Critique This Hull

Looks like there are some relatively flat areas in the middle of the hull and toward the rear. If there are, you might want to round them off a little. I built one shorty (12-ft) that was relatively flat around the middle (under the cockpit) and that caused the primary stability to be shaky at best. I eventually cut out the chine and installed a new panel to round the hull a little more...stability was improved quite a lot. That said, if you are going to be using an outrigger I suppose stability isn't quite such an issue especially since it will act as a counterweight for the opposite side. I do see more drag with that fat flat stern. I have never built an outrigged kayak before so I could be way off target with my thoughts. Hope I said something that might offer you some food for thought. There are others here who are engineers so they can likely offer you better feedback that I have. Design looks interesting though. What's with the idea of using ballast? Is that for balancing when only one paddler is on board (looks like it fits two, especially if its 25' long with a 30" beam. 

Robert N Pruden

180 lbs with the outrigger and a way to flood it for ballast?

Will you be using a 12 hp diesel? 

I think you have a good idea of what happened; I don't know what I could add.

"Excessive confidence" indeed. I see this occasionally - people who think that (without any experience) they can design something much better than anything that has gone before, something completely 'different'. If it works they are 'visionaries'.

I'd file that design with the magic carburetor that allows cars to run on water.

...but maybe not design them. Ideally, you want to minimize water contact with the hull, the flatter the bottom of the hull is, the more drag and lack of responsiveness you're going to get and the more difficult your experience paddling the thing will be. Take a look in the boat design archives at this site, and read through the builders section of the archives as well, you will learn everything you need to know about exactly what style and type of boat you need. I started out knowing absolutely nothing about building 19 years ago, now I intuitively know what I want and how to build it. By studying the shape of kayaks posted at this site, you will come to understand what I mean. My flatter bottomed 12' kayak was sluggish until I redesigned the hull and made it rounder. Once done, it's stability improved and it handled much better. 

Do you really need a 25' boat when 20-22 ' might work better? A 30" beam sounds fine but it will be a struggle for one paddler to manage, so a rudder will help. A keel that broadens out quickly and forms into a shallow rounded hull will offer up good stability while allowing for reasonable speed and improved turning...with a rudder. Look at Nick's 18' stripper Night Heron, it offers decent speed, excellent turning ability, and excellent stability for such a narrow design...I know, I use the S&G version and love it. Waters Dancing (search it online) has a 22' double that looks beautiful, offers excellent stability, decent speed, and needs a rudder for turning because of its length. 

I hope this gives you a little more insight. Also chat with guys like Jay Babita, Rob Mack's, Nick Shade, etc, etc, they know their stuff and build some of the world's finest boats. 

Robert N(ever say you can't) Pruden

I think CA139 has already stated that he/she isn't interested in building a boat, but just wants an explanation of why his 'friend's'  design  (that he posted in the first post) performed so poorly.

I'll re-state the obvious: That boat has little in common with any human-powered craft, and definitely nothing in common with any good kayak design.

CA139 - Almost all boat building relies on the successful designs of others to build upon. If you want to build a dory, you can buy, copy or slightly change the design based on previous dorys that exist. Its just the way the world of design works. Automotive manufacturers own all kinds of automobiles from other makers to analyze. So, don't give up the desire to build based on somebody's experiment. Chalk it up as experience and move on. We all learn by our mistakes. Best wishes,  - J

That design looks to be the worst I've ever seen. I designed my own double and while building it would often carry it down stairs to do work outside so obviously it was under 25 kg and about that finished. A few months after its first trip it did a 38 day trip circumnavigating Vanua Levi, Fiji followed by a lot of other trips around our local shores.

If I design my own kayaks I know I can depend on them. It makes an interesting project for a couple of months of evenings or if done at work, filled in lunchtimes.

The advantage of plywood kayaks is they are tough and light where as plastic kayaks are tough and heavy.

Plywood - I've dropped kayaks from off the roof of a van on to the ground - no damage.

Rocks - I always hit rocks when out paddling. Dragging up a rocky stony beach? My partner always does - leaves grooves in the stones as the keel has carborundum in the epoxy. We live by a rocky peninsula so just about all the beaches are pebbles or boulders.

Weight? Under 20 kg.

Price? $600 - $800 and that includes all the gear such as rudder, hatches and decklines.

Once plastic gets scuffed due to hitting rocks or dragging across them it is hard to get a smooth hull again. AND plastic is heavy, up to twice the weight of a plywood hull. Any damage to a plywood hull can be easily and cheaply fixed.

NO. I never cover the plywood, out or in with fibreglass cloth.

Possibly the only problem with all of that is I design and build just about everything, hulls, rudders, pumps, decklines, etc. etc. plus a lifetime off and on at sea.

 You can't drop them (for the most part). You can't beach them, land them, or launch from rocks. 

I don't think you should generalize too much from very light glass kayaks like the Stellar, to all fiberglass kayaks.

A glass kayak can be made tough and heavy. The glass kayaks that the Tsunami Rangers developed were very heavy, designed for playing in rocks and surf. A round Vancouver Island record was set some years ago using a Stellar kayak. At one spot it was pulled over a log on the beach, with gear and water/food inside, and it split along the hull-deck seam. The boat was  repaired and finished the circumnavigation in record time.

I land and launch pretty much where I want with my Mariner kayaks. I pull my glass Mariner Max over logs with a load inside with no problems. It's not fair to expect a 30 lb boat to perform like a 60 pounder.

"You have to be careful. But while you can count on plastic to be indestructible, a boat only weighs 25-35lbs for a single and 55lbs for a double "

There are no plastic kayaks as light as those lb figures and usually heavier than that in kg. Paul Caffyn (circumnavigations of Japan, Australia etc.) going for ultralight was getting down to 13 kg fibreglass/kevlar (not plastic) but they were reasonably fragile.

A normal single plastic kayak will be up to 30 kg / 70 lb. They are high-density polyethylene (HDPE), and it is an extremely difficult material to repair.  ABS will be lighter but not as tough.

So we are back to tough, light and repairable, use plywood.

We paddle year round in the PNW area.

My expedition boat is wood/glass with a brass strip on the keel and graphite coating the bottom. I paddle this kayak through and over heavy river ice, logs, bump rocks, drag it over sand and gravel, and have portaged it completely loaded with gear (total weight about 160-lbs) by dragging it through tall grass, over a gravel road for 50 meters, and along dirt trails. No damage beyond the usual surface scratches...no gouges, no cracks. Yes, you can punch a hole in the hull if you bang it the wrong way...but you have to try...and if you do damage it, it's a real easy fix. Even in the field, a badly damaged hull can be patched with glass or just duct taped with good, permanent effect. My expedition kayak weighs 52 lbs mt, a similar plastic boat is over 80 lbs mt. I'll take wood composites every time.

Robert N Pruden

"Plastic will always have a place in my heart just because it's the easiest and you don't have to worry about anything. While you can't repair plastic my attraction to it is that you can't suffer any damage that needs repairing over the lifespan of the plastic. Eventually you'll damage the hull from scratches but by that time it will dry out and become brittle and you have to throw it away anyway."

Lifetime of the plastic kayak? 10 years? So after about 10 years you throw away the plastic kayak. Plastic, the stuff they are complaining about people throwing away. My oldest plywood kayak, built in 1983 and is as usable as the day it was built. Life? Possibly 100+ years.

"...with a wood boat the best you can do is to make it as good as the store bought ones"

Do you want a poorly designed store bought kayaks? I'd class the Seaward one we used in the Queen Charlotte Islands as not the best and the Puffin was always a bit of a dog of a boat. Do you want a well designed kayak? A wooden one can easily be better.

"...the extra weight in a big plastic touring double gives them a nice "recreational" stability."

My double would probably be half the weight and I would expect far more seaworthy. I know I'd definitely trust mine in really bad conditions and not your plastic one.

So you don't know how to build a kayak? OK, but a lot of people do. I've designed and built a few. My partner built her own one. I know that if she'd wanted one my mother would have done a very good job, better than me.

There are good and bad kayak designs in any material.

A plastic Romany  would be an example of good a boat in plastic, and there are other plastic boats (Dagger Stratos, WS Zephyr, etc.) that are well-known as excellent play boats for banging into rocks. PhilipAK has done some very big solo trips in his plastic Nordkapp.

Unless you are very skilled (or lucky), designing your own kayak is in the same category as acting as your own lawyer (or surgeon), for me.

We don't all have Mac50L's skill.

It's rare to hear somebody admit that a boat they designed isn't very good - and that's true for commercial and amateur built boats, as far as I've seen. On top of that, few owners (and especially builders) will speak poorly of their boats - ruins the resale value!

"Not building a boat when you've gone kayaking once or twice in your life."

The first two I built were before I'd gone kayaking. I wanted to explore an island that I'd gone to a couple of times in a yacht. I couldn't afford a 30 foot yacht but could afford a kayak if I built it. The first one was for my daughter's 10th birthday and one for myself.

Because you asked -

"I wonder how those boats paddled"

I did a few years in the first one, built in 1983 and others have used it too. I've still got it. It did a lot of multiday trips.

"I am fairly confident you did your research in terms of what at least some standards were in the world of paddling and looked before you leaped."

No.

"...and more importantly, if you spent a level of funds that was many times the multiple of what an equivalent boat would cost."

Absolutely not. With a Scottish heritage, make it and everything else as cheaply as possible. BUT, make sure you design it to work better than a commercial version. Kayak cost? About 1/3 to 1/4 the cost of a commercial equivalent.

"The other thing I wonder is if your first boats were designed from scratch or were kits,"

I was looking for plans and found someone with very poor blueprints and he'd built from them. I took the basics and modified them to suit. The next kayak, a few years later I ran a building group and we built 4 to a modified and bigger version of the first one.

A few years later I designed and built a double. A few months after its first trip (no prior testing before the first multiday trip) it then did a 38 day trip round Vanua Levu, Fiji. It did a lot of trips with different crews and others using it.

The next was a tortured ply design while my partner built the first of the current design, possibly 50 of which have been built around the world. She still uses it 2 decades on. I eventually built a narrow version for short, light, women. I can only claim to be light.

That's the kayaking part of my maritime history.

Would first going to sea at about the age of 5 years old help? By the start of my teens, teaching myself how to rig and sail a dinghy (no one to teach me). Multiday cruising a Flying Dutchman Olympic class dinghy. Yes, a two man dinghy and your crew should be 6'6" and 200 lb at least. Crewing and racing 30 - 45' yachts.

Yes, it all helps to understand that water is wet.

"It sounds like you had a much better understanding of what needed to be done and started with already a good skeleton in terms of plans."

A lifetime of being at sea, especially both shallow and deep water, sailing small dinghies, meant a bit of understanding of what was wanted and how the sea acted.

"My preferences have more to do with the forest, archery, hiking and guns"

No forests, a bit of archery as a kid and no guns. As I say, we're lazy, like to sit down. Sit on a bicycle or kayak. Bicycle, the longest tour 3500 km up the west coast of California. Here a typical summer holiday used to be, after Xmas, jump on the bike and ride just under 500 km, go kayaking for a week or so and then ride home. Those trips were when I was about your age as I'm close to twice your age now.

"the sea as it's so cold!"

How cold? Here about 10C in winter, up to, if inshore, maybe 16-17C in summer. Where I was brought up closer to 20C in summer. As a teenager with my brother, launching on the mudflats on an outgoing tide, bare-feet and frosty ice, to go out to the open sea for the day. Rules were, "home for dinner" and "don't drown yourself". We obeyed those otherwise we might not have been allowed to go again.

"I have a semi dry suit which helps"

Just neoprene shorts and jacket here.

"I am 6'5" and 190lbs."

Just under 6' and 70 kg (156 lb)

"Good to very good shape but not excellent,...if I ate this way when I was 20 yr old I would look like a greek statue. I almost did,"

If I stood sideways, you might not see me, especially as a kid.

"but I looked (and felt) a lot better 20 years ago trying far, far less hard. Getting old sucks."

See what it is like another 40 years on.

"Given your knowledge base just curious why you think the design I posted is the worst you've ever seen?"

Looks far too high and the drag from that stern would just about stop you dead in the water to start with. The aft bottom is OK with a powerful outboard motor but we're talking kayaking and all conditions, not just running before waves or surf.

Weight, 155 lb !!! I'm talking about just over 1/4 of that weight for mine.

Fibreglass - I've never covered a hull with fibreglass, just the seams. This means, if ever needed, easy to repair and light. Okoume is a tough plywood but heavy. I've gone away from using it.

Cockpits - those are canoe cockpits, not sea kayak cockpits.

The front cockpit breakwater - that's a 1930s thing.

Your comment, "It paddled like a lead sledge, felt like the boat was rooted in cement." is about what I'd expect.