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Tom Lathrop

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Tom Lathrop last won the day on November 15 2019

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About Tom Lathrop

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  • Birthday 09/17/1931

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    Oriental, NC
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    10/08/2019

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  1. Don, I sent you a note on your site.
  2. Don,  After my reply on your post about the transom, the thread died.  Since my suggestions are completely counter to the plan your took in repairing it, I expected some kickback.  Instead there has only been silence.  As an engineer, although not in structures, I am pretty certain that my thoughts on the forces involved are correct and that a knee as seen on many plans is the wrong way to handle this issue.

     

    Even if the transom were strong enough to transfer the force through the knee to the keel, the result would be a hollow or hook in the bottom just where it would do the most harm.  Such knees are a bad idea on a boat powered with an outboard.

     

    Just wondering how this was seen by you and others as I certainly did not mean to shut down an active thread...............Tom

  3. The basic problem here is that the transom is week in bending and the knee to the keel is not a good solution. I consider a knee on such boats to be the wrong way to go about it. It does not work against the forces properly that a transom gets from an outboard. Heresy, I think not. Analise the forces on the transom when an outboard is thrusting the boat. An outboard generates a force forward at the lower or propeller end and the same force is aft on the upper end of the transom and forward at the keel. A weak plywood transom like yours is opposite to what is needed to counteract these forces and the knee is useless. None of the outboard boats I have built in 60 or so years have had a knee and none have ever experienced a problem like yours or too many boats built from plans that specify such transom support. The keel of your boat is quite able to resist the forward force of an outboard without help and the weak (in bending) plywood upper transom is just what you don't need. The best method is to have a non-bending (lateral) upper transom that transfers the force to side decks, sides or adequate sheer structure. A strong board on the forward face of the upper transom that is adequately secured to decks and sides strong enough to take the force is the best method to cure your problem. I think the transom to keel knee is a left over from older boat construction and is not the most useful way for new boat and especially those with outboard power even though many designers specify them. There are several means of resisting transom deformation by transferring the transom twisting outboard forces to the boat structure. Strong and well secured knees between a stronger upper transom and the sheer structure can take care of thrust from small outboards in a way that resists this force. on a boat without side decks. Larger outboards with large such forces need more structure between the upper transom and the boat side structure.
  4. Most men in their 80's have trouble getting back in a capsized or swamped boat or one in dry conditions after expending the energy used in offshore conditions. Running or managing many races of relatively high level competitors who face far less energy requirements have shown this to be true. I've seen healthy and apparently active sailors need considerable help after a capsize in boats designed to allow this easily for younger sailors. Its easy to ruminate about what provisions need to be made to a boat and what equipment would allow the older sailor to get back a board and continue sailing. Such discussions should probably take place in very sober conditions and then tested out to see if it is practical or possible. I sailed well past my 80th year but, in practical moments, I knew that there were seriously degraded human issues to be dealt with. It has been rare that a serious accident or death has claimed a sailor over the 60 years of my involvement with sailboats but it has not been a non existent event. In each case, the cause of the loss has been determined only because it happened where other people were able to witness the event, ether directly or by evidence. In this case, that appears not to be possible and possible steps need to be studied and taken where possible, practical or useful. We all feel the loss of Jim Slauson acutely as we would feel the loss of any member of our sailing sport even though most of us may not have known him personally. As I read back over this note, it may seem a bit detached but I am unable to make it more meaningful than it is.
  5. Are their any updates on sailorman

  6. Oh my. According to reports from Coast Guard, Sailorman is confirmed missing after they found the boat at sea but empty. At 88, 73 years old doesn't seem so old but memory tells me different, especially in those conditions. I join with all Watertribers in hoping for the best outcome. It's difficult to express true feelings for a fellow sailor in these circumstances but the real limits to our control come forward.
  7. I don't consider your advice as picking on the builder. Posts like this are far too frequent and good repair advice may not be what the builder needs. After all, the situation was apparent all along the way by the guy who did it. How do you expect the guy who allowed this to happen to follow good advice in rectifying it??. The proper way to deal with any resin situation is to make it right at each step and not leave globs to be cleaned up at the end. Like any of us, I am also guilty of not doing clean up along the way as well as I should and curse myself for having to work harder at the end. Never anything an order of magnitude this bad though. If the surface below the resin is anything as bad as is shown, it calls for a big effort to make it right. Otherwise, just ignore it and use the boat as is. If it's waterproof, it will still be a boat and the fish don't care.
  8. For a different purpose, I use "Squiding line", which is the same or similar to braided fishing line. Available in Dacron or nylon in a range of strengths and very strong.
  9. My friends were flown back to Melbourne on a Hercules aircraft but had to leave their car, gear and the boat behind. They will go back and pick up the boat and car later. Hope all works out well for them as the near term looks pretty safe and good. Future weather does not look too good for Australia according to long term weather reports. The current fire situation and weather were not a surprise and were predicted. It seems the Australian PM dismisses expert advice almost as well as our own leader.
  10. I'm in touch with a builder in Australia who is on vacation in eastern Victoria where evacuation is common. Many have been evacuated with some being taken by landing craft and other boats. They are OK as of now although nearby fire and smoke must be pretty bad. Travel by many roads is impossible to mobility is limited. Temperature is very high and, with a spark, stuff just explodes. We hope for the best as this is about as bad a weather event as can be imagined. My floods seem less severe after seeing this. Some pictures and video of an Island off the coast of Victoria. https://www.news.com.au/technology/e...86471fa20c88dd
  11. What I asked is clear. No opinions were offered from me. I did not ask anyone to evaluate the Australian builder I am using although they have many successful aluminum boats as well as provide extensive hands on training for prospective builders. I understand and stated that boats or kits shipping from Australia may too much for many in the USA. The questions were only related to what issues wooden boat builders might have with aluminum as a material.
  12. I posted this thread with the thought that wooden boat builders would have some thoughts about aluminum as a viable and practical material for a Bluejacket. So far, none have expressed any thoughts along those lines, such as: What are opinions of aluminum versus plywood as a boat material? That is, not regarding the obvious ones of building expertise or price. What are the issues in contemplating an aluminum boat for the average home builder? Which is more desirable aesthetically? Which would you rather own? Which is less maintenance? Anything else?
  13. I know some facts Egbert, but am waiting to get more definitive data after the boat has completed construction and trials. Each model will be somewhat heavier but I don't think it will be as great a change as I originally feared. This is due to my assessment of the knowledge and skill of Plate Alloy in use of aluminum in building boats. Some features of the Bluejacket design are effective in mitigating increase weight. Probably foremost of these is the large water plane and buoyancy that offer a much lower bottom loading in weight per square area compared to other boats. At least in these boats, less weight means more performance while using less power and fuel than commercially available options. For those who have a desire to build or have a wooden boat, I don't think the aluminum version will be a great deterrent to building the current wooden model. For those with less time, space or opportunity to build their own, as well as finances to buy a more expensive aluminum one, availability of a commercial Bluejacket will be a positive. For my part, I still favor the current wooded model because I just like the ability to build my own.
  14. In case some people have wondered what is going on with Bluejackets, this is the latest. Plan sales and building is moving along, although at 88, I have started slowing down on all facets of boating. There have been several inquiries about whether a Bluejacket can be built in Aluminum. My answer has always been that a BJ can certainly be built in aluminum but I am not in a position to do detail design and manufacturing in that medium. Quite a few aluminum boats have and are being built in the Pacific Northwest and are used mostly for fishing. None of these boats are, to my knowledge, optimum for cruising, which is a Bluejackets stock in trade. Weight of aluminum is a lot greater per unit of volume than wood which is the main reason that attempts to use other materials have not been pursued to a good conclusion. Weight of the boat and resultant performance advantages of light weight was the driving force behind many decisions in the Bluejacket design. Earlier this year, a builder of aluminum boats in Melbourne, South Australia contacted me about the possibility of using aluminum for 100% of the boat structure. After considerable discussion of what would be involved and by his enthusiasm for the project, work was started on evaluating whether a Bluejacket could gain the benefits of non-perishable material and rugged aluminum structure while retaining its better qualities of performance of the wooden model. Of course, the benefit of an ability to buy a commercially built Bluejacket from a quantity builder was also a main factor. How well this is accomplished is a bit unclear but the prospects look good. While I did do some work on this project, the main effort has been from John Pontiflex who owns and operates Plate Alloy Australia Pty Ltd in Melbourne, Victoria, Australia. He builds a fairly large range of aluminum boats that are used mainly for fishing, either commercially or privately. Some modification of structural parts of the wooden Bluejacket was required to utilize aluminum but the design was followed very closely. He says that cruising boats are not a big item in Australia at this point and none that approximate a Bluejacket are available. Therefore a commercially available aluminum Bluejacket may well be a viable offering for Plate Alloy. He also teaches aluminum boatbuilding and the welding techniques necessary to make a good job in one week (or so) courses in various areas of Australia. CNC kits can then be a large part of Plate Alloy’s offerings. Cut files are, of course, available but legal requirements safeguarding their use by those other than Plate Alloy will be required. Shipping costs of ether boats or building material from Australia to the USA are high. Such costs may make shipping of boats or part inventories infeasible but that can be worked around is not known yet. The attached photos show the boat in its unfinished form at the trial launch. The engine is not equipped with final controls and is a larger size with much more weight than the 70hp specified. This engine is a larger than recommended size as that is what John had at the time. Performance is expected to be good with the recommended engines up to the Yamaha 70hp model. Yamaha outboards from 50hp to 70hp all have the same displacement although the 70hp will provide the best high end speed. In case some people have wondered what is going on with Bluejackets, this is the latest. Plan sales and building is moving along, although at 88, I have started slowing down on all facets of boating. There have been several inquiries about whether a Bluejacket can be built in Aluminum. My answer has always been that a BJ can certainly be built in aluminum but I am not in a position to do detail design and manufacturing in that medium. Quite a few aluminum boats have and are being built in the Pacific Northwest and are used mostly for fishing. None of these boats are, to my knowledge, optimum for cruising, which is a Bluejackets stock in trade. Weight of aluminum is a lot greater per unit of volume than wood which is the main reason that attempts to use other materials have not been pursued to a good conclusion. Weight of the boat and resultant performance advantages of light weight was the driving force behind many decisions in the Bluejacket design. Earlier this year, a builder of aluminum boats in Melbourne, South Australia contacted me about the possibility of using aluminum for 100% of the boat structure. After considerable discussion of what would be involved and by his enthusiasm for the project, work was started on evaluating whether a Bluejacket could gain the benefits of non-perishable material and rugged aluminum structure while retaining its better qualities of performance of the wooden model. Of course, the benefit of an ability to buy a commercially built Bluejacket from a quantity builder was also a main factor. How well this is accomplished is a bit unclear but the prospects look good. While I did do some work on this project, the main effort has been from John Pontiflex who owns and operates Plate Alloy Australia Pty Ltd in Melbourne, Victoria, Australia. He builds a fairly large range of aluminum boats that are used mainly for fishing, either commercially or privately. Some modification of structural parts of the wooden Bluejacket was required to utilize aluminum but the design was followed very closely. He says that cruising boats are not a big item in Australia at this point and none that approximate a Bluejacket are available. Therefore a commercially available aluminum Bluejacket may well be a viable offering for Plate Alloy. He also teaches aluminum boatbuilding and the welding techniques necessary to make a good job in one week (or so) courses in various areas of Australia. CNC kits can then be a large part of Plate Alloy’s offerings. Cut files are, of course, available but legal requirements safeguarding their use by those other than Plate Alloy will be required. Shipping costs of ether boats or building material from Australia to the USA are high. Such costs may make shipping of boats or part inventories infeasible but that can be worked around is not known yet. The attached photos show the boat in its unfinished form at the trial launch. The engine is not equipped with final controls and is a larger size with much more weight than the 70hp specified. This engine is a larger than recommended size as that is what John had at the time. Performance is expected to be good with the recommended engines up to the Yamaha 70hp model. Yamaha outboards from 50hp to 70hp all have the same displacement although the 70hp will provide the best high end speed. The video does not work for me as yet.
  15. Its a Walkabout and may be the only one built. I went over to the B&B Messabout from Oriental today for a beautiful and mild day and many fine boats. Maybe the nicest was the new 28 foot sportfisherman that Graham designed. Really fine work. Great to see all the new and old boats and great to see friends, old and new. Carla's birthday celebration too. Heck, we deserve all the good fortune we can get these days. All the fried chicken, BBQ, fixings and drink that you could eat.
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