Things I have learned from building and designing boats

Discussion in 'Boat Design' started by David L. Dodd II, Mar 29, 2021.

  1. David L. Dodd II
    Joined: Jun 2020
    Posts: 36
    Likes: 32, Points: 18
    Location: New York

    David L. Dodd II Junior Member

    Okay this is an acquired knowledge thread. Add on, make it useful.

    Boat Building Rules:

    Boat Building Rule #1: There are a hundred ways to do it wrong and only one way to do it right.

    Boat Building Rule #2: No one notices when you do it right. Everyone notices when you do it wrong.

    Boat Building Rule #3: Time is the only thing you lose the more you try to save.

    Corollary to Rule #3: Every shortcut doubles construction time.

    Boat Building Rule #4: Power Tools make it really easy... to ruin hours of hard work.

    Boat Building rule # 5: If it wasn't fair and symmetric when it went in, then it won't come out fair and symmetric. It will need to come out though.

    Boat Building Rule #6: Never Trust the miter gauge on a miter saw.

    Boat Building Rule #7: If you need a joint to fit tight, tack the two peices of wood together and cut both pieces at the same time. It has to fit tight.

    Boat Building Rule #8: Sand paper is your most important tool.

    Boat Building Rule #9: Go to flea markets, garage sales and antiques shows. Buy every plane and spoke shave you see. These old tools are cheaper and better than anything you can buy nowadays. Regrind the blades or have them reground by someone who knows how.

    Boat Building Rule #10: Measuring twice isn't enough.

    Boat Building Rule #11 If it went in easy, it is probably wrong.

    Boat Building Rule #12: Order is important. Follow the plans.

    Boat Building Rule #13: If you hear that little voice inside your head saying, "I am really good at this." Stop. Put down the tool you are using. You are probably making a huge mistake.

    Corollary to Rule #14: Experts die too. They die with alarming regularity. Never think you are too good to play it safe. (This rule goes for building the boat as well as using it.)

    Boat Building Rule #14: It will always take longer, be harder and cost more.

    Boat Building Rule #15: At some point in every project, you will realize you bit of way more that you can chew. You will be demoralized, You will be angry and dissapointed with your self. The project will seem hopeless and you will want to give up. When this happens, find a small task. Something that will take five minutes. Do it. Four or five hours later when you finally stop working, you will feel better. You will also be four or five hours closer to being done.

    Boat Building Rule #16: Building a model first will save way more time than it takes.

    Boat Building Rule#17: It takes longer to screw than to nail

    Boat Building Rule #18: You need a mullling chair (With apologies to Howard Chappelle).

    Boat Building Rule #19: Chain plates should alway bend at the edge of the support. Never let the chainplate bend above the support, it will be much weaker.

    Boat Building Rule #20: Chain Plates should always bend so that the tension is pulling in a straight line from the support to the terminal.

    Boat Building Rule #21: Never let a chain plate take tension in two directions.

    Boat Building Rule#22: Seal everything like your life depends on it. It does.

    Boat Building Rule #23: Never undersestimate water.

    Boat Building Rule #24: If it moves it will leak.

    Corollary to rule#24: Make sure fittings don't move.

    Boat Building Rule #25: Washers bend and damage the hull. Either double up the washers or use a custom made plate to hold any through the hull fittings.

    Boat Building Rule #26: If a nut and bolt has to hold, take a punch and peen the threads over against the nut.

    Boat Design Rules

    Boat Design Rule #1: Never forget a drawing is two dimesional. Boats are three dimensional. This is why modeled boats often look so much better than computer drawn boats.

    Corollary to Rule #1: Sheers need to faired by builders or they look lumpy when viewed from the quarters.

    Boat Design Rule #2: In theory, theory and practice are the same, in practice they seldom are.

    Corollary to rule #2: All calculations relating to balance of the rig and hull are suspect until proven in a protoype or model.

    Boat Design Rule #3: You can trade displacement for speed.

    Boat Design Rule #4: Head room is good, windage is bad. Best of luck with that.

    Boat Design Rule #5: Simple is better, stronger is better, lighter is better. Best of luck with that.

    Boat Design Rule #6: You pay for efficiency with complexity and tension.

    Corrolary to Rule # 6: Complex things break easier. Tension breaks complex things.

    Boat Design Rule #7: Never have the bow of the boat come to a point under the waterline.

    Corollary to rule#7: A little (very little) tumble home in the bow can add character, but reverse bows are just bad. They look terrible, drench the boat, sabotage reserve bouyancy, get damaged easily, reduce deck space, and snag everything. There is nothing a reverse bow does that an axe bow doesn't do better. If you design a reverse bow, at least design it as an add on to an axe bow, so that when the reverse bow gets smashed off the boat doesn't flood and sink.

    Clarification to rule #7: We are not talking about really big ships with bulbs under the bow.

    Boat Design Rule #8 : Never add a through the hull fitting below the waterline, unless you absolutely need to.

    Boat Design Rule #9: Assume that all through the hull fittings will leak. Make sure the boat will stay afloat if they do.

    Boat Design Rule #10: Build reserve bouyancy into your design.

    Boat Design Rule #11: Wing keels and rudder endplates work great until the tide goes out.

    Boat Design Rule #12: Design all dagger board slots four inches longer than needed. Make sure the plans show in detail how to make a figerglass sealed closed cell foam impact cushion for the back of the dagger board case. Trust me, the dagger board will hit something when the boat is going fast. The foam insert is way easier to replace than the dagger board case and bottom of the boat. The boat is a lot less likely to sink if the cushion is crushed, then if the dagger board rips the case out of the bottom.

    Boat Design Rule #13: Stainless steel is stain less not corrosion proof. Don't confuse the two.

    Boat Design Rule #14: Stainless steel needs to be exposed to air.

    Boat Design Rule # 15: Camber cuts down on water pooling, improves aerodynamics, makes structures stronger, and adds head room in the least objectionable way.

    Boat Design Rule #16: If it is ugly then it is wrong.

    Boat Design Rule #17: Design everything above the waterline to make the smallest waves. Design under the waterline to reduce skin friction.

    Clarification of Rule 17: Use with a grain of salt in non displacement hulls. Lift is often more important that skin friction in these hulls, since most of the hull will be out of the water and the boat will be going fast enough for air resistance to be important.

    Boat Design Rule #18: Down flooding is a grade a number 1 way to sink a boat. Plan accordingly.

    Boat Design Rule #19: Ballast is a drag.

    Boat Design Rule #20: It us much harder to design a boat with a cat.

    Boat Design Rule #21: The ocean can kill any boat without even a thought. Think about how your crew will survive the worst. Designing the end of a boat is as important as designing its beginning.
    Last edited: Mar 29, 2021
  2. bajansailor
    Joined: Oct 2007
    Posts: 3,466
    Likes: 1,434, Points: 113, Legacy Rep: 37
    Location: Barbados

    bajansailor Marine Surveyor

    Excellent! You have summed it all up very well there.

    And I am sure that most folk on here can relate absolutely to most (if not all) of the rules mentioned above.
  3. messabout
    Joined: Jan 2006
    Posts: 3,347
    Likes: 482, Points: 83, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    Looks like Murphy's law's for boat people. I approve of those bits of old time wisdom.
    bajansailor likes this.
  4. Ike
    Joined: Apr 2006
    Posts: 2,654
    Likes: 456, Points: 83, Legacy Rep: 1669
    Location: Washington

    Ike Senior Member

    I think you pretty much nailed it, especially rule 20.
    ondarvr likes this.
  5. David L. Dodd II
    Joined: Jun 2020
    Posts: 36
    Likes: 32, Points: 18
    Location: New York

    David L. Dodd II Junior Member

    First, thank you very much. Second, Please everyone, feel free to add your own rules. Lets fill this discussion up with the gems that only experience give.
    Will Gilmore likes this.
  6. comfisherman
    Joined: Apr 2009
    Posts: 542
    Likes: 266, Points: 63, Legacy Rep: 10
    Location: Alaska

    comfisherman Senior Member

    6 inch random orbital is a wonderful thing after hours with a 5 inch.

    Milwaukee makes the lightest 7.5 amp angle grinder....after hours and hours and hours and hours holding one..... it adds up.

    Own lots of cordless drills. Three fit easily on a belt, one to pilot one to drill and one to run the countersink. Payed for themselves in very few hrs.

    High horsepower shop vacs make fiberglass boat building much easier. Run them often with quality bags..... best dust mitigation per dollar.

    As to the design side of things....

    Everything heavy is easy to make and quick to produce, weight loss is the opposite.
    Will Gilmore likes this.
  7. Benjamin
    Joined: Dec 2020
    Posts: 13
    Likes: 3, Points: 3
    Location: Florida Keys

    Benjamin Junior Member

    If someone else is building your design something will be messed up. If you are building your design, something will be messed up.
    Will Gilmore and ondarvr like this.
  8. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,390
    Likes: 1,039, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    "Handsome is, as handsome does", is probably as much, or more applicable to things boating, as anything else, and especially if it is going to be expensive to "keep up appearances".
    Will Gilmore likes this.
  9. Will Gilmore
    Joined: Aug 2017
    Posts: 892
    Likes: 393, Points: 63
    Location: Littleton, nh

    Will Gilmore Senior Member

    The Will's Axiom for the Asymptotic Completion of Complex Construction Projects (WAACCCP): One can never reach completion of any construction project that involves multiple people with various responsibilities of the different aspects of a job. A job can only approach completion with an every narrowing margin. As each person or group completes their area of responsibility, they will cause some small damage to another aspect of the job, for which someone else will have to come back to repair. Such repairs are likely to require another person to repair whatever damage they may have done to the finish, trim, fasteners, floor, walls, doorways, hatchways, etc. in the setup, completion or cleanup of their work, repeating the process until whatever damages or parts to build become insignificant enough that the foreman or owner declared the job "Good enough for who it's for."

    I did not develop this Axiom building or designing boats, but doing the punch work on the cabinets for a new retirement community where I repaired damaged finish from cleaners, burned countertops from plumbers, broken doors from electricians, etc. Each of them coming in, at the final stages of construction, to repair damage that someone else had caused while doing their work. In my decades long career as a finish carpenter and cabinet maker, I saw it over and over; the more complex the job, the slower that approach to a finished state of zero work needing to be done was, and I never saw it actually achieved.
  10. Dejay
    Joined: Mar 2018
    Posts: 721
    Likes: 138, Points: 43
    Location: Europe

    Dejay Senior Newbie

    Perfect is the enemy of good? :)
    cthippo likes this.
  11. David L. Dodd II
    Joined: Jun 2020
    Posts: 36
    Likes: 32, Points: 18
    Location: New York

    David L. Dodd II Junior Member

    Wow, just wow.
    Will Gilmore likes this.
  12. baeckmo
    Joined: Jun 2009
    Posts: 1,621
    Likes: 624, Points: 113, Legacy Rep: 1165
    Location: Sweden

    baeckmo Hydrodynamics

    The customer is always right......the first fourteen days. From there on, I'm right all the time.
    (cited: my old boatbuilding mentor Sven Jacobsen after rebuilding an interior for the n:th time)
    TANSL likes this.
  13. Will Gilmore
    Joined: Aug 2017
    Posts: 892
    Likes: 393, Points: 63
    Location: Littleton, nh

    Will Gilmore Senior Member

    My father had a friend who ordered a custom sailboat from a well respected yard. He came over and told my father all about the new boat he was having built. It was an expensive and impressive build, so much so that he then told my father that he bought a small house near the yard so he could visit often and make sure they stayed on track and didn't stray from the agreed upon plan or get distracted from their timeline.

    My father said, "Oh Jack, (we'll call him Jack) that's a bad idea. You don't want to do that."

    Jack replied that he needed to be confident that their work was first rate and was tired of getting an incomplete or inferior job from boat yards.

    The Old Man suggested, "Let them do their job, build your boat and get it done without interference from a guy who's always going to be seen as meddlesome and in the way. Then, once you've taken delivery of your boat, sail her down the coast to their competitor and give them the list of all the things they got wrong and let those guys fix it."

    Jack disagreed and followed through with his plan. It took a long time and Jack's visits with the Old Man were filled with woe about how badly things were going. It ran over budget and over time, but finally the boat got built. Jack went in to negotiate the final payment with his checkbook and his list of complaints.

    Instead of handing the yard owner his final check, however, the owner handed him a check for the return of his initial down payment.

    Jack said, "What is this?"

    "It's your money back, I'm not selling this boat to you."

    Instead of going down his list of all the things the yard screwed up that may have given him leverage for renegotiating a lower final payment, Jack asked, "But, we had a deal, why won't you sell me the boat?"

    The yard owner went down his own list of how Jack slowed down production, got in the way of the operation of his yard, insisted on changes mid-construction and created a huge waste of materials and labor. The yard owner said, "I don't like you and I just don't want to sell this boat to you."

    I don't know what yard it was and I don't know what happened to the boat or anything about it. It is a story the Old Man likes to tell to illustrate how fretting and getting involved in aspects of a project outside your area of experience and expertise can be counter productive, even disastrous.
    bajansailor likes this.
  14. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,390
    Likes: 1,039, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    I can just see Jack getting into an immediate fit of indignation, and threatening that lawyers will soon be on the case. I think we have all been in a mechanic's workshop or the like, with an hourly rate announced on signage, but doubled if the customer watches.
    Will Gilmore and clmanges like this.

  15. Ike
    Joined: Apr 2006
    Posts: 2,654
    Likes: 456, Points: 83, Legacy Rep: 1669
    Location: Washington

    Ike Senior Member

    Back in the 90's (Was after 95) , I went to the first West Coast IBEX in Seattle. I was a presenter but in my spare time I sat in on a lot of other seminars. A local builder was asked by someone in the audience what is your biggest problem when building custom boats. He told a very similar story. But he ended up selling the boat anyway, but at a much higher price than initially agreed on because of all the changes the owner kept asking for during construction.

    Some one in the Coast Guard contracting office told me years ago when I was handling some contracts for the Coast Guard, take the best estimate, then double it, and you'll probably be closer to the actual price. I found out over many years that was a pretty good rule.

    For many years I had a sign on my desk with a quote from Robert Heinlein, the author. "Never underestimate the power of human stupidity. " In my case I think that applies to boatbuilding as well.
    bajansailor and Will Gilmore like this.
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.