New to site, design and looking for perspective!?

Discussion in 'Boat Design' started by bjdbowman, Apr 23, 2017.

  1. garydierking
    Joined: Sep 2004
    Posts: 181
    Likes: 54, Points: 28, Legacy Rep: 174
    Location: New Zealand

    garydierking Senior Member

    A 32' catamaran is too small for off shore cruising, Unless it's a Wharram, the wing will be too low and you'll regret it forever.
  2. Tom.151
    Joined: Jul 2009
    Posts: 194
    Likes: 10, Points: 18, Legacy Rep: 38
    Location: New England, USA

    Tom.151 Senior Member

    Imagine standing at the foothills of a mountain range, off in the distance is the 'Everest' of this range. The foothills is where you are if you insist on doing both the design and the build of your dream boat.
    (1) Your posts are concerned, talking, and asking for advice more about the foothills. which are comparatively trivial in the full scope of things (i.e. both the complexity and cost aspects) and the last things that need to bev resolved.
    (2) the 'Everest' in the distance, the really big problem, is the aero/hydro/structural computations needed before you can begin to source materials. For which, as you said, you 'have no clue'.

    Rest assured that in this thread, you have already gotten expert advice from some of the best, experienced, experts in small (under 60 feet) sailing boats (mono and multi).

    So far you have been deaf to their input. Some might say arrogant in your quick dismissal of their valuable and generous contributions to the thread you started here.

    It is in your own best interest, if you are sincere about wanting to go sailing in a boat that's both competent and safe for your family, to find a way to understand that you are not yet listening here. Then change course and start listening instead of explaining why you're 'righter' about the least important aspects of the project than the contributors that have tried to shed light on both your 'instincts' and choices.

    All the best,
  3. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 491, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Good to see you post Ryland.

    BJD, having an engineering background should help considerably with you project. In this, you should already know the amount of research needed., across several disiplines. The very first thing is a well defined SOR, to keep design goals and performance envelop targets. Next up, tough decisions about sectional shapes, volumetrics and of course hydrodynamics, aerodynamics, all keeping the SOR targets in mind. With this you can martch around the sprial, which will make material choice pretty obvious, once constrained by the various concerns involved, (costs, skill sets, tools, personal skills, etc.). Than again, you might just find the build site, skill/tool sets and budget is best served with a set of stock or slightly modified plans as a much more viable option. This is what the great majority find (95%), you'll be no different, though possably more inventive and clever, but building new, especially as a self designed ocean going craft, is the second most costly method to get this sort of thing done.
  4. bjdbowman
    Joined: Apr 2017
    Posts: 68
    Likes: 2, Points: 8, Legacy Rep: 10
    Location: Florida

    bjdbowman Junior Member


    Thanks... I just sat down to read this thread... I have not yet replied to any of the comments above. Thanks for the advice. I agree with you and most of the comments / post / replies within the thread.

    I guess that I am not good at communicating. Too much happening here in this thread to even know how to start to reply to all of it.

    First: I understanding that everyone else knows everything and I know nothing. I am not righer than anyone nor do I intend to communicate that.

    Second: I will ultimately work with a naval architect to develop the "non-yacht" 32 foot long cat that I want to build. I don't see anything out there that I would like to or would want to build. I gave so much info on the original post because I wanted to give everyone the reason why I want what I want. This is all a direction not written in stone.

    The closest boat that I have found to date to meet my requirements is the 32 foot PDQ.

    Third: I think that everyone assumes that I am using the "male mold" foam as a structural component within the structure of the hull/boat. I am sorry that I did not clarify that point. This is not so... leaving the foam inside the boat is for the sound, buoyancy and thermal insulation, which I though was the requirement of the foam with the added bonus of aiding in forming the structure. I am not going to use injection/vacuum bag method, but simple old fashion fiberglass one layer at a time.

    All of the structural components integral with the hull, interior, topside and deck would be a composite held in place by the insulation during layup. This would be a one-off fiberglass built on a foam male mold. Imagine an inverted plug cut from a solid block of foam with a 5 axis CNC. The stringers, ribs, strakes, etc were all cut within the male mold to accept and hold the composites parts. With this method it would be simply a fiberglass boat made on a male mold. In this concept above the hull would be removed from the plug. A female mold is too much work and a waste of time/money for me, therefore I figure that the "male mold" could be utilized within the boat so it would not be a waste of time or money. Naturally I thought about the insulation idea because of the sound and thermal properties. I only wish I could figure out how to incorporate a radiant barrier within the boat.

    Forth: My last boat had issues only where there was "wood" within the structure being within the topside, the hull or the interior. I don't want wood within my boat unless there is no other option. As I see it there are other options... it is 2017 and there are a lot of great boats being built. I know that many will dive into this comment as they are solid wood guys... That is fine, my naval architect friend is a wood nut as well. I however am not a wood nut and even though it may be cheaper or faster to build or easier to work with... you can keep your wood on your projects, just let me have my composites... Deal?

    Fifth: I am thankful for this community. I have read a lot of threads within this site. I understand that there is so much thought into a hull structure. I tried to keep the "general" questions on point but failed. I see many fine and accurate comments / replies / post above. I am learning tons. I liked the link to the foam core construction method, and I read all the info on that site.

    Sixth: I am not being arrogant or dismissive to any posts within this thread. I am asking and trying to understand perspectives. I am sorry, but I am not going to simply buy a boat because of someone's opinion when the whole purpose of this build is the build. Nor am I NOT going to build a 32 foot long cat because someone's opinion is that the 32 foot is "too small" for off-shore cruising. I want a specific set of qualities and I am not going to spend tons of money and time on something I will end up saying "if I only did this or that", or "I wish I had something different".

    Again, there are many 32 foot long cats out there as cruisers. I looked at many but none have grabbed me to the point where it was at the level of service and the level of safety for me. Most were too fancy and too weak. I don't want a thin slice of fiberglass or wood between me and the ocean nor do I want all the trappings of the production models. I want the best that my world has to offer... at the valuable price of my time. I want this build to go fast and easy. I don't want to spend weeks sanding or prepping to paint. I was also thinking of using Kevlar on specific parts of the boat where added strength is needed and carbon fiber on selected components where weight savings in needed.

    Again I am not an expert... I am only speaking of a general direction in all of these post. I will learn and bend with the learning curve.

    I understand what I want is not out there in kit form, but maybe someday. I like the Richard Woods Skoota 32, but again I think that this would need more work to tweak it to the accommodations that I am looking for.

    The SA20 is a twin cabin, but again just staring design direction.

    Again, I don't want a 32 foot production boat... but a solid 24 footer stretched into a 32 foot. I want to utilize the length with two cabins and I want a center cockpit at the mast. The PDQ 32 is closer to my concept that I could find but not yet there.

    I was thinking a general configuration:

    fore deck 4 feet long
    front cabin 8 feet long
    center cockpit 8 feet long
    rear cabin 8 feet long
    aft deck 4 feet long

    32 feet total bow to transom with a 30 foot waterline.

    Don't hold me to that, this is just a general starting point... and the cabins are for camping level of service not a luxury 6' of headroom. I would hold the center cockpit and adjust the outward direction as the design progress. This is the broad brush concept that I am looking for. If all the dimensions have to change to 6 feet than they would change. I'm only at a starting point for direction.

    Within the cat hulls is where the 6 foot headroom would hide.

    Again, If I must I will go back and comment on everyone's posts, but I am not here to argue or dismiss any comments. I appreciate everyone's comments and efforts.

    I don't have any time today to comment but I will continue to research and read other posts / sites.

    Thanks again,

  5. bjdbowman
    Joined: Apr 2017
    Posts: 68
    Likes: 2, Points: 8, Legacy Rep: 10
    Location: Florida

    bjdbowman Junior Member


    Nice comment. I agree with you. If I could find the right boat plans, I will go that direction of just minor mods which would save a ton of time, energy, and money.

    The trick is finding something close... I'm going to look at the Simpson designs to see if something there might fit.


  6. Squidly-Diddly
    Joined: Sep 2007
    Posts: 1,827
    Likes: 143, Points: 63, Legacy Rep: 304
    Location: SF bay

    Squidly-Diddly Senior Member

    You should build a 1/3-1/4 scale version first, to:

    1)test out your novel building method

    2)test out your novel mid cockpit arrangement.

    That would be enjoyable, and you could haul it around unfinished to have stuff done or get advice.
  7. bjdbowman
    Joined: Apr 2017
    Posts: 68
    Likes: 2, Points: 8, Legacy Rep: 10
    Location: Florida

    bjdbowman Junior Member

    Yes... I agree with the comments... why try to reinvent the wheel? I am leaning to a one-off composite build-up within a female mold. If I build a plywood multi-chine mold I could do my lay-up and then add composite frames and stringers internal on the lay-up and then add polystyrene insulation on the interior and then encapsulate the insulation with a second round of lighter composite for the interiors. I need the acoustical and thermal insulation, this is one of the main reason I am wanting to build a one-off.

    I don't like wood on a boat, I am planing on using the boat in the extreme cold and the extreme heat, and this is going to be a live aboard with heat and air-conditioning.

    Other than that, I have added a few new ideas, 1) segmented construction to make the parts manageable and add to the construct-ability by one person, 2) designing in multiple redundancy on all systems, 3) a new bi-directional hull design (like a Proa) with the ability to construct the aft hull segments identical to the bow hull segments using the same mold configuration, and finally adding in lifting foils to reduce drag/wetted surface and increase speed.

    Still much to do... I am looking for advice and professional assistance with the design. I have a few years to work on the design as I gather the tools, materials and components. I like to design around the systems/materials that I will have on hand, ie: heads, hatches, engines, etc.

    Let me know what you think... I enjoyed the last round of comments as I am learning, reading, and enjoying this site and others.

    This winter I started harvesting some Southern Yellow Pine to use for the tooling/production process/sheds. I have seven acres of large/old shortleaf pines, so I was able to select some mid size, straight and clear logs for construction lumber. I found a guy that will let me use his Mizner Saw Mill, but I have to hall the logs 40 miles to his house. I also bought a flat bed trailer this winter to move the logs, so now I just need to be able to load the trailer with the logs and a tractor at the same time so that I can get them to the mill. No I don't have a tractor yet, but it's next on the list.


  8. bjdbowman
    Joined: Apr 2017
    Posts: 68
    Likes: 2, Points: 8, Legacy Rep: 10
    Location: Florida

    bjdbowman Junior Member

    great advice... thanks! I am talking my time and experimenting with smaller projects first.
  9. bjdbowman
    Joined: Apr 2017
    Posts: 68
    Likes: 2, Points: 8, Legacy Rep: 10
    Location: Florida

    bjdbowman Junior Member

    Thanks... I read your post and the link. all good points. It's as if everyone thinks that you need to create a master piece in order to build a boat. I have seen many boats that are just work boats that were built by sight and not a single drawing or calculation. Not everything has to be perfect in order to fulfill it's purpose. I never plan on selling my boats, because this is not the intention. I will not leave my family with the hassle of having to deal with them after I have gone from this earth. I would rather give them away or cut them up for the landfill. I know that you will not understand this... and that is okay.

    There is nothing wrong with making mistakes... how else do we learn? I am learning and I intend to do this until I take my last breath.

    Forgive me if you think that I'm just an idiot... that's fine, I'm okay with that. I take every comment and digest them. I read and keep on reading.... but I am not just going to give into ideas of simply giving up. What most people regret is what they didn't do... Some people like the challenge even if it kills them... just think of Skiing and climbing mountains... so many people die every year from doing something that they love.

    I'm still in the game, and I will get there, where I want to go, it's just a matter of time, and patience.

  10. bjdbowman
    Joined: Apr 2017
    Posts: 68
    Likes: 2, Points: 8, Legacy Rep: 10
    Location: Florida

    bjdbowman Junior Member

    I just want to say that I love a good challenge and problem solving... I've been doing engineering for almost 40 years now, and I'm still loving it. I have designed some pretty cool projects in my days. I worked in coastal engineering for 12 years, back in the 90's and early 2000's) and during that time, I learned a lot about ships, boats and the incredible forces of the most powerful element on our planet (egos... oops, I mean water).

    I helped design the worlds largest mooring buoy, at the time, for the worlds largest cruise ship, at the time... (Royal Caribbean - at Labadee Haiti). So a small 34 foot sail boat is nothing that causes me any concerns... I love the process and learning. I don't think that you have to be a rocket scientist to build a rocket (elon musk comes to mind - joke) nor do you have to be a certified naval architect to build a boat. Just my thoughts... I do appropriate all of the comments, but assuming that someone is an idiot without truly knowing them, is similar to judging a book without even seeing the cover.

    Thanks again to everyone... I'll be back on this later on, as I have many other projects on the front burners right now.
  11. tspeer
    Joined: Feb 2002
    Posts: 2,319
    Likes: 295, Points: 83, Legacy Rep: 1673
    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    I've not used Foamular 150 to build a boat, but I have used it to build model airplanes. It sands easily, so I don't understand why you wouldn't want to fair it properly. Fairing is not just a matter of appearance - it's important to the performance of your boat. The glass and epoxy is going to be expensive, and construction of the hull structure itself is a small part of the overall labor to complete the boat. So some additional time spent fairing will add tremendously to the value of the boat. On a value-added-per-hour basis, it may be one of the best ways you can spend your time.

    I question whether Foamular 150 is dense enough or tough enough for the job. There are foams that are expressly made for boatbuilding, like Corecell. Their properties, such as shear strength and toughness, are tailored to the right values for boats. They are also easy to shape, so your experience with Foamular 150 would transfer directly to Corecell. Corecell will be more expensive than Foamular 150, but by choosing epoxy over polyester resin you've already indicated you're not going after the cheapest possible materials.

    If just cruising was your primary goal, you'd be on your way a lot cheaper and quicker by buying a used boat, so the designing and building is what's important to you, and you're out to make a statement with it. Every time you look at the boat, you're going to wonder if shortcuts you took early on were really worth it. You'll be retired - I say take the time to do it right and have a boat you'll be proud of every time someone walks down the dock and takes notice of it.

  12. Squidly-Diddly
    Joined: Sep 2007
    Posts: 1,827
    Likes: 143, Points: 63, Legacy Rep: 304
    Location: SF bay

    Squidly-Diddly Senior Member

    I "get" that certain people dislike certain processes. I can't smooth drywall mud or finish concrete to save my life, and I've had best in biz attempt to train me, several times. :(

    What you need to do is find one or two helpers with this skill. Similar to working with Mud, there will be guys with the skill and like doing it, who would be lost in overall design.
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.