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Frank

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Everything posted by Frank

  1. Essentially then if there is any risk of the raw water system being submerged have an anti siphon loop (ASL) between the pump and the heat exchanger as well as an exhaust riser. The ASL prevents a siphon effect creating undesirable raw water flow when sufficiently heeled. The Exhaust riser prevents the engine being flooded should water fill the exhaust from either issue ie (a) A siphon effect as mentioned above or, (b) Elevated pressure from very high sailing speeds forcing water circulation, which is presumably only a worry for fast multihulls.
  2. I heard recently of an issue with SD units on Leopard Catamarans, I thought some might find it interesting. The story goes that in certain conditions water pressure impinging on the Sail Drive raw water intake can cause flow through the system and into the exhaust without the engine running. There is a blog on this in the cruising forums somewhere and one person even disassembled the plumbing and witnessed it while sailing. Apparently If the raw water plumbing does not have an anti siphon loop the exhaust can fill with water and flood the engine, if the boat is sufficiently heeled, has anyone
  3. The symptoms that caused it to be removed were interesting, basically the seal on the input shaft leaks causing fuel to contaminate the engine oil. Eventually the diesel rich mix gets to the point where it will support combustion then the engine revs madly independent of the throttle and the fuel cutoff wont stop it. To add to the alarm it is attended by billowing clouds of white exhaust, I'd never heard of such a thing nor experienced it until now. In any case its a known issue with the CAV pumps on the Perkins but hopefully we have not done any damage, I stopped it by throwing it into gear
  4. I sailed an NS14 on Botany Bay many years back, they are a great boat, I heard at the time they were somehow related to the Javelin design.
  5. Worked on removing the leaking injector pump from our Perkins 4108. In true british engineering fashion and after 6 hrs of cursing the last bolt requires a 7/32 ball ended allen key bit on a 600 mm extension shaft with a universal joint in the middle. Gotta love old english diesel engines....not.
  6. If it were me I would look for high thrust as per Waikores comment, you may also get better fuel economy.
  7. Go for it ! if you have basic mech skills its no problem, take photos of everything but you should be able to find a manual on line. Mine is not the same model but its 27 years old and just had its second strip and rebuild so its ready for another decade. This time around I replaced the pressed steel cable mounting plate with sheet lexan from and old window.
  8. Another one bites the dust ! https://www.sail-world.com/news/233574/Starboard-foil-and-casing-damage-for-ARKEA-PAPREC
  9. It must be a real head scratcher to model the load cases for these boats, there would be so many variables to account for. I would imagine the instantaneous loads from slamming into waves could at times be horrendous, like hitting the boat with an outsized sledge hammer. Its amazing they last the distance at all, its a real tribute to the designers engineering skills. Many years ago a colleague related a story whereby Boeing sales reps were touring the world visiting prospective customers for the 787 dreamliner. Since there was a lot of suspicion about an all carbon fibre airframe they
  10. Yep, agree with that, anecdotally I heard of a 34 footer where the instructions were " Replace the engine and send me the bill" 50K later !
  11. I agree 2flit, years ago I had experience designing repairs for airframes and based on that I'm confident the mast would not be significantly weakened. I measured up last night and the attaching screws are 4mm at 70mm spacing there is probably 80 to 100 to holes to drill and tap, so I'm more put off by the amount of work involved than any structural concerns. Also it wont do much for the cosmetics unless you're a colander The sailmaker was concerned that a free standing luff would move around too much and generate chafe on the stowed mainsail particularly if you a carried the rig f
  12. Frank

    Etnz boat 2

    These modern AC boats must present a fascinating head game for the team modelling the fluid dynamics. I'm guessing the hull is in some sort of ground effect and there must be an endless list of hydro and aerodynamic factors to optimize at 50 knot +.
  13. The budget for a re-engine on my Carpenter 29 was approx 16K by doing the work myself, 20 to 22 K if I replaced the Sail drive leg as well.
  14. Some good possibilities there thanks Carpe Diem, I will discuss these with the sailmaker. BP sorry I haven't explained the situation well but basically the track needs to be moved further away from the mainsail luff groove. The track extends from below the gooseneck almost to the second spreaders and is fixed with screws at 150 mm intervals hence re-positioning it involves a lot of new holes, the mast height is 51 ft. We want to retrofit batten cars with external rollers but a test fit shows the rollers will foul tri sail track. Chrs
  15. Probably about as well as the 40 yr old Saab 8hp "Auxillary"
  16. I have a situation where I need to move the tri sail luff track on the mast, doing so will involve adding yet more fastener holes which I would prefer to avoid. I have heard of a tri sail arrangement where the luff is free standing using spectra as a luff rope. The sail is then hoisted on the main halyard and secured somehow at the foot. Does anyone have experience with this or has seen one set up ?any advice appreciated, I will check with the local sail maker as well. chrs
  17. Quite a few of the glass D28's had osmosis, dare I say it they are known for it (with due apologies to D28 owners past and present). Osmosis is not the big bogeyman it once was but it would be worth enquiring if it has had any remedial treatment in that area. I know of a local all GRP one that sold this week for somewhere around 20k I think. All uup if the wooden top is mint,the engine has been upgraded, the sails, running and standing rigging are in good to very good condition and the accessories are good then 20K would seem good value to me.
  18. Frank

    Boat on Boat

    With the new AC designs looking to turn on a dime does anyone think there will be more boat on boat action than with the catamarans ? This action adds to the drama and if you can force errors such as a fluffed turn it could be a powerful attacking or defending strategy. Most commentary is that the foil arms would make this dangerous for both vessels and that it would be best to stay out of trouble. My sense is that we will see relatively more close manoeuvering than in Bermuda.
  19. Thanks Matt, my thoughts too, I will check with the rigger at HMB as well.
  20. Does anyone have a preference for using a shouldered rigging pin vs one secured with split pins at both ends ? My thinking is the former is better since one less split pin equals one less failure point.... thoughts ? Secondly should the split pin always have a washer behind it ? on our boat the forestay top pin is not shouldered and there is no washer behind the split pins it just doesn't look "Proper" but maybe I'm just being a Nana, the tangs are aluminium.' Let me know what you think but the Forestay pin is slated for replacement with a shouldered one. Chrs
  21. Thanks for the input folks, it is a Ronstan Car and track, and it seems a captive bearing car will work on the existing extrusion so he is steering towards one of those, cost of 0.5 BU
  22. Wouldn't you classify the new gen IMOCA boats as flying machines ? there is not much of the hull in contact with the water when they are at pace
  23. I like the icons for the new gen boats the winglets, makes them look like ice sliding penguins, well after a few gins maybe Its going to be an epic race and its fascinating to see how sailing technology continues to evolve just when you think they might have run out of ideas.
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