Joakim

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About Joakim

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  1. If you can, why not input heel and pitch from your new compass to NEXUS bus? That would take care of the heel compensation you have lost. I really liked the Nexus system I had on my previous boat and I did my own system to add targets and store all the instrument data without using a computer (I used NSLU2, a bit similar project to Raspberry Pi). There may be a problem using your MHU with B&G, but I don't think leaving the old displays at the mast is a problem, if you do change the processor. I have NMEA0183 displays at the mast and even they work just fine for showing BSP etc, if you feed the data at a decent update rate.
  2. Joakim

    Beneteau dropped the First line?

    Delphia makes bigger yachts as well (40.3 and 47 at the moment) and Maxi only bigger ones in Poland and they are know to be cheap. Seascape has been clearly more expensive than older First models. The specs file has "light" in it. I wonder will there be a non-light model that is cheaper. Also the light model may have modifications that make them cheaper to make. Hanse has also bought a lot of boat yards and then they have made them cheaper (Dehler, Moody etc) and taken over the production to their site. E.g. Dehler 34 SV -> Dehler 35 had a lot of small modifications to make it cheaper.
  3. Joakim

    Beneteau dropped the First line?

    Specs seem to be exactly the same as for Seascape 27 it used to be: https://www.thinkseascape.com/boat/seascape-27/vikings-on-holidays/#technical-data But did they make the construction cheaper? They don't mention e.g. "carbon fibre beams laminated to keel box and glued to the deck to support mast compression and hydraulic ram that operates the keel" you can find in the Seascape data. Seascape sold quite well for a new brand. Did the prices go down when their models were renamed First?
  4. Joakim

    Masthead vs Frac Assym

    That's true only for upwind sailing or close to it and is mostly due to induced drag. Downwind sailing it is the other way around and drag becomes your friend when AWA>90, but compensated by vertical wind profile giving higher wind speed at higher location. Usually having masthead kite means bigger area, but OP defined masthead to have a shorter prod. With about equal area the question is far from a straight forward answer.
  5. Joakim

    Rod Rigging Tension Gauge for 11mm rod shroud

    First 45 has about 300 kgm/deg RM. At 30 deg heel + crew that is about 9000 kgm. The chainplate is probably about 1.3 m from centerline. So the static load on the chainplate is about 7 tonne at 30 deg heel + crew. That is mostly carried by V1. 13 600 BL sounds just OK. For my boat a similar calculation gives chainplate load of 55% of V1 BL. For First 45 it was about 50%. For -16 that would be 95% and it would certainly fail in dynamic loads. It actually sounds so similar to my boat, that you may also need over 25% BL pretension.
  6. Joakim

    Rod Rigging Tension Gauge for 11mm rod shroud

    What would be your use of the tension gauge? I have never really needed one. I use the 2m ruler method and measure also the turnbuckles (the travel distance and the final position). For each season I put the turnbuckles to the same position I found to be good six years ago. I have used the ruler method a few times since and found no difference in the tension with the same turnbuckle distance. Also a rig simulation was done to my boat. It suggested that 48 mm travel is needed for the V1 turnbuckles to reach enough tension to keep leeward V1 in tension at "full power". I had used 45 mm without knowing about this. In my boat the 2 m ruler method gives about 2/3 of what turnbuckle travel/distance to forestay would give. Thus about 1/3 is due to forestay stretch or hull flex. The rig simulation includes forestay stretch but not hull flex, which is likely quite minimal in my case. For my boat Selden/Yard has chosen quite small size rods. Thus I need to have more than 25% of BL as pretension. V1 BL is about equal to the displacement of the boat. First 45 has about 11 tonne displacement and has a rather narrow chainplate distance, thus 13 600 BL is not so surprising.
  7. Joakim

    Dynex Dux Longevity

    The data on page 12 shows that 8 mm dyneema looses 40-60% of its strength in a few years of UV exposure: https://issuu.com/eurofibers/docs/name8f0d44 Note that it is not at all linear as Colligo's chart suggests.
  8. Joakim

    gyro autopilot compas heading

    It also solves the problem I brought up, since the target AWA is high it will not pinch to normal AWA unless the target boat speed is already reached. To me this sounds more like target boat speed steering and AWA is only used to limit steering too low when target boat speed can't be reached for some reason at normal AWA range. Why wouldn't the AP steer the same way downwind? Target boat speed and minimum AWA or TWA would work quite well I would guess. Which AP brands and models have these features?
  9. Joakim

    gyro autopilot compas heading

    Raymarine Evo models have a 3D gyro/accelerometer/magnetometer, but as far as I know it does not steer with constant heel. It may use heel etc. to help stabilize steering, but that is another matter. These sensors are very cheap nowadays (just as cheap as a 1D magnetometer), but it's another thing to use it to its full potential. That would require quite a lot of software development and testing on water. What I'm referring to is an AP that would take a target heel angle on a beat. So it would steer a bit higher with too much heel and a bit lower with too little heel, but still use AWA/TWA to keep the boat on a beat.
  10. Joakim

    gyro autopilot compas heading

    Steering to upwind by AWA is also problematic. If your speed gets way too low e.g. due to hitting a bad wave, after a tack or after a lull it takes very long to accelerate to target speed. If the boat has no speed AWA and TWA are the same. Say your target AWA is 25 deg and TWA 40 deg. At low speed the AP (or driver looking just at AWA) would steer at ~30 deg TWA resulting in very low BSP. While it should steer even lower than 40 deg TWA in order to accelerate rapidly to target speed. Do any of the modern autopilots use heeling angle for steering? That would probably be very good upwind.
  11. Joakim

    Beneteau dropped the First line?

    What's special aboat First Carbon versions? Carbon mast has been an option from the start of the 35/40 production. Carbon 35 seems to be with the bulbless keel, which was not an option during first years, but has been offered many years before Carbon version. We have three First 35's racing here. One is with the bulbless deep keel and carbon mast, thus probably the same as Carbon. It's keel has been replaced to this version several years ago. Not much of a difference to the original bulb version. The performance is not far from First 36.7, X-362 Sport, Dehler 34/35 SV, Dehler 36 JV or Bavaria 35 Match.
  12. How would scenario develop? If you have higher VMG, you get overlap at some point before the collision would happen. Only after that point does the other boat need to keep clear and you need to give her space and time to keep clear. After the overlap begins she needs to keep clear. She doesn't need to do anything before that and even after that she needs to really do something only when you are starting to be close. It is likely enough for her to change course to about the same course as you have and then the overlap is broken. If the overlap is not broken, you are trapped under them. So you would need to change your course in such a way that she will never need to take actions or at least so that the overlap breaks and then you can roll over her. The other option is that you have about equal VMG or she has higher VMG. Then overlap could form the other way around. Still she doesn't need to take actions before you are rather close. If you break the overlap soon enough, she has not broken any rule. In the "tack or cross" situation the port boat doesn't really have any keeping clear option anymore when she starts to cross. She can no longer tack nor cross unless starboard is kind enough to let her do that. I think that the starboard boat needs to start the duck so early that once port can no longer tack starboard can already keep her course. I would say that "sail her course" in the definition of "keep clear" is equal to "keep her course". There is no requirement for anticipation and there is a rule for ROW changing course (16). Thus port is keeping clear, if starboard can keep her course. If starboard changes her course, she needs to keep port room to keep clear and then port needs to keep clear from starboards new course. So once port is in a situation that there would be a collision no matter what she did if starboard kept her course, port has broken rule 10. A normal rather late duck of starboard most likely causes port a DSQ, if there is a protest hearing and all are saying how the things were. e.g. I waved her through and then started to duck about 2 boat lengths before, I would have hit her about 1/3 boat length from stern I have had not changed course. Or I waived her through and thought I wouldn't need to change course, but I had to make a small duck about 1 boat length before. Had I kept my course I would have hit her stern or at least been too close to hitting her. Since waiving and hailing has no meaning in the rules the starboard must allow the port to cross within the definition of keep clear. I think the only way to do that is that at any point port could keep clear by tacking or continuing, if starboard kept her course.
  13. Joakim

    Genoa question

    It is impossible to say. Define "competitive in club racing"? There are very different level of fleets and goals. By Pentex you likely mean a laminated sail. Does it have taffeta? On both sides? Someone would say a sail with taffeta is not competitive even as new due to added weight and stiffness, but it certainly does last much longer. My cruising sails are laminated polyester (Pentex is high modulus polyester) with taffeta on both sides. The jib is not that good, the form has been weird all the time I had it (since 2011), but the mainsail is still good enough for some level of club racing. The sails are from 2005 and have been sailed 13 000 nm (or maybe 10-11 000 due to miles sailed with my racing sails). I have won races with that mainsail and a different jib (racing jib or my 2008 cruising jib, also polyester laminate and not much used since 2012). Then my racing sails are aramid 3DL, no taffeta, from 2008. They were not used 2010 and 2011. I bought them second hand for season 2012 and payed 1/6 of the price as new + modifications needed (the sails were from another boat type). One of the three jibs (H/M) needed big repears already during the 2012 season and was never good (this was visible and I paid only 1/10 of the price as new). It is still usable, but no good for racing. The other two jibs were really good 2012-2014, but then the L/M jib started to be rather used. Partly due to lack of H/M. Heavy jib is still probably OK, since it is not used that often here. Mainsail is still fast, but needs a lot of small repairs to keep it in one piece. None of the other upwind sails have needed bigger repairs, only more and more insignia tape. I have raced only 2-3 races/year 2016 and after that. 2012-2015 I raced about 20 races in a season.
  14. That's a quite different story and starboard was restricted by rule 16. In normal case with hails starboard would keep its course and then duck, if necessary. That leaves the case open for the starboard or a third party to protest. I can see that port could easily get DSQ on rule 10, but starboard did not break any rule. In most cases port can't do anything at the point she notices that starboard is not willing to duck and thus has to start the cross confident that starboard will duck and doesn't protest. Starboard making a protest will not gain more friends and the next time port will leebow without asking, but still I find it hard to see this as a rule 2 case.
  15. Usually a starboard boat would like a port boat to cross instead of tack when the port boat can almost cross anyway and thus cause a harming leebow. It would need to change it's course quite early in order to make sure that port boat can cross without a fear of protest in absence of hails. That's not a good option for starboard, since port can tack anyway and starboard has lost height to windward. It may even be that the port could have crossed without any course from starboard. If a port boat is not even close to crossing, she will not be able to make a leebow either (depends on a class and conditions). Then you can just ignore her and roll her if she decides to tack.