dcnblues

Members
  • Content Count

    130
  • Joined

  • Last visited

Community Reputation

20 Suckup

About dcnblues

  • Rank
    Member

Profile Information

  • Location
    SF bay area
  • Interests
    Cats (Gunboat), tri's (Rapido 50)

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. dcnblues

    Gunboat 68

    No need to be pedantic, I assume you're well aware it's a figure of speech due to weather moving faster than most marine traffic. The dissipaters look sensible to me, but rather than a small permanent one I'd almost rather have a larger one you could haul up to the top of the mast when the situation called for it. And wait a second: Going from an insulating construction material (fiberglass) to a conducting one (carbon fiber) is actually better. The hull becomes a rather large ground, which is better. (I do imagine the carbon wheel [and carbon tiller(s)] would be insulated from the hull and mast, right?) + electrical (insulation) from your conductive hull. So it's probably going too far to call the bridgedeck a faraday cage, but it might share a lot of the protective properties. Be nice to not worry about the wheel, but I'm guessing that's an easy fix. So actually, now I'm guessing a carbon boat would do better statistically than those built from non-conductive materials...
  2. dcnblues

    Gunboat 68

    -Back to practical matters, I'm under the impression that the science of preventing lightning strikes is not well understood. That if you ask ten different electricians / electrical engineers, you'll get ten different answers. So this topic might bounce all over the place, but I'd like to see if I learn anything new either practically or conceptually. One buys a five million dollar boat made of conductive material, and sails out into a lightning storm: What's been done to mitigate the odds of a lightning strike? Does the paint insulate the hull from being conductive? What's the typical insulator between carbon and deck / mast hardware? Engine mounts? Glass? Are there any Gunboat stories where the electricals needed different techniques than conventional cats? Any info most welcome.
  3. dcnblues

    Gunboat 68

    That's what she said, right after crunching the numbers on the modulus of elasticity.
  4. dcnblues

    Gunboat 68

    This vid talks about the quiet advantages of a mixed glass / carbon boat. *I'm not a fan, btw, particularly of the 'frybridge.' So I'm just curious from the people who've been inside at cruise speed / race speed, how annoying is the sound in a superlight, all carbon boat? Not at all an issue? Sometimes? I imagine this can and is most easily addressed in one's options for lining the inside of the hulls / bridgedeck. McConaghy MC60 Performance Catamaran
  5. dcnblues

    Gunboat 68

    Yeah, I'm curious about polars. -Are they all done in the computer before the boat even gets wet? Or are they modified during sea trials? What's that process like?
  6. dcnblues

    Gunboat 68

    His name wasn't Carol Shelby was it??
  7. dcnblues

    Gunboat 68

    I always liked the bit from Zen and the art of motorcycle maintenance where he meets the dad who is buying all the individual parts for a Harley for his son. And they both agree that the kid will know a lot more by the time he gets them all together. Of course that was the 60's...
  8. dcnblues

    Gunboat 68

    I had another thought regarding the GB 68, as it is a 5 million dollar boat. What a luxury it would be to have a lighted camera image available in the cockpit of the underwater center board and sail drive, and of the rudder... Both lights and cameras have become pretty small and fairly low power. It's a real pain that that would mean four through hulls, as I can't think of a better way to do it, but my God, what a luxury to be able to just switch that on (at night especially). Or, incorporating a power and video feedline through the existing thru-hulls maybe? Yes, perhaps even extending the existing through hull... And having a small but decent lens or lenses which could monitor both the board and look forward. How valuable would that be in shallow water? (Obviously only clear water). Just a thought. Way less work to put a GoPro on the end of a boat hook, of course... Another thought is about the tiller. For people who order the option, do they get two or do they only get one and move it when tacking? Is it carbon fiber as well? I'm guessing yes. My thought is that one would also greatly benefit from a custom pole that would be longer and stronger than a conventional boat hook and customized to the curve of the hull and the length of the centerboard. Fishing nets and even clusters of kelp can be massive and while under way having something effective enough to pole under the center board And away from the boat might be highly valuable. (I'm thinking a solution that would be able to clear the problem without just pushing it down the hull to the prop and then the rudder).
  9. dcnblues

    Gunboat 68

    So much this. I feel sorry for the 95% of the population that has no knowledge or conception of basic hands on fixing things. I file it under the many failings of the way our culture educates it's young. I actually read a good article that said a very serious contributing factor to winning world war II was all the farm boys who were hands-on mechanics and who kept the equipment running without any training. The article went on to argue that competing armies didn't have the same advantage. Maybe it's true for cruisers too...
  10. dcnblues

    Gunboat 68

    I'm curious: Hypothetically, if you went cruising with a GB 68, would you also bring some carbon fiber, or would the fiberglass just be a temp fix until you could do a proper job in a yard?
  11. dcnblues

    Gunboat 68

    Hmmm, found this. "...loud knocking noise of the old boards." So it does happen. When I think of 'bearings,' I think of something with internal rotating parts but I'm getting the impression that in the context of trunks for daggerboards, it just means a slippery sleeve. Slim's new Daggerboards *Almost forgot: ""shark finned" the last few feet so that when we snag a fishing pot line or something we have a chance of it just gliding off." Not sure how I feel about this as a benefit. Maybe a vortice reduction benefit? But it doesn't seem like it would help it's intended purpose much, and does seem like it would hurt hydro-dynamically as much as it would help (and it would add to draft).
  12. dcnblues

    Gunboat 68

    Still on Dagger boards, I'm curious about the relationship of the sleeve to the board. I imagine that of course it needs to be loose enough to slide easily up and down, and to prevent wear on either surface, but the looser that relationship, the more prone the system would be to banging, especially in rougher blue water. An obvious solution would be some kind of cinches at deck and hull bottom level, but I'm not aware of any such system. So how is a modern system designed, and what is the current thinking on how you balance stability versus ease of use? Thanks.
  13. dcnblues

    Gunboat 68

    Structural benefit? They wouldn't be there for a structural benefit. They're there so that you don't have to mop up sea water out of your cabin or off of your bunk. And they are often raised above deck level in the hopes of making it harder for the water to get in. So it doesn't seem like rocket science to put a drain in that extra space off the deck. And the valid question would be what structural penalty would you pay for the drains? What added price? Me, I'd pay a lot. Car roofs want to be stiff and light too. But car designers don't seem to think they can fight off surface tension / capillary effect, so maybe boat designers should get on the same page. GunBoat did, and I think they deserve a round of applause for doing so...
  14. dcnblues

    Gunboat 68

    Well, real life sure likes drain tubes in sunroofs and deck hatches. Works in cars, seems to work on the GB 68. I wonder why experienced sailors like yourself haven't created a demand for hatches with drains which would defeat the surface tension trying to otherwise make those hatches leaky? Hmm, I wonder whether it might be an attitude that condemns anything not done the old way as 'stupid,' and is arrogant enough to use personal attacks even when they can't get their facts straight. I'll tell you what, Sparky: You stick with tradition. I'll stick with innovation (and thank god you weren't anywhere near the design board for the GB 68).
  15. dcnblues

    Gunboat 68

    a) most people (including myself) forget that without oxygen, stainless isn't really stainless and corrodes / cracks (so if you've ever put tape over any part of your standing rigging, you may want to dye test those parts), and b) it's weaker than painted steel and several times weaker than carbon (I thought it was around 1/2 the strength, but it's apparently more like 5x weaker. My bad). Still, when SpaceX decided to switch manufacturing to SS because it's 60x cheaper than carbon and would do the job for a big spacecraft (even so far as to have a porous outer layer on one side to sweat out methane as an evaporative cooling technique), I thought it was interesting enough to share a link on this topic with the hot carbon boat and ask for clarification about the above facts. I probably shouldn't have. Sorry.