new kayak project research

Hi all, 

am working out the details of my latest build and wanted to ask any of our forum members about their experience with paulownia.

the remit for my latest boat is very low weight day touring boat.  as i get older, light weight gets more and more attractive.

so the basic idea is something like a petrel play hull with a new deck i am currently designing built out of 1/4 inch or 3/16 inch thick paulownia glassed in 4 oz s-glass.

currently calculating out a total weight of between 26 and 28 lbs depending on some options i am still working through.

anyway, the essence of the question is really about paulownia and 3/16 vs 1/4 inch.  and can i go with 3/16? and how do people see the risk/tradeoffs on this question.

thanks in advance for your thoughts and ideas.

h


33 replies:

« Previous Post       List of Posts       Next Post »

RE: new kayak project research

   Is it available in your area?

Sounds like an interesting wood species

https://www.wood-database.com/paulownia/

RE: new kayak project research

i am in the washington DC metro area.  i am looking at using https://clearwoodpaddleboards.com who sells milled strips that can be shipped within north america.  they appear to be based out of oregon.

 

RE: new kayak project research

I built my last kayak using 3/16" Paulownia strips. I used the paulownia for the hull and cedar for the deck.

I was able to buy 1"x6"x16' paulownia exterior siding at a lumber yard near me. The siding had quite a few knots so I ended up painting the hull, and at that point made the decission to use cedar for the deck. The paulownia worked quite well for the hull and I would use it again as  it is strong, light and isn't difficult to work. 

RE: new kayak project research

hi walt, 

could you share some more details about your project that you did with paulownia....what kind of kayak?  any pictures?  what glassing schedule...how has it held up? 

many thanks

h

 

RE: new kayak project research

Hi folks, 

just thought i would update forum readers on the project i am working on.  may look like i am a forum stalker but have been at my computer all day working on the design of the 'new boat' and looking up a lot of reference material and making some decisions.

as i mentioned, the remit of the boat is a lightweight day tourer sea kayak - inspired by some ideas i have been reading a lot about.   for example, designing to be efficient (fast) at cruising power is not the same as designing to be efficient (fast) at maximum power.  and a boat that is designed to be fast at cruising power is often shorter, counter-intuitively, than a boat designed to be fast at max power.  or another way to think about it is, a shorter boat can be faster than a longer boat at low (cruising) power.  i have also thought a lot about the mission and, notwithstanding all the great adventures i read, about, what does most of my paddling look like? (e.g., i take day trips, and bring a lunch.  i rarely go overnight camping self supported out of my boat).   anyway, when you distill it all down, if I think about it like that, and want to make it easy (e.g., keep the boat light), i think the right answer is a boat that can do the job at ~ 26 lbs without doing anything really fancy.

so i thought i would share a picture and some calculations.

so the first picture is the boat:

the hull is based on the petrel play with a custom deck that i will be fabricating.  i have been doing a lot of work studying the petrel play and i think its hull is the right hull for the job.  i am going to take a little volume out of the ends above the waterline as i am not really expecting to use it in the surf the way the original petrel play was designed.  the orignial petrel play is 14" loa....so this will be about 13"6 with the same waterline but with the ends a little less tall we are going to lose about 6 inches  of overhang and loa.

the next picture is the calculations of the bill of materail weight (e.g.,  the ingredients and their individual weights).  i analyzed a couple different hull buildups and am going with the 3/16 palowinia (hence highlighted in yellow).  the time by the computer today was sorting out all the weights and it suggest a build coming in at ~ 26lbs fully rigged.

anyway, i thought it might be interesting to share.  the last time i built a customized boat i was within a pound of the calculated weight.....so it can be reasonably reliable if you are careful with the math and a careful builder.    happy to hear any feedback.   material has started to arrive so i expect in March the building will be starting.

h

RE: new kayak project -paulownia arrived

as i think about spring coming and it warming up enough that wood glue works (> 50 degrees), my project for a 25lb lightweight touring kayak has started in earnest.   

the other day i picked up the petrel play forms from CLC (plus a couple nice T-shirts that were on sale).  today, my 1000 linear feet of 3/16X3/4X96 inch paulownia strips arrived.   big thanks to Randy Bogardus at Clearwood Paddleboards for sorting through his inventory and rejecting the 'heavies' to mill me the lightest strips.

i was impressed with a really tight packing job and everything appears to have come through shipping in great shape.  my initial impression is the paulownia, compared to cedar is not visually interesting.  very consistent color and grain.   pretty much a balsa wood kind of look....so am curious to see how we will approach the finishing steps and how stain and paint will work with this.

next steps are to buld a new workbench in the garage and get the strongback set up.....i expect the stripping to go faster than usual as, like a lot of folks, i am working out of the house for the next several months  so i can covert commute time stripping time.  

h

RE: new kayak project research

Keep the updates coming.  My next project is likely a Panthera 2 lightly build so that it is easy to laod on my truck.  I might use Paulownia for the hull.    

RE: new kayak project research

   ok....so it's finally getting warm and today i started cleaning up the garage and re-arranging things so i can start my build.  it's a pretty small space i have right now and i have to share the garage with a lot of other stuff during this build.  thank goodness this boat is just under 14 feet long. 

anyway, today i got the strongback out, a work table organized and just starting to get everything where i need it to be able to start.  tomorrow i hope to start getting the forms set up on the strongback.  whoopee!

RE: new kayak project research

it's warmed up here in the DC region and i have started the project in earnest.

the last two days were about setting up the frames and making the adjustment for the custom deck.  this was a tedious process and doing it the old fashioned way with a petrel play hull and a customized, low profile deck.  the low profile deck takes some volume out of the ends but does not impact the general cockpit volme.

the picture below shows the desired profile and a reference line for sorting it all out and a draw-over on the original petrel play hull profile, so you can see generally what i mean by taking some volume out of the ends.

as i mentioned, below the water line, there is no difference from the petrel play but i took some spring out of the shear and thus there is a new shear line and the first and last couple form are signficantly cut back.  for most of the paddling i do which is flat or flat and windy, this should have no negative impact....and probably a positive one.  in trying to hit 25lbs everything matters so a little less volume on the ends adds up to taking about 120 square inches of skin out of the boat and yields back 7.09 oz of weight saving, and less windage.  interestingly enough, the tweak in measurements adds a bit of knee room (about 1/8 inch) and takes out a bit of foot room (about 3/16)

anyway, it was a long day but all the adjustments were made to the forms 

the next picture is what the forms in the bow looked like with some premeasurements in place (prior to cutting).   so these are the original petrel play forms...but the blue tape line shows the new deck profile that i am going to cut and the pink line is the adjustments to deck height on back that needs to be worked in as well.

so after all the tedious cutting.....here is what it now looks like:

you can see in this picture the downsloping deck now along the pink line and the recut bow form.  forms 1 - 5 all needed to be adjusted for the new slope of the deck.

the same exercise was performed on the rear of the boat as well impacting forms 11-14.

anyway, going to call it a day.  but i think it looks on track.

h

RE: new kayak project research

just a quick update on the project.

the shear strip is in....it's a white piece of cedar.

a lot of hours just getting the first strip all perfect and centered and symetrical.  but looks good.

and now for the first strip of paulownia.

so my first impression of the paulownia (3/16" X 3/4" x 8 feet) is that this is very easy to work with and relatively soft compared to cedar.  the wood that i had prepared for me is very clear and even and not visually interesting....but the objective of this boat is light, high-performing, easy to carry.  so now that the first strip is down i should be able to accelerate.  this is not bead and cove....so its a bit slower as each piece needs to be beveled....and i am using Nick Schade's robo bevel tool...so seems like pretty quick work.   

one thing is clear is that i will need to pay very careful attention to alignment and sanding as 3/16 thick does not leave a lot of room for errors and a ros sander can easily bend the wood between forms.   so i am thinking of some creative was to ensure i can get the finish/fareness i need.

h

RE: new kayak project research

i thought a little update would be in order....i have accellerated the stripping and making good progress

the petrel play hull strips pretty fast except to the point you get to in this picture where from about the rear of the cockpit area half way to the back of the boat you have a hard chine that needs a little bit of attention and some careful cutting to get around this corner.  that said, i will make the turn tomorrow and the the bottom then will be relatively quick.

i thought i would comment some more on using paulownia wood to this stage.  first, it is very consistent grain very similar to balsa wood and a bit more flexible and soft than western red cedar.  so i am finding it very easy to work with and the robo plane planes it very easily.  so stripping is striking me as relatively easy compared to cedar.

i am a bit concerned about how easily dented it is pre-epoxy.  i was also concerned a bit with its ease of flex.  but now that i have six strip edge glued and the petrel has a nice curvy line to it, everything is stiffining up quite nicely compare to how an individual strip felt.   i don't intend to bang this boat around as its target weight remains ~ 25 lbs....but i do want it to be able to take normal bangs....so i guess we will wait and see.

on the kayaking front, i am getting out two to three times a week with my 33 lb petrel.  all i can say is making it light makes it really easy to go paddling...so i hope i can hit the mark of a sub 30 lb boat with this modified petrel play.

h

 

RE: new kayak project research

just moving along on the hull.....one half of the bottom to go then we can start the deck.

the paulownia is very easy to work with....i am very interested to see how it glasses up.

h

 

RE: new kayak project research

   Now that you've built with bead and cove, and bevel, which would you prefer?   Is one better than the other?

I'll be using paulownia.

RE: new kayak project research

Hi Ross

Great question.

The first strip boat I built was cove and bead and, looking back at the skills I had at the time, I don’t think I would have gotten a great result if I had tried the bevel technique.

But now I handle a plane like a good musician handles their instrument and turning out a bevel boat is just as easy as working with cove and bead.  I don’t really think about it….i pick up the plane, visualize what I want to do, and it just goes right and the gaps are just as tight as cove and bead.

So right now, I tend to build the cove and bead or bevel technique based on the wood I happen to have acquired.   If its cove and bead, that’s what I will use.  If I am having it custom cut, I usually go with rectangular pieces and do all the beveling myself.

Fwiw, I picked up a lot of my planing skills building my first strip built….even a cove and bead boat requires a fair amount of beveling…..but it sort of eases you into it.  the robo bevel, which I used for the first time on this boat, makes it even easier.  The first bevel boat I built was before the robo bevel.

As mentioned in my remarks above.  I am finding the paulownia very easy to work with.  It does not have the strong grain of cedar….so less tear outs or rough cuts.

Attached is latest picture of the hull.  Closed it up this afternoon and this evening pulled the staples out.  So we will see how it sands up tomorrow.

h

RE: new kayak project research

   hspira

Question, what is a roto bevel?

Had another question, but realized it doesn't pertain to this style of boat building

RE: new kayak project research

   apologies,   i meant to say Robo-bevel.  see the link below:

https://www.guillemot-kayaks.com/catalog/boat-building-tools/robo-bevel-strip-built-boat-beveling-tool

it really speeds stuff up if the tool happens to work for you.  in some cases, the hull shape is such that the tools is not very effective (tight radiuses/curves).  but if you have a lot of straight/long runs....it definitely takes some work out of planing by hand.

h

RE: new kayak project research

   WOW, cool tool!

I can see where that would make things easier

Don't think I'll ever build a strip kayak, but thanks for enlightening me

RE: new kayak project research

i thought i would update you all on the build as i came to an interesting juncture on this boat's construction ...and got to try some things out that i had not done before.

my most recent task was the external stems....and historically, with longer, pointier boats, the stem bends were gradual enough that i could bend wood with, at best, a little bit of muscle,  and at worst, a little bit of heat from a heat gun and some muscle.   but after breaking a couple pieces with these two techniques, i finally surrendered to the realization that this was going to take steam.  and so i dutifully set upon the internet to find a steam box that i could quickly assemble.

after several hours of research i declared myself unsatisfied with the proposed solutions and started about rummaging throuh my favorite place (and my wifes least favorite) the kitchen,  for a solution.

i was greeted with a 'what are you cooking?' (her birthday's tomorrow.....) and promptly and proudly (becuase i spent no money) displayed that i had conscripted our turkey roasting pan and steamer platform into boat building duty and was happily 'steaming'  the cedar strips for my stems.

this did not prompt any particular reaction from my wife, but as she realized this had nothing to do with her birthday, she quickly lost interest and returned to her hobby playing with the family cats....refusing my entreaties to engage her in a conversation about everything i had just learned about bending wood and how it was so similar to cooking brisket.

anyway, enough about the family....

the next picture shows how relaxed the wood became after about an hour of steaming (hence the brisket analogy) so i temporarily held the pieces on the stem forms while i busilly attached their kin to the boat:

and here is the final step with them now attached to the boat:

anyway....the goal tonight is to start to fare these stems in....and work on overally sanding of the hull.

in summary, a turkey pot is a great way to steam small wood strips without making an investment in a specialized steam box.

h

RE: new kayak project research

time....for an update.  its been going a bit slower than i had hope.  part of the challenge is i don't have my regular work shop and very little room....so i have a lot of re-arranging of things after each step.

also just trying to be careful as i a key objective of the whole project is to see how light i can build - target 25 lbs...and so you have to be careful.

anyway, this is the hull after sanding and faring.

 compared to cedar, you can see that the paulownia is not particularly visually interesting.  it has a very much balsawood kind of grain and color.   i also had to take some extra time sanding it with very new/clean sandpaper as i am only using 3/16 strips, so they bend if you push them....you need your sandpaper sharp and just need to be carefu.

i have not totally sorted out how i want to finish the boat...i have been thinking about painting....but i also know if you want that stained look, its got to go on under the glass.  so i have elected to take a bit more time and stain it with my signature look (see the night heron in the pictures) so i have the option to do that or can paint over it if i want.  so that ate up some days.  interestingly, it stains well but is more difficult to stain than cedar becuase since there is little color difference in the strips themselves, you have to be a bit more attentive to the stain density across the entire boat for it to look nice.  with cedar, the variation in color in the underlying wood means you can be a bit looser on the stain consistency.

anyway, stained, and applied 4 oz s glass and will complete fill coats tomorrow.   the s glass is pretty expensive stuff so i am also being vary careful laying it out and minimizing wastage.  i bought only 10 yards of 60 inch wide so have to get both a hull and deck piece/inside and out so the material needs to be carefully cut in its width with little wastage to make it all work.

for lazlo, if you are reading this, you can see my white sheer line and stem lines which is basically just carefully masked off stain.   worked very well on this.

i have also been measuring all the epoxy used so far....and seem to be on track for the calculated weight.....

h

RE: new kayak project research

  flipped over and  started working on the deck.  so far, so good :)

RE: new kayak project research

I'm not intending to hijack your thread hspira, but this is the progress on mine after about 45 hours work, including cutting forms and mounting on the strongback.

I'm working on the recessed cockpit today and will also fit stem and stern pieces.

 

RE: new kayak project research

 Howdy, 

been off-line for the better part of two months between some family issues and moving to our new house (still in the DC area...but now on the virginia side :).   

the movers were eager to show me that they could move my project and i was pretty exhausted....so i let them.  it got here just fine and today i started work again.  the step today was i put the cockpit apron in which was a pretty interesting piece of work.

this is actually the first time i took a precut cockpit apron and installed it on strip built after the deck had been stripped...so i found cutting the cockpit opening and fitting the apron to be a pretty time-consuming piece of work.  but it's all good now. 

this was also the first time i used cryanocrylate glue with the accelerant to tack weld (which is how i attached the apron).  don't know why i waited so long to use this technique.  really works well.   now to see if i can get moving again fast enough to finish this boat this season.

still on track for a total weight of 25 lbs....so am very happy with progress so far.

Ross, on your build which you posted above, i can't see any of your pictures.....maybe you can try again.

h

RE: new kayak project research

The pictures are coming up for me, so I don't know what's happening.

I'll try posting the latest in a day or so.

RE: new kayak project research

RossM,

The actual server error is:

{"error":{"code":"EC-4008","requestId":"68a69300-e3cd-11eb-c000-7187066d7030"}}

The images are stored at:

https://apis.mail.yahoo.com/ws/v3/mailboxes/@.id==VjN-NojBQ4LpyMq2ACDBEVvBun5OAyqkoiBBGou9JQi8tnMQdIj-LABTeWL_XZdZ9ZlqHZaDHvUEGGFvhGTyyrEl4g/messages/@.id==AFCikBAJ0gnGYNO-AQjdiIdIzaU/content/parts/@.id==2/thumbnail?appid=YMailNorrin&downloadWhenThumbnailFails=true&pid=2

It looks as if you have linked directly to an image in your mailbox. Of course you can see them because it's your mailbox. We can't. You need to rehost your images to a publicly accessible platform if you want others to see them.

Laszlo

RE: new kayak project research

   Thanks Laszlo.    I'll have to upgrade my computer skills!!   

RE: new kayak project research

thought i would provide some updates on the project.   i am starting to progress again after dealing with a death in the family and a move to a new house.   today i locked in the deck color which is a bit unusual....and if it does not work out, we will resort to paint.

in a nutshell, i am breaking free from my signature dark reddish brown hulls and going for a white pickled deck that will have some mahogony accents and a dark stained hull.   the challenge was finding an epoxy- compatible white coloring.  with some help from nick schade and some other chemical research to point me in the right direction.... and a test piece that confirmed (hopefully?) the compatibility with epoxy, i committed tonight with the whitewash of the stain and a skim coat of epoxy to lock it in place.

i have been doing a little summer paddling and the heat buildup on my dark builds when they are in the sun is incredible.   feel like i can cook an egg on the deck....so i would like something that runs a bit cooler and, hopefully, will be visually interesting.

my hope is i can be on track to at least paddle it towards the end of the season if i can start to maintain a pace.   i have also bought a set of maroske fittings that i am going to try out and will report on how that goes.

while i am working on the hull, also working on a carbon fibre skeg for the new boat.  its a bit of a process but looks cool and a very inexpensive, bullet proof, easy build.  below is a picture of the bits starting to come together....still some work to do.....but a nice side project while working between other steps.

still on track for an overall weight of 25 to 26 lbs....so watching all that carefully.

h    

RE: new kayak project research

   I appreciate the ongoing commentary and beautiful work here!

With your focus on weight, I thought you should know the quote from Antoine St. Exupery (best known as the author of "The Little Prince") who said (in French - so lousy translation, probably):  

  "The design is not complete when you've added everything you need; it is complete when you've taken out everything you don't need."

He was an aviator (and designer) in the early days of flight; ounces mattered! 

RE: new kayak project research

It's been a couple weeks and thought i would provide an update.  since i had my last post i lost a week out in los angeles but am now back at home for a 30 day stretch so diving in again.

my target right now is to finish the underside of the deck while i keep the hull safely on its forms.   tonight i finish a skim coat of raw epoxy follwed by a skim coat of west systems 407 filler to fill in any imperfections in the underlying woodwork - this helps keep the boat light and makes the glass work which i will do tomorrow night very fast and easy and with little if no voids (little un-wet out glass strip) because the wood is sealed as well as any little gaps have been filled.in addition, in shorter sessions i have been building out the bits on the inside and for hatches and skeg.

here is a close-up of the skeg with a carbon fibre blade and paolownia housing:

i will be doing a check-in weigh- in shortly to see how i am doing on being on task with respect to the 25.5 target weight for the complete boat.  i do have a bit of a concern that the 3/16 paulownia hull is a bit more fragile than i want in certain areas.....and may address that issue with some addiitonal glass beyond the planned layup in the cockpit area.   my plan, as mentioned above is to treat the boat carefully like a rowing skull....and i am trading the convenience of a light boat with an understanding that this is basically a flat water boat.   but i don't really have a sense of things while the boat is still on the frames and with only one side glassed....so we will see.

in the meatime, i was also able to get a paddle in before Ida blew through the other day...

24 hours after this picture, the river rose almost 5 feet in this section and my access point was closed off.....   so stayed in the shop and worked on the new build.

h

RE: new kayak project research

   so the deck underside got glassed per schedule....had my timing a bit off so i was up at 1 AM and again at 6 AM to finish this work;

above is the picture after the glass work.  a couple things to note if you have been reading this thread, 1) the glass i am using is s-glass....a signficantly stronger and substantially more expensive material than e-glass (which is what a normal kayak kit ships with).  so i am very careful to cut to minimize wastage.  i only ordered 10 yards 60 inch wide for the entire boat.  so each 5 yard section has to do a hull section and a deck section.leaving only about 3 inches of extra down the middle at the widest point.  2) i am working on building light so i was very attentive to my skim coats and ensuring i had no holes or crevises that would fill with straight epoxy....and have been using a putty of west 407 filler for the little fillets and gap filling.

the next picture highlights that i want to be careful to wet the glass out....but not try to fill the weave.   this is the inside of the boat and while there will be some more reinforcing glass around the cockpit area, i am trying to minimize epoxy weight.   so using the light to help highlight that i have the glass wet out but not pooling epoxy (adding unncessay weight) is an important part of the process.

the deck for the next 24 hours is now taped back to the hull to ensure the shape is held while the epoxy completes its cure.

h

RE: new kayak project research

It's a quiet, rainy day here in the DMV...so my project is getting a bit more attention than expected.

i am going forward with getting the deck ready....and then will come back to glass the inside of the hull when the deck is pretty much all set up.  the hull is nice and safe on the forms...so no issue with the wait.

today i am working on the coaming.  a bit of information to share for petrel play strip builders....CLC can sell you the coaming risers and coaming from the petrel play stitch and glue.....and it all fits the coaming sill for the petrel plan strip build that comes with the all woods part kit.  this way you don't have to (if you don't want to) make risers and a coaming from strips.  anway, i thought it looked cool and did not have a particularly negative impact on my desire for weight.

so here is glassing the underside of the coaming before it is glued to the risers:

   

and here are the risers (this is a stack of 4 pieces of 4 mm okoume cut 1/4 inch wide (so same width as 1/4 inch cedar)  and this is all glued to comform to the hull....but not glued to the hull yet as there is a layer of saran wrap right now between the hull and risers.  this way i can remove the risers and clean them up very nice.

the other thing i would highlight which is relevent to hybrid and strip builds as well as shearwater builders, is that when i do this, i have the deck taped temporarily but tightly to the hull.  this way, as we add structure to the deck, we ensure the additional structure (coamings, hatches, etc) are holding the deck in its correct shape vs taking a misalignment and locking it in.  makes for much easier final assembly.

h

RE: new kayak project research

   oops....looks like i pasted the wrong picture in the second picture:

the other thought i wanted to share on this build is that i did want to ensure that the coaming/risers and sill area would be strong and that is also part of the reason i decided to stay with okoume here.

h

RE: new kayak project research

another quiet day and pondering a lot about layup schedule....and balancing light with not too fragile.   and re-assessing how i want to handle fittings and deck hardware.

i have almost finished the deck and thought i would do my first interim weigh in.   at this point i am a bit over 7 lbs for the deck fully skinned on both sides and coaming installed.

i am expecting to add between 1 to 2 lbs to complete this section,  most of that weight is going to be in hatch hardware and deck fittings.  plus there is a about 8 oz in some final reinforcing glass on the backside of the deck around the cockpit.

overall....easily on target for sub 30 lbs....    just depending on sorting out fitting options on where that will place me between 25.5 and 30.

h

RE: new kayak project research

thought i would provide a little update on the project.  the last two nights i cut the hatches and tonight will glue in the spacers and platform.

for this strip build i took the liberty of buying some pre-cut pieces special ordered from other designs to help me with places that i did not want to build up from scratch.   the two areas i went for were the cockpit sill, risers and coaming and hatches which i like from my night heron experience.  i was thinking about different hatch experiences i have had and trying to sort out looks, weight and water-tightness and have found that the night heron hatch set with six toggles per hatch can look real nice in a wood build, are incredibly water tight and not too heavy when you weigh out all the components.  my previous boats have been combination of straps vs toggles....and toggles win hands down for creating really tight waterproof hatches....   anyway, here are the pictures.

the first picture is scribing the hatches uses the spacers to help keep everything aligned.

there was a lot of time pre-fitting everything before i actually started cutting carefully 100% by hand with a japanes bonsai saw.....

and here after a couple more hours is after the cut:

the cuts were pretty clean and i was happy.....just went very slow and carefully.

the other thing that was happening along the way was marking the rigging, bulkheads (will use minicell bulkheads are about 3 inches thick) and footbrace locations and skeg actuator.....to make sure that the location of all of them do not accidently interfere with one another...before the hatches are cut.   this is a bit of the planning that needs to be done when you are customizing ......have to think ahead to the finished product to avoid problems.    the white stain also introduces some challenges about order of operations to preserve it in places i want that color.

anyway....that's the update.

h

« Previous Post     List of Posts     Next Post »


Please login or register to post a reply.