Boat Design Help

Hello, I feel that it'd be too long to post everything here, so I'll give a link to my original post: http://www.byyb.org/forum/index.php?topic=3489.0

Summary: I am taking measurements from an unnamed boat (it is ocean proven) and stretching the LOA from 20 ft. to 24 ft. and beam from 7 ft. to 7. 8 ft. There was some concern from a member from this forum, who urged me to start a discussion here. I have all the specific numbers on hand to post if requested. Please advise. Thanks.

 

Welcome to the forum.

I've cut and pasted the other forum's text here, but can't supply the images, without more effort than I' willing to bother with. It'll offer an idea of what Leo is looking to do.

"The boat I will be building does not have a name. The design is inspired by the Flicka 20, although she won't have such a heavy displacement. The boat plans will be taken from an ocean-proven vessel that's been lying around here (see: measured) then modified slightly to bring it closer to what I have in mind. This figure is not set in stone, but I plan on increasing the boat's length by ~4 feet, and the beam by ~4 inches. The original LOA is 20 feet and the beam is 7 feet. There is a picture I've attached and it'd be nice if someone could get a name of either the boat or the designer. The "cabin" in the picture was added after its owner died.

She will have a fin keel and a ballast consisting, in part, in the form of steel plating. The construction method will be a multi-chine dory-style hull to save time and I am hoping that I'll be able to finish this boat within a year. I will be using Santa Clara marine plywood in between a fiberglass and resin layer on both the outside and inside. The mahogany I have so far is (I believe) of a South American species and will be used for the bow, keel, etc. I am currently weighing the options for a variety of cabin layouts, but advice on that will have to wait until the hull is finished.

The rig, as mentioned, will be junk. I will sail singlehandedly around the world for a long time and the practicality of instant reefing cannot be passed up. I plan on adopting one of the Western modifications to the Chinese junk and I have been loaned a book called Practical Junk Rig by Blondie Hasler, who is extremely well-known in the sailing community. I have yet to finish it, but I have to finish the boat before making the sail anyway. The mast will be made of thick-walled bamboo and I find it very funny that I'll be sailing across the world with a piece of grass (and yes, bamboo checks out).

I haven't bought any plans because I've essentially (under the instruction of my.. teacher so to speak) created a frames view on a big piece of plywood, which I will be using to create bulkheads on which to wrap battens around to get the curve. That sounds a little more complicated than it actually is, but hopefully the pictures that will eventually follow this thread will make it clearer. The bulkheads (the big ones formed by adjoined 8x4 marine ply) will be adjusted accordingly to the plan to extend the length once I finish mapping everything. Since I have no experience it's slow going, although the local boat builders here help me out constantly.

Technical comments, tricks and tips, as well as online resources, book titles and advice are all appreciated. I request that untested and/or unproven theories on so-called cruising conjectured from hearsay and gossip be withheld for the sake of keeping the thread clean and concise. I do not want to be associated with the term 'yacht owner' because I'm not rich at all, and 'modern cruising' always seems to involve motor under sail, navigating by GPS. I do not plan on buying a GPS or autopilot, or using the motor unless I am in a dangerous situation (I will have a wind vane). I do plan on learning everything about my boat from the ground up and how to navigate without the use of any electronics (although I will have limited solar power). That said, questions are always welcome and I don't want to discourage them. Most of all, I want this thread to inspire others to do the crazy stuff they've dreamed about. You just have to be insane enough.

I consider this to be the true starting point of a really awesome adventure, so I'll post what pictures I think are relevant and some numbers for what I've spent so far in both time and money (converted to USD) to get to where I am now. I am keeping the pictures and posts down to a minimum because plenty more are coming. Do note that I am in a country where things are a lot cheaper than in the US and these figures are accurate as I keep a dedicated accounting/daily planning notebook that I write in every night and morning.

You may wonder why I'm including costs such as for my visa extensions, food, household items and so on. The reason is that I'm also trying to get others who are my age to live more adventurous lives without letting money stop them. At the very least, I think the numbers could inspire others to decide to live their lives for themselves instead of for others. I've worked to save up enough to travel around the world and about 90% of what I've spent traveling (including now) comes from those savings. The other 10% is my parents' money that I was required to spend due to them worrying about me. I don't like that percentage, but they sort of forced me into it. And yes, I never went to college because I figured I don't have to spend 8+ years preparing to live my dream when I could jump straight into the fun stuff.

Pictures Explanations:
1. Here is the picture of the original boat I took the measurements off of.
2. Designing the frames view.
3. Mixing cement to create a level rack on which to build the boat. I was loaned an old rack to use, but I had to buy some mahogany (that will later be used on the boat) to finish the rack. You can also see my first project and bamboo workbench. The tarp looks a bit pathetic and I'll be replacing it with a proper (and expensive) one once I finish constructing a bamboo frame.
4. Leveled rack.
5. Four pieces of the twelve 3/8 in. 8x4 ft. Santa Clara marine ply ($331) bolted together with tek screws that will be used as bulkheads at station 1 and 4 (length of extended cabin).

Time:

Clearing land - 18 hours
Repairing dinghy (learning how to use power tools, stitch and glue, apply fiberglass, etc.) - 107 hours
Running around with a measuring tape and spirit level - 13 hours
Land Modifications and Side Projects (bamboo workbench, toolbox, rack construction, etc.) - 41 hours so far
Reading and research (excluding online research and reading, which I spend more time on) - 51 hours so far
- Voyaging on a Small Income by Annie Hill
- Tropical Cruising Handbook by Mark Smaalders & Kim des Rochers
- Storm Tactics by Lin and Larry Pardey
- Practical Junk Rig by Blondie Hasler
Due to the courtesy of others, I have a huge library of books related to sailing. If there are any books you'd recommend, that'll help in locating what I'd like to read and photocopy.
Cane Toads murdered in cold blood (confirmed kills)- 16 total so far
Building main boat - 16 hours so far

Money:

Fixed Costs (more or less):
Land rent - $500 yearly
Accommodation rent - $133 monthly
Visa extension - $60 initial, $150 next two months, $40 monthly from then
Food - $280 monthly
Transportation - $32 monthly
Jigsaw - free (present)
Power Drill Set (complete with hammer, measuring tape, screwdriver set, spirit level and more) - $60
Grinder - $40
Electrical stuff - $30

Costs that will keep rising:
Equipment I [Essentials] (excluding power drill, grinder, electrical stuff) - $200
Equipment II [Boatbuilding Materials] - $425
Equipment III [Household Stuff] - $64
Equipment IV [Others] - $37

Notes:
- The Cane Toads are an invasive species here and the local sport is to hunt the absorbent, squishy, parasitic ******** down mercilessly.
- Transportation works a bit differently due to carpooling and generosity.
- The costs so far are a rough estimate. At the end of every month I do a summary of everything, so more accurate figures will be posted then.
- Thanks for reading so far; I go to town 3 days a week and will update on a weekly or bi-weekly basis. Cheers."

The only real question I have is who is the "designer" you have currently working on this stretch/enlargement?

 

Do you have any prices for boat materials? I understand you have a dream, but do you have a plan and the skills to fulfill it?

 

Sailing round the world in a 20' boat seems fraught to me. Hasten slowly.

 

We've seen this desire many times previously and the logical recommendation is to take a small boat down to the beach and launch into the breakers. Then spend a few hours, working your way through these breakers, as this is what it's going to feel like at times, with a little boat in big seas. This is usually all it takes to convince most that their dream needs to be reevaluated. Can it be done - yep sure can and it has been done a number of times, but it's damn uncomfortable and learning to enjoy the effects of motion sickness can't be ignored.

 

The prices are approximately $313 US for 12 pieces of 4x8 Santa Clara marine plywood, 3/8th inches thick. It costs about $22 US for two pieces of 2x6x8 mahogany (South America, locally grown). The vendors coincidentally are women who have asked me about what I'm doing. They've all given me discounts . I have plans, but I've learned not to rely on them working out properly. I'll learn whatever skills necessary.

Unfortunately, I've started this project with all the insanity and recklessness that comes with all the testosterone a then-teenager could muster. I would like to believe that I am heeding all the advice I'm getting, but in reality I'm probably not. But thanks for your concern; I'll try to be safe.

Hello again PAR. My current experience with sailing is one 7-hour journey on an acquaintance's yacht, not much bigger than what I'll build, steering for about an hour. It's vastly different from what I'll be doing (I won't have a wheel and my rig will be junk, not gaff), but I believe I'll be fine as my only problems consisted of an inability to piss off the side of the boat. Hopefully that'll be fixed with more hours. Motion sickness doesn't seem to be a problem, yet.

Thanks for all your comments; I didn't have enough time last time to properly do this, so I'll do it now.

The link provided in my first post is my build and all the pictures are there. I would like advice to be centered around practical solutions pertaining to the construction of the boat. Numbers and calculations are good, but practical tips and suggestions are better since I can relate to them more. I do have a couple naval architects who have each studied formally for more than a decade who I am relying upon, but the main point of this forum post was to get suggestions on the modification of the old boat to get ideas. Every boat is a compilation of previous ideas and my goal is to get informed of the pros and cons of certain designs.

I know I'm asking something for nothing and I'm not expecting anyone to commit to something that I'm responsible for. I'm already very grateful for all the help I've received so far and I deserve no credit for anything. This is just a shot in the dark to gather as much information as I can to make this work as best as it can. Thanks for reading.

 

Here is a practical tip: can you hit a nail square in the head every time a few thousand times a day? That is a basic practical skill any carpenter has.

 

Most only use nail guns these days. A hammer rarely comes into play. Looking around at my old timber house, I sometimes think of the hard work that went into, I doubt any power tools at all were used, on-site.

 

I very rarely use nails, though I do use a hammer frequently. Working on a tinny recently, I asked the client to grab a deadblow out of my hammer box (I have a box full of hammers hanging on the side of the tall tool box). He wanted to know why I have a few dozen hammers, of all different shapes and sizes. I explained each had a specific purpose, which he found odd until I ran off a few names and reasons for their need.

Leo, as previously mentioned, you really need some sailing time under your legs, before you can envision a custom or semi custom yacht build, particularly if you're input will be the primary driver of the SOR. Simply put, you just don't know what you need or want, other than what you've gathered, in reading other sailor's experiences. There's no substitute for actual experience. Every custom design I've done, has been for those that have a huge wealth of sailing ecperence, whereas their needs and desires, were well defined based on what they've learned. Without this sea time under your belt, your SOR will be based on other folks needs and desires, which will be quite different from what you eventually find is manageable. For example, you seem to be married to the junk rig, which is fine, but you can't justify this rig choice, which begs the question why the odd rig choice, given the huge predominance of other rigs. In other words, if the junk was so desirable, why so few in most of the world? There's a reason, but you haven't the experience to know it yet.

I'd recommend you build Mic Storer's GIS design, maybe converting to junk if desired. It's a simple design to build, offers good performance and you can be sailing quickly. Once you've got a few seasons of hard sailing under her keel, your views and opinions of everything sailing will change dramatically and you'll be better equipped, to establish a reasonable SOR for your custom design.

 

Hahaha I don't think I can hit a nail squarely thousands of times in a row, but I've been getting better. I do have some prior experience with basic carpentry and fortunately sore thumbs are a distant memory. Actually, I've recently had a difficult time trying to nail some very hard wood scraps at an angle, but it turned out to be unnecessary.

I don't think I'll be getting a nail gun; it doesn't seem to be a requirement and will just be an extra cost. I'm already borrowing a lot of tools and materials to save money.

PAR, thanks a lot for that. You've just convinced me to stop stalling. Similar to what you've said, I've been told many times that I should reconsider my choice of rigging, and soon because it'll influence the construction of the hull.

There is an owner of an original Chinese junk who's been hanging around here and I'll take him up on his offer to go see his boat soon. I'll have to go see the German couple as well. To be honest, I've gotten a lot of invitations to go on board some yachts but I was saving it for after I finished construction on the hull (inspiration for cabin layout). Guess I'll have to give it a shot sooner or later.

Questions (I've asked these already, but I would like as many opinions as possible. Feel free to skip questions you don't want to answer):

- How does an extreme curve on the hull aft of the boat (end of cabin to transom) differ from a more moderate curve in respects to sailing?

- How does increasing or decreasing the waterline level on the bow influence sailing, stability and to a lesser extent, speed (I don't care how fast my boat is)?

- What are the pros and cons of extended cabin length? So in other words, what are the pros/cons of a lower/higher ratio of cabin size to the overall length of the boat?

- I would like to be able to stand up in the saloon (I am 5'10), but it may mean that I'll have to raise the cabin by more than what I want. What are the pros/cons of a raised cabin compared to a lower one?

- What are some things I should be careful about in marine ply/fiberglass construction at the beginning so I won't have headaches about maintenance and repair later on?

- Lastly, I was told that I couldn't sit on the bow when sailing because my boat would be too small and it'll affect the sailing. Could I do anything to allow myself to sit on the bow when sailing without doing something stupid?

Thanks in advance.

 

An "extreme curve" is a pretty subjective thing. It's affect on sailing will be two fold; areo and/or hydrodynamic. The amount of affect depends on location and several other factors, so an impossible question to answer without some refinement.

I'm not sure what you mean by increasing the WL level on the bow, but if you depress the bow, you pick up increased drag and wetted surface, which might slow you down and/or cause steering issues, such as stronger rounding moment. Decreasing the emersion of the bow will usually cause the bow to "blow off" a bit, forcing the boat to bare away.

The are no pro's or con's to cabin length, assuming you have the room to do so. You can take this to extremes which can alter the balance of the boat, but generally the cabin can shortened or lengthened a bit without harm.

Standing headroom in a 20' LOD boat is a very difficult thing to design right, especially if you need shoal draft too. As a rule, most people like to lie down in a V berth and sit on a settee, so less than standing headroom isn't as important as you might think. A cabin on a 20' is a small thing, so you clammer below and sit or lie down as desired.

Reading up on the processes and techniques, will save you heartache, lots of it. All the major epoxy suppliers have documentation about embalming wood so it doesn't rot. My site has a little information too.

You can sit on the bow when sailing, but it will affect the sailing qualities while you're up there. The boat will "plow" a bit, but it's not going to sink or flip over, just sail like a gator is clinging to the stem. On small boats (anything under 30') anywhere you sit, stand lie down, etc. will have an effect on the boat. It'll heel a little more or less, might want to steer up or down, etc., but this is normal and should be expected and adjusted for underway by whomever is at the helm. You'll learn all this stuff and much more once you get some sea time under your butt.

 

In a 20 foot boat, you will have about 10-12 feet of length to move around. It doesn't make much difference if there is standing headroom or not.