifted when going downwind with kite.
  2. MultiThom

    Multihull speed vs length

    It is mostly drag based on my F242 experience. The drag is from beam and folding system appendages getting into the water. Back in 2012 I posted a video of my boat going through the finish line with 4 people on board at 19 kts (actual sail was in 2004). Gust hit at the finish line and you could get a good view of what was the drag. Unfortunately, that video is blocked by YouTube because of the music I used in it. If you aren't in the USA you might still be able to view it, title is "Best of Puppeteer".
  3. MultiThom

    Multihull speed vs length

    I favor the aussie texel version for base speed to compare boats across platforms. I don't bother with all the add ons and political crap that got added in for racers (where you have to measure all the sails at different spots along the luff, and how much the rotating mast length is, and ....). You can use published numbers although you should realize that the published weights are most often wrong by up to 25%. OMR and Multi2000 prefer to use a TCF, a time correction factor, so their basic formula is even simpler: TCF = rl ^0.3 * rsa ^ 0.4 / rw ^ 0.325. Basically a dimensionless number length to the 0.3 time sail area to the 0.4 all divided by the weight to the 0.325. Gives a good comparison. But it doesn't account for lots of things like chop if you sail in it routinely or course selection if you are always on a reach--also doesn't account for pointing ability, some boats don't point worth a damn while others point like champs. You should just use the upwind sail area since you spend more time going to weather than downwind. If you want to add in the downwind kite, I think the rule of thumb is to use 15% of the kite area. You should also add crew weight for your normal crew size--can even use it to estimate how much slower you will be with an additional body on board. http://www.texelrating.org/site/pub/Pagina.php?paginaid=81
  4. This is all true. I did lash out at James, James and Paul--after months of wrangling. I really can afford to pay for my own repairs but only wanted them to step up and accept responsibility. Y'see, the only thing left out of the explanation is the root cause...Triac moved locations and in so doing, lost part of the daggerboard trunk mould. Which they remade, but made wrong...so the boat halves would not go together as designed. So during final assembly, some bozo decided to bash it to fit. In the worst possible place. Someone was more interested in production schedule than quality product (sounds like the Rapido's now, right?). And, no knowledgeable oversight over production during a critical evolution. They did this to every one of the boats in that production run. Prior searails don't have this issue since they were made with original moulds. I wouldn't own a dog bowl made from triac.
  5. MultiThom

    Multihull speed vs length

    I thought a seacart was as well.
  6. The only reason I HAVE a vendetta or venom is because triac corporation made a shoddy product. Thought it is something somebody should know before plopping half million dollars or more down on a vessel that their lives depend on. IF I ruin someone's reading pleasure with my "Manky" construction (as Russell called it), too bad but unlike most fake news, this is actual shoddy construction with evidence of the same for everyone to see.
  7. MultiThom

    Multihull speed vs length

    Yah, not sure I believe him. He's exaggerated before and hasn't shown any gps tracks.
  8. Thanks. That is one thing that makes sense from you. Koch has been making tris forever it seems; he grudgingly agreed to warranty repair of my F242 last century but didn't stand behind the work on my searail; what changed? Where is the 60 that was being made at the same time as the shoddy work done on my boat in 2017? That might give a better view of the quality of the new rapido's than my biased albeit video backed, warning.
  9. Why do you buy anything? You trust that the guys who built it know what they are doing...which is the gist of my warning...I misplaced my trust to the tune of 30K...knowing this, what would you risk for something built by the same folks? And yah, the inside looks pretty bad, but I didn't look there until I had leaks I couldn't explain. Who would expect a boat builder of trimarans to bash together a daggerboard trunk made (supposedly) with mating moulds? The design of my boat is good, the execution is not great. I've experience enough with boats to fix most anything, so I took the risk. I also don't go offshore anymore, so I can swim back home if I have to.
  10. MultiThom

    Multihull speed vs length

    I've noted that the differences in top end speed for a non foiling trimaran is a length dependent function. That is, you can push a trimaran of 24ft to say 22 kts. The longer the trimaran, the faster the top end is, but in no instance have I ever seen a non foiling trimaran go faster in kts than its length in feet. Might have happened, just never have seen it documented. OTOH, non foiling catamarans seem to be able to go faster than that at their top ends...for example, an 18 ft catamaran beach cat can exceed 18 kts of boatspeed. This is just based on observations over the years in videos and personal experiences. Note that the top end speeds have little to do with boat ratings in general. Which is OK since in practice, most races are done in sensible conditions and courses. Boat ratings are an exercise in politics and observations plus some glittering mathematical explanations after the fact.
  11. here is a link to a video posted on YouTube showing the boroscope inspection. https://www.youtube.com/watch?v=NPjOvU-3mHs Just to be clear, Rapido "may" be stationing inspectors at triac to avoid the manufacturing errors which occurred with my searail--I hope they do for their reputations' sake. The ongoing discussion about production schedules and pressures frankly give me the willies since those same forces were the impetus for the errors in my boat. My purpose in this post is merely a warning that past boats built by triac for a manufacturer have had defects--as in any crap shoot, past performance cannot be used to predict future rolls of the dice. I took a 30K risk which is not a big deal to me and I still enjoy the boat but it has been a long time getting the errors fixed.
  12. Can't post the pictures since I fixed the void issues a couple years ago.  here is a link to a video posted on YouTube showing the boroscope inspection. https://www.youtube.com/watch?v=NPjOvU-3mHs This is a searail 19, searail being the manufacturer of record.  Hulls manufactured by triac.  Boat manufactured in 2017 and triac still owned by same persons as far as I know.  Just to be clear, Rapido "may" be stationing inspectors at triac to avoid the manufacturing errors which occurred with my searail--I hope they do for their reputations' sake.    

  13. Since this seems to be a running unpaid advertisement I just want to reiterate that my boat was manufactured by this company (triacComposites). The workmanship is shoddy (voids) and the finish is very poor (take a look with a boroscope in any non living spaces). Significant manufacturing errors were made by triac and triac company made only half hearted effort to correct their errors stating that legally they had no responsibility to the end consumer and that the manufacturer of record was the legal entity to whom I should look for redress. While legally, this is true; but wouldn't you expect the entity who makes the error to feel responsible? Consider this as negative feedback for triac composites company.
  14. MultiThom

    boomless mainsail reefing

    For the boomless mains that I've used, the foot length is only shorter by an inch or so while the leach length is pretty much 5 feet shorter (for the first and only reef point on the mains I've owned). Basically, the sail area reduction is pretty much a rectangle, not a trapezoid. The result is typically a firmer leach for the smaller sail.
  15. MultiThom

    boomless mainsail reefing

    Thinking back to my "jiffy reefing" slab reef system on my old F24, it was nice that the leach could be pulled down from the front of the boom by a line that was led back through a sheave, up through the reef grommet in the leach and back down to the boom and then cleated at the front of the boom. IF I change to the F25C system with a rope clutch built into the main next to the clew grommet, I could add a turning block somewhere so I could lower the mainsail from in front as well as pull down the leach from in front. Might give that a try.