Building a plug

Places, technique, kayaks, safety, the sea...
Post Reply
Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Building a plug

Post by Boatsie » Fri Feb 01, 2019 8:24 pm

Hi. I had paid complete and ordered a 5.5 metre plumb bow sea kayak 2.5 years ago but it looks like I've had the earnings taken and no product will be supplied so I figure I might as well build my own!
About a year or so ago I bought a 2nd hand VFT R. Elliott and that is a boat that suits most days with me. It is fast enough to make way against the tide but because it has a cockpit that extends to the bow I will not be playing in the offshore chop in her.

Hence a quest I on.
With much big foam blocks in the shed. If I was to use a strong back with spaced wooden bulkheads as to the start of a plank strip wooden build but glue the foam between each and then shape the foam to match the shapes..... Would that work?
Not into plagiarism.. Haven't enough effort into design yet but have started.

User avatar
Jim
Posts: 13818
Joined: Sun Apr 21, 2002 2:14 pm
Location: Dumbarton
Has thanked: 4 times
Been thanked: 33 times

Re: Building a plug

Post by Jim » Fri Feb 01, 2019 8:44 pm

Yes, as long as you seal the foam properly when you are happy with your shape.
Some manufacturers use CNC routered foam as the basis for plugs and prototypes.
You will need to sand and polish the sealer to get the actual surface of the plug.

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Fri Feb 01, 2019 9:44 pm

Thank you..

Im thinking that a layer of cloth would seal the shape prior to sanding the plug smooth.
Wondering if foam maintains shape as same as wood was my main concern.
Giving it a go soon.

Chris Bolton
Posts: 2744
Joined: Sun Aug 22, 2004 11:33 pm
Location: NW England
Has thanked: 22 times
Been thanked: 62 times

Re: Building a plug

Post by Chris Bolton » Fri Feb 01, 2019 10:06 pm

Have browse here, Boatsie. I'm sure Google will find more experiences. I've only made a small outrigger float - good luck, but don't underestimate the amount of sanding, filling and polishing you'll end up doing.

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Fri Feb 01, 2019 10:47 pm

Thanks heaps Jim, Chris.

I usually don't finish my projects but I'm guessing with this 1 to be done in about 4 years. :)

Thanks.. Glad to read that foam wood combination should layer okay. Saves me lots of weeks.

Aled
Posts: 296
Joined: Fri Jan 24, 2003 12:40 am
Location: North Wales
Has thanked: 2 times
Been thanked: 13 times
Contact:

Re: Building a plug

Post by Aled » Fri Feb 01, 2019 11:23 pm

Is the foam polystyrene or polyurethane?
If its polystyrene then only use epoxy as a resin to wet out the fibreglass cloth i.e don't use polyester or vinylester resin - they contain styrene which will react badly with the polystyrene and dissolve the foam.
If its polyurethane then you can use epoxy or polyester/vinylester.
Any of the foams will become dimensionally stable when surfaced with a resin impregnated cloth. Ordinary polystyrene foam with one layer of 200gsm (or less) woven cloth becomes surprisingly stable, put 3 layers on and it easily becomes robust enough to make a plug. Multiple layers of thin cloth will drape easier than a stiff heavier cloth - see YouTube videos of surfboard glassing with a squeegee.
Getting the whole plug straight and twist free at the start is the key to success - the strongback and bulkheads will help with alignment, especially with a string line and/or laser light.
Initial foam shaping can be done with a Surform or power rotary sander with 40/60 grit paper - to get the final shape use 60 grit sandpaper on a floorboard or plank and finish by hand. The plank or board could be between 2 and 3 feet long and as wide as the sandpaper roll - you'll feel bumps that are invisible to the eye. Long smooth curves by hand can only made by using a long shaping tool...

User avatar
mick allen
Posts: 12
Joined: Thu Sep 30, 2010 5:26 am

Re: Building a plug

Post by mick allen » Fri Feb 01, 2019 11:32 pm

That approach is really tough to shape and especially finish shape with all the hard wood sections interrupting the much softer foam sections in between - might be better to use 25-50mm thick foam section shapes so everthing handles similarly when getting down close or just smoothing everything a little deeper than you really meant to originally, heh heh.
But as making a plug is so much work, what about spending a shorter length of time just building a decent strip plug? it's almost automatically faired because the wood bends in a fair manner, sand out the small edges, and if you take just a tiny bit of care the plug is a boat also! . . . and then you can choose your pleasure: turn it into a plug with flanges or paddle it first and if it's ok, then turn it into a plug and make it the proto of what you really wish to do. That's actually a time tested approach.
bcmarinetrails.org - 27,000 km of BC coast camping

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Sat Feb 02, 2019 12:23 am

Thanks Aled, thanks Mick.
My mate left heaps of foam blocks and I might as well use them..
Wasn't sure which way would be more entertaining, educational and time effective. Probably is quicker, easier and cost effective if I build a saw table and a boat rather than just a plug.
Guessing the walls get insulation soon. :) thank you..

User avatar
Ceegee
Posts: 965
Joined: Tue Nov 21, 2006 9:32 pm
Location: Mallorca North Coast
Been thanked: 2 times

T

Post by Ceegee » Sat Feb 02, 2019 12:56 am

To be fair, making a plug, then a mould, which needs to be particularly robust (tool coat or thick gelcoat, 5+ layers of CSM, reinforing ribs and flanges) is a LOT of work if you are just making one boat. building a nice cedarstrip is about the same work as making the plug alone.
Cheers,
Steve C. G.

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Sat Feb 02, 2019 5:46 am

True.. I'd be looking at building a handful hence a plug.
The planets hottest ever recorded city is now officially the city where I live. I get dumber sometimes.. Not used to using the air-conditioning I had been using the heat cycle during the heat wave, daily waking in a pond of sweat and stupefied into believing I was cooling the house although such was always hotter within than the outside temperature. The last weekend after 2 weeks ended with recognition of the cooling cycle and basically laying in a bath head aching all day to attempt to feel well.
Remembrance of plan followed which was the purchase of a fast sea worthy boat to please me and if of high quality a follow up a few years later to have built to suit a lady. That boat fell through. I'm guessing the bloke found hardship.
I dislike glassing because many years ago my friends past father fell ill to resin poisoning; he was a career boat builder/ fibreglasser.
Hence the biting of the bullet. So tempted to organize cedar strips but I'll still have to resin and cloth a girl hence the want to get it out of the way and build a mould of which could be vacuum sealed when building a hull.
I don't know if my thinking is correct and I don't want to copy another.
I couldn't figure out why a 1963 fiberglass 4metre sea kayak in the shed was tracking, accelerating and easily holding pace with my 5 metre boats. Started looking.
Glass weight and rigidity was far superior to the plastic hulls. The plumb ends increased her overall waterline length. But what I thought was the clincher was it's stability with width and more importantly a mid section flat plane that transitioned smoothly fore yet sharply aft. Hypothesis suggests that beyond displacement when the bow appears to sink due to returning water being of slower flow than the water pressure pushing the wave, the aft section might react like a water catch and preasurize hence assisting propulsion forward.
Then noticing a Taran 18. I wanted 1. I'd love 1 yet I'd prefer locally built. I visited Rockpool, I admire him although I don't recall name. November 2017 when the mountain roads flash flooded during a half hour hammering was when my uncle and I drove through a metre deep cross current flooding (in a rental 4wd;) all sweet) and then down the slopes into Anglesea to visit and show appreciation. We also visited Peter at NDK and his boat looks playfully serious too but Rockpool Taran had my imagination. Not does she remind me of the 1963 girl but she also does it sidewards; probably to cope with stabilizing side forces at her much longer length. There is more that fascinates me about her yet I've written heaps already.
I admire you guys that paddle such areas because I hate being cold and wet but can see that some of your boats shape use of hydrodynamic forces with much more than just the hull.

I'm loving kayaking too. I have an offer to drive me 100 km down the coast once a month. Will probably buy a second hand boat such as a Sea Leapord or a Sea Bear or similar before I am anywhere near completion of my boat.
The only thing I'm near certain of with this idea is 5.5 metres, 55cm, plumb ends, an aft of plane collector and rocker which will probably be high.
I don't know how to thank you guys/girls.. I'm usually just a retard.. Hence without the need of offshore clothes I still haven't organized that from an enquiry 2 years ago.
Just enjoying paddling on flat water and playing in surf.
I'm honestly dumb... In no rush to build.. Room to slowly make a piece of furniture. 2 years? 5 years? Doesn't matter. Health is wealth. Hence I'd rather be paddling.
Much appreciated fellow waterway users. Much appreciated. Either way will form.

User avatar
Ceegee
Posts: 965
Joined: Tue Nov 21, 2006 9:32 pm
Location: Mallorca North Coast
Been thanked: 2 times

Re: Building a plug

Post by Ceegee » Sun Feb 03, 2019 11:07 am

Worlds hottest city??? Probably best to build in the winter then :) even in our mild summer's a 1 lb pot of resin can go off in 10 mins.

You could do worse than build a nice cedar strip and take a mould off it. That way the plug subsequently serves as a boat too. Check out http://www.etiennemuller.com for inspiration.

Or if you are into hard chine Greenland style, how about a stitch and clue ahrike and take a mould off that? Check out Nick Crowhursts threads, but you had better check with him first if you were going to make a mould/multiple boats, intellectual property and all that (his plans are free but i imagine it is intended one-off own use - best ask).

Yes, the Tarans are lovely boats and Mike W is a true craftsman, build detail and QC are great. I have 2 Rockpools.
Cheers,
Steve C. G.

mcgruff
Posts: 63
Joined: Thu Dec 07, 2017 1:06 am
Location: Scotland
Has thanked: 14 times
Been thanked: 17 times

Re: Building a plug

Post by mcgruff » Sun Feb 03, 2019 2:10 pm

Boatsie wrote:
Sat Feb 02, 2019 5:46 am
The only thing I'm near certain of with this idea is 5.5 metres, 55cm, plumb ends, an aft of plane collector and rocker which will probably be high.
Have you seen the Epic V6? For a short, fat ski with only 4.88m length the performance is surprisingly close to much longer boats.

The potential of a longer waterline is only realised when you pump up the power. A shorter boat with a good hull might be easier to paddle at touring speeds. The Taran 16 seems to be just as popular as the 18.

The V6 also has an interesting rudder (it's not plagiarism it's a homage :) ). If you can get the rudder further forward it's less likely to come out of the water when surfing a wave.

I know you want to make your own design but maybe you'll get some inspiration or design tips from Bjorn Thomassen's site. I think he uses computer programs to design his boats. A hull shape has to find the right balance between conflicting variables to achieve the design aim.

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Sun Feb 03, 2019 6:00 pm

Cheers.
I haven't much talent with craftsmanship.
Browsing timber sales I know I can obtain cedar strips.
After constant thought (30 hour highway drive time) I might toss the plug idea out of the window and strip construct.. Seems a lot more feasible an idea and a lot less messy and just as strong a result.
I totally agree with shorter boat strengths. Acceleration and maneuverability being two of such. Less wetted area could also be included as per flat water fatigue cruising below the Hull displacement speed.

Thanks regarding the above web site, I love homework, sincerely.
I've had a couple of Guillimot kayak building books a few years. The Petrel would suit our coast. I like the great Auk due to it's a relaxed build.. Nice and easy.
Will be continuing drawing pictures and basically thinking a great Auk bow with some more volume to help run on steep chop. Stretched length ways. Narrowed to allow body shoulders to overhang gunnels partially. Similar to a white water climber the plane shallow into as sharp an aft as strips allow (or maybe not so harse but visually obvious with presence).
Maybe a rudder? Maybe a permanently mounted skeg attached later?
I'd probably prefer a Taran 16 too. Transport.. Blowy days. Less fatigue at my normal pace?
The 15 footer I use glides perfectly, the 13 footer is just as stunning and the reason I am studying how to back pressure the plane and maintain above displacement speeds. I don't know how they trap the displaced water prior to the void. I don't even know if I'm correct. Quite a nice old boat though.
Strip planks seem normal though.. Should reduce the wet area due to the flowing nature of wood..
If it copes well a mould can follow, if not it is my boat and seaworthy.
Thanks heaps guys.. Girls..
I had initially thought that foam+wood into plug into mould into boat would be the easiest way. Glad I asked. Nathan

Water flows.. A miniature gravitational system that likes easy paths.. Controlling such with design will allow controlled masses of force.

Mcgruff, thanks. I like the look of Freq and Panthera. Either would suit me. Nice rockers. I love surfing.
I'm out.. Sitting on build a month or so.. Will know later if my drawing skills are worth much.. All them boats are fast enough.. I love playtime. Shoals here are nice. Beach side. Wind chop shallows running along coast..
Maybe 45 degree long shore drift? And/or. The shipping lane edges the outer shoals and swells during spring. Have consistently surfed a 24 foot sail boat along them.. It pumps from 12 fathoms to about 4 fathoms and runs miles.

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Mon Feb 04, 2019 7:38 am

I want to thank you guys and disappear. Thanks.
Here were some thoughts regarding design. Hope it helps.
Having started on a high performance skiff; a wave ski, use of rocker is extremely important!
But being s skiff and having the power of only 1 man, although an extremely stable platform, touring is useless.
I read a lot about the evolution of semi displacement hull kayaks but I admire the thought of a large volume plumb bow with little primary rocker because.
1. The volume will help prevent over speed bury.
2. The gunnel rocker should work well.
3. Clothing has evolved too hence staying warm while laying on water.

Also found a program, Kayak Foundation? It's written about 5 pages deep on this forum in a topic regarding design.

I do admire pointy nose taunt skin type kayaks that often use 2 or 3 separate rockers of differing radii. That'll surely suit some more than top speed and a rocker all the way over. Eg playful, maneuverability, etc..
Conditions here suit either.. What really matters is seaworthiness!

The ocean has no friends. The ocean has no foes. The ocean is obedient to natures natural law which includes the momentum of a span of many miles.

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Tue Feb 05, 2019 9:33 pm

Thanks to you guys I think it's a much better idea. Instead of a plug; a boat.
Doubting high performance, aiming at suitable to me.

Not needing hatches and knowing how much easier it is to hose off a shell and a cockpit.
Knowing some benefits of wood but non familiar with joining the end; bow, stern.
Looking into computer cut foam. Fore. Aft. Routed at cockpit ends to marry a cedar strip cockpit. Length routed to marry a few full length strips.
If theorical weight total with cloth, paint, resin, foam, wood and rope come in under 20kg then too me that could be a strong buoyant vessel without breaky bits, without bits that rust and with length to achieve a higher cruising speed. If hopeless in real conditions it wouldn't matter too much because the 4metre girl in the shed is much the same; no breaky bits, no hatches, foam ends, etc. She has a gel coat but I'm guessing paint over 3 layer cloth over solid foam with stringers should stay rigid.
Just a paddler too.

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Wed Feb 06, 2019 8:23 am

Totally lost track.

Found this.
Looks easy.
Looks beautiful.
Functional at 14kg give or take.
Project above can be paper while building this.
Shrike. http://cnckayaks.com/shrike/thank-you/

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Thu Feb 07, 2019 5:58 pm

Thanks anyway..
My lies above.
My failure here is seen as my success with more paddle time instead.
Theoretical weights, down time, costs, loss of room space... All added up.
Here's to paddling. 😊

User avatar
nickcrowhurst
Posts: 1099
Joined: Sun Aug 06, 2006 11:07 pm
Location: Cornwall, between swims.
Has thanked: 39 times
Been thanked: 47 times
Contact:

Re: Building a plug

Post by nickcrowhurst » Fri Feb 08, 2019 2:27 pm

Boatsie, have you also considered our strip-built Vember? Both Shrike and Vember can be scaled for length and beam in the paper print-out of the free plans PDFs, but with Vember one can also vary the beam and the length independently of each other: http://cnckayaks.com/vember/
You may have already read this thread: viewtopic.php?f=4&t=110381
Nick, of CNC kayaks

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Fri Feb 08, 2019 6:42 pm

Yes.. Cheers.

What's that saying? Like a bull out of the gate?
I should relax a bit because I haven't a concrete floor yet and I enjoyed reading a build of yours. I doubt I'd be clean enough at the moment..
Beautiful looking boats. Either would suit here.
I just want to build a couple of high quality boats. I have a variety now of different sea conditions and believe much of recycling. 3 are plastic, 2 of the plastics have shape that love it rough but leak a lot. Melt pots already exist that recycle that type. The composite boats are a ski, a 4 metre plumb end that reminds me of a tiny Taran and I was surprised when I saw a picture of a Taran having wanted to build a stretched thinner model of that 4 metre girl and someone had already perfectly accomplished that. 1 more which I use most. All well kept believing that hot pots will technologically improve someday and allow recycling of.
Dad had built a high quality Paper Tiger 14 foot catamaran a quarter century ago. 1 of the first foam sandwich Hull sets made by a bloke down south. The tramp cut at an angle to allow tension on 1 edge. His workplace had trouble with titanium so he bought the left offers and rigged the boat. Below race weight, extremely rigid, water police attempted to book him exceeding 7 knots but he pointed out he only sailed past. The state champion was impressed with the boat and gave dad his number to hold in case the boat became available. He bought it. Still on the race register under the old laws and was raced with lead blocks on the keel lines.
I ain't anywhere near as good a craftsman as dad and you but I'm much considering a very slow build.
I think I'm retarded as a builder. Both eyes have vertical stigmatism (they're not round), hence alignment proper is sometimes difficult (built to clearly define movement). Swaying towards strip cedar on this reason: let the wood brace its lay.
I inherited some machinery and just have to wait to achieve cove and bead technology and a clear clean work space.
Thanks.. I admire your boats, I also admire and have Guillemot Petrel plans which is halve a metre longer but the shoal chop at Semaphore would be awesome with a Vember. If I get my head around and stretch the 4 metre into a strip build plan I'll send you a copy to make as free as you wish.
Kind regards, Nathan

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Fri Feb 08, 2019 8:19 pm

Here's a picture of a 1963 built kayak awaiting gel coat repair. I don't understand the physics but whomever designed this knew what they were doing. The fore to plane is a smoother transition than the plane to aft. Somehow the balance of the displacement wave seems to be a pressurization aft of plane hence the ability to glide as the displacement wave surfs the vessel. I've seen this basic principle used on a 24 foot keel boat where as the water line of the vessel was about 18 feet until crew weight in cockpit lowered her stern. She was much faster than many 30+footers.
I haven't much idea of why with regards to how but someone does and I'd like to build a kayak that is stable and fast hence the skiff and the recycled use of energy with surf. Maybe I'll never figure it out but I haven't much to lose doing the homework.
I almost had 2 engineering degrees but I had a cigarette in the cigarette zone. The security guard walked past the automatic opening doors and asked me to move because smoke was blowing in the door. I pointed out that it would be illegal if I moved to another location to smoke and that if she walked back inside, the door would shut and if her fat arse didn't walk past the sensor, smoke would not enter. The government research facility cancelled my grant and I now love life as a labourer/driver . Enjoying kayaking because when a boat's broken it has somewhere to sit and dry out and spare kayaks are all quick and easy. Onto the roof racks, launched.
Just got the bug to try to design and build something as easy as she. I really hope I'm not offensive.
Just mind blown at the moment. Thanks

Image

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Fri Feb 08, 2019 8:42 pm

I write too much and sleep not enough.
A long skinny Vember would be ideal.
The river flat in Lee of the outer breakwater. Around the heads. Grab some swell and run along the outside.
I'll probably never figure the theories of displacement yet practicals are always fun.
Thanks Nick.
Kind regards, Nathan

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Sat Feb 09, 2019 4:38 am

Probably long in the tooth by now yet dad flipped his cat during over speed and snapped her mast. The hulls and rigidity remained sound and undamaged. The bloke whom built the hulls did an awesome job.
My first job was tendering yatchs men to and from the many moored yatchs. I was allowed to assist repair maintenance and heavy wind situations, etc but I observed many differences between shapes and materials.
Later on I snapped my first kayak. She was repaired with cloth and then learning the same manoeuvre again, I snapped her again at location similar yet next to the repair.
Down here we have some decent size sharks. They aren't monsters, just big. A mates old man and his buddies used to sail out and regularly swim with a local 18 foot great White (I wouldn't do that but some did). Dads mate is another example. They didn't see him coming. Diving on a 70 foot ledge, a 16footers displacement wave bounced them on a reef as he missiled past, took a spear gunned fish from another diver and then as quickly as he had appeared, he vanished.
I like strong waves, I intend a strong build, I'd rather not to heavy. I noticed the Shrike had an epoxy coat, I was unable to think straight regarding a 4mm marine ply sandwich with 200gsm Kevlar/carbon or glass.
A plug would be nice but I think it's easier to buy a professionally built unit because there are many fantastic designs available and often frequent 2nd hand.
Strip cedar seems to me the fairest way to achieve a self built boat. Unlike the bigger sisters, maintenance isn't an issue and with regards to repair if ever needed I'm guessing cut and paste with foam pack.
I much like Vember CNC, I much like Petrel Guillemot and I much like plumb ends.
Any of they will do nicely..
A lovely clean wilderness exists below the surface.
I hope you paddle much too because I don't paddle enough.

Boatsie
Posts: 35
Joined: Fri Feb 01, 2019 7:51 pm
Has thanked: 14 times
Been thanked: 3 times

Re: Building a plug

Post by Boatsie » Sat Feb 09, 2019 6:08 pm

I used Kayak Foundry. The boat design looks similar to the yellow one above except it is longer and narrower.
Still tweaking slightly.
Display reads total resistance at 5knots around 6.13 without stability, 6.88 with loads of stability or somewhere between.
Has keel rocker, large volume bow with lots of gunwale rocker, a bigfoot cockpit and about 1.8 square metres of plane (or 1.2sqm, I can't remember).
I confused myself with displacement theories, I'm no expert, if you want a copy you are welcome to such, just send a private message and I'll upload the file.
A fellow boatsman.

Post Reply