Page 6 of 37 FirstFirst 123456789101116 ... LastLast
Results 76 to 90 of 551

Thread: Tom Cat

  1. #76
    Join Date
    Dec 2007
    Location
    Guernsey Channel Islands UK
    Age
    54
    Posts
    307

    Default

    Quote Originally Posted by PAR View Post
    A good rule of thumb with joints is to always permit an natural way for water to escape a joint, if it gets in. With scarfs, they'll slope away from water flow, as to prevent water being forced up into them underway or because of natural water paths. In deadwood assemblies you'll see this a lot, having the scarfs face aft ( ). If you have no other choice but a forward facing scarf, then a s
    "stopwater" is installed to tighten the joint if water does manage to get up into it. Stopwaters are traditionally employed along the rabbit in keel and deadwood assemblies to prevent water from getting past the caulk line, but are also used to tighten joints when necessary.

    On a notched scarf like that one, I'd install the stopwater right at the point of the lower notch, which will also serve to relieve any stress risers at this location.

    Note how water can't "climb" up into the joint in this orientation, but it might if this was reversed to the water flow. The stopwater is located as suggested, at the lower notch point.

    The work thus far looks great . . .
    thanks for the great explanation PAR i hadn't thought about the water ingress in the joint facing that way, i though they were done that way so if the joint did open it wouldn't catch on any thing

  2. # ADS
    Google Adsense Advertisement
    Join Date
    Always
    Location
    Advertising world
    Age
    2010
    Posts
    Many





     
  3. #77
    Join Date
    Feb 2008
    Location
    Eustis, FL, USA
    Posts
    2,270

    Default

    Water in an insidious beast and can get into things we'd hoped, wished, attempted to prevent and cursed that it wouldn't.

    The old timers knew and simply accepted this as the nature of things and planned their joints around the eventuality. I rebuilt the deadwood assembly to a Concordia yawl a number of years ago. Each joint was planned to have water invade it and most used this to advantage, making the joint tighter. One of the more complex deadwood assemblies I've ever seen, but very effective.

  4. #78
    Join Date
    Dec 2007
    Location
    Toowoomba
    Age
    72
    Posts
    373

    Default Outer Stem Scarf Joint

    Hi PAR
    Thanks for the comments. However, I'm following the plans to the letter. See Construction plan below. Also don't be fooled by what you see...the scarf joint has not been trimmed to size at this time, just roughly cut. If you see the finished Inner Stem pics in a much earlier mail they clearly show the vertical join flowing in the same direction as the waterflow albeit they are internal. The Outer Stem follows this exact same method of scarfing. The other join is horizontal on both the Inner and Outer Stem so I don't quite see the issue but entirely understand your point. Everything is flowing in the right direction.
    Additionally I think having the Mast Step on a solid foundation with no joins may also be a factor. The whole arrangement appears to make eminent sense to me. I imagine Bill would be aghast if he thought he got it wrong!

    7 Construct Plan.jpg

  5. #79
    Join Date
    Dec 2007
    Location
    Toowoomba
    Age
    72
    Posts
    373

    Default Laminating the Hull

    I couldn’t put it off any longer…had to step up and get it done. With a weeks leave up my sleeve with nought to do I took the plunge, took the heater over to the shed and set to.

    So, first things first. I am using 435gsm Double Bias glass cloth (or Biaxial whatever your bent with naming). Before I hear mutterings of “overkill”, “too heavy” etc I would like to explain why. First, the designer has mentioned the use of Biaxial cloth in his writings on the construction of a strip built Tom Cat stripped with WRC. Secondly, 435gsm was recommended by the vendor after explaining the construction method and the fact that I was using Paulownia for the strips. Garden also goes on to say that the number of frames can be almost halved by the use of DB inside and out. I was thinking to not have any when I was purchasing the cloth so the 435gsm made sense to me. However, on reflection I will still put some frames in because the more I read about the stresses on a catboat the more I think the stiffness will be appreciated. When it’s all said and done, the weight will be about 12KG or less after glassing inside and out.

    The width of the cloth magically covered keel to sheer so was able to drape it on longitudinally in one piece with just the one join running down the keel. I used the dry method as I was working on my own and didn’t want to attempt pushing the cloth around over a wet epoxy hull. As can be seen in the pics it is only held in place with a bit of masking tape.

    I had purchased peel ply with visions of using it to reduce time and epoxy but chickened out as I had no experience with he stuff at all and was on my own, maybe on the inside. Need to use it somewhere to get a feel for it first.

    My layup went like this...
    · Batch sizes were 300gm. I had the wonderful good fortune that my better half was no longer in need of her kitchen scales. The old type with weights and there was a 200gm and 100gm weight that just suited the Bote Cote 2:1 resin/hardener ratio perfectly (great stuff, easy to use). Even had a Tare adjustment for the different sized containers I was using. Now I have a permanent set of scales in the shed so I’m a very happy chappie! My containers are the bottoms of 1 Litre plastic milk bottles or the bottoms of 400 tablet containers of Fish Oil capsules. (Love both of these for epoxy work).
    · I worked out I’d need at least 5 batches to get the job done so I readied 5 containers with 200gm of resin and set them aside so that the hardener would be all that was required. I used Slow hardener for the first two coats followed by Standard hardener for the rest (chicken again!). Same both sides.
    · Starting in the centre, pour on the epoxy and using a squeegee get it spread out over about a 700smm area ASAP. When it came to the topsides I rolled it on using a foam roller. The vertical surfaces were harder to do as getting enough epoxy on to saturate the glass was more difficult. However, it wasn’t an issue using this method, just needed to be careful and take more time.
    · Once the batch was on and the glass was transparent, I used a fibreglass roller to ensure good glass/hull contact.
    · I then used the squeegee to pull thru the excess epoxy keel to sheer or onto dry areas (they’re usually white and stick out like the proverbial) or onto a new area so ensuring no excess epoxy was going to float the glass.
    · Continue the batches until this first important coat was complete. This first coat took just under 6 batches.
    · Wait until the epoxy kicks and becomes tacky then continue with another straight batch wet on wet using a foam roller. It only took 2 batches for this coat and subsequent coats.
    · When this one kicked, the new batch included sanding filler at a ratio of about 1:0.8 (epoxy mix : filler powder). I think it worked out something like this…24 pumps resin, 12 pumps hardener (= to 300gms approx) and 6 coffee measures of filler. I’ve never measured my coffee measures so not sure. I just mix until I think the consistency is in the manageable range I’m after ie. in this rollable.
    · Two coats of the above.
    · Last coat as above but with some tint added. (One side was completed in one day).
    · The important thing was to trim the glass when the first coat had kicked and was still green.
    You will note in one or two of the pics I took near the transom that I used aluminium foil to protect it and also I have used a cabinet scraper for a bit to ascertain the thickness of the layup after it had gone off. I wanted to know if I’d done enough coats to be able to begin the final fairing process before paint. I think so.

    All that needs to be done now is wait for the epoxy to go off properly (about a week) before I continue with the scraper, torture boards etc.

    STARBOARD SIDE after saturation

    DSC01409 (Medium).JPG DSC01408 (Medium).JPG DSC01406 (Medium).JPG DSC01403 (Medium).JPG
    DSC01402 (Medium).JPG DSC01400 (Medium).JPG

    PORT SIDE prior to saturation

    DSC01415 (Medium).JPG DSC01414 (Medium).JPG DSC01413 (Medium).JPG DSC01410 (Medium).JPG
    Last edited by Dry Water; 11th August 2009 at 05:06 PM. Reason: Catspaw amended to Tom Cat

  6. #80
    Join Date
    Mar 2007
    Location
    Adelaide
    Posts
    2,139

    Default

    Thanks for all the build ideas/tips, she is looking good.

    It's strange how some tasks do require a bit more drive to get done while others you just walk into the shop and get stuck in.

    Why aluminium foil and what type?

    Cheers
    Mike

  7. #81
    Join Date
    Dec 2007
    Location
    Toowoomba
    Age
    72
    Posts
    373

    Default

    Quote Originally Posted by m2c1Iw View Post
    Thanks for all the build ideas/tips, she is looking good.

    It's strange how some tasks do require a bit more drive to get done while others you just walk into the shop and get stuck in.

    Why aluminium foil and what type?

    Cheers
    Mike
    Hi Mike... it's a pleasure doing the thread. I get to keep a record of the build in photos and dialogue etc I have heaps more photos but could not in all honesty provide them all.
    The al foil is just straight kitchen stuff from Coles. Like anything it was just a tip I read somewhere. Better than paper for keeping runny pox off the boat. Worked a treat as well. The masking tape was a bit of a worry as well but I took it off immediately the epoxy had kicked on the last coat.
    Thanks for taking some interest.
    Cheers
    Laurie

  8. #82
    Join Date
    Dec 2007
    Location
    Toowoomba
    Age
    72
    Posts
    373

    Default Fairing the Hull

    It’s taken some time between work, yard work, holidays etc but tonight I finally finished the first sanding phase ie. get rid of the weave pattern that you can see on my previous pics. When I look back on it I missed an opportunity when filling the weave to tip off the epoxy with each coat. I was just interested in getting the stuff on using spatula and roller and the vertical bits were a bit starved anyway. However, I did get it done in one area and the sanding went much quicker. However, not to worry, sanding’s great for exercise! NOT!!...

    I’m now at the point where I need to add a thickened coat all over to cover some areas where the cloth is close to the surface if not breeching it in some places. I’m not that concerned for a couple of reasons. One being that what has come thru is not the fibreglass cloth itself but rather the stitching that holds the biax layers together. Second, the aim is to get a nice fair hull and to do this I have purchased some black epoxy pigment to mix in with the fairing filler. My aim is to use the long boards only after the coat is on and I anticipate that all the low spots will be immediately obvious. These I will fill and then, hopefully, complete the last long boarding operation to an acceptable finish prior to a final thin coat of straight epoxy. A quick sand and on to paint. I think it’s a plan!

    DSC01427 (Medium).JPG DSC01417 (Medium).JPG DSC01423 (Medium).JPG DSC01424 (Medium).JPG

    Some may suck back at the thought of black epoxy but the colour scheme is grey bottom and black topsides so it shouldn’t be an issue. She will be dry sailed and always under cover when not in use. My existing boat has the same paint scheme and I’ve never had an issue with it. Besides I have all this paint left over from the last build! Talk about over estimating, I’ve enough for another after this one!
    Anyway we’ll see how it goes.

    The pics are nothing special. One shows the long boards I’m using and one more of a feel good thing for me to show the last half square metre of sanding that is now over! And a couple showing the general view. Somebody once commented about how much dust is generated…my analogy is something akin to an explosive blast inside a flour mill! The bloody stuff is everywhere!

    P9290015 (Medium).JPG DSC01428 (Medium).JPG P9290016 (Medium).JPG DSC01429 (Medium).JPG

    Nearly forgot…heaven forbid that I should. My other half has provided the name for the boat…MEERKAT…in deference to the fact it’s a Catboat and that it’s a small catboat and that the word comes from the Afrikaans language which is derived from the Dutch word meercatte, meaning “sea cat” or “lake cat” and the fact that we will sail the boat predominately on the Wivenhoe dam and it’s bloody perfect! She’s a bloody genius!

  9. #83
    Join Date
    Dec 2007
    Location
    Guernsey Channel Islands UK
    Age
    54
    Posts
    307

    Default

    love the name and very appropriate (my other half has just asked are you going to paint a meerkat on the bow )

    as for the sawdust its incredible how much you produce the worst thing about the dust is you've paid for it as well

  10. #84
    Join Date
    Dec 2007
    Location
    Toowoomba
    Age
    72
    Posts
    373

    Default The Bargeboard

    After all that sanding I thought it would be pleasant to do something different that didn’t involve wearing a dust mask and having a screaming, dust creating mass of metal growing out of my hands.

    Aahhh!! The peacefulness of it all. Real wood, pencils, rulers, squares, templates, block planes, spokeshaves, peace and quiet. This is what boat building is all about! (always the ABC radio in the background, just for company).

    The plans call for a bargeboard to cover the edge of the planking and the glass that has been laid down over it at the transom. To commence I have traced the outline of the transom edge onto some 3mm MDF and the used my trusty length of plexiglass and nails and created my oversize template. The width starts at 50mm and narrows to 44mm at the sheer. I cheated here and made it parallel for a distance from the centre and also parallel from the sheer and let the plexiglass weave its magic in the middle round the curve.

    The timber is 25 x 150 hoop pine so I was able to get the majority of the length for one side from it after tracing the outline onto the board. My first attempt at resawing my board in half to get pieces approx 11mm in thickness was a dismal failure. Ended up throwing out my first attempt. However, back to the drawing board and this time used my template and traced the pieces onto the stock first, bandsawed them out THEN resaw. Perfect. So much easier with the smaller bits. Lesson learnt there.

    Onto the thicknesser to bring the bits to thickness, redraw from the template then onto the bench to bring the inside edge down to correct size before fitting to the boat. My strategy was to complete the inside edge, drill and fit the pieces, bring the outside down to size then complete the drilling operation. So far, so good. I have completed the locations and fixings for the inside edge. The idea is to locate the outside edge holes halfway between the inside ones after bringing the outside edge flush with the bottom.

    My only sticking point was the question over the planned bargeboard. The designer had drawn a complete bargeboard over the entire transom perimeter. However, as I want to permanently fix the thing so that I can finish the bottom, the bargeboard needs to be totally complete and I don’t really feel comfortable with completing the deck part. After looking through the Garden book I noted that the plans are different to Garden’s actual build where he has not added the top of the transom portion of the board. Good enough for me so after some heavy consideration I have decided to follow the pics in his book and not the plans.

    I have ended up with two pieces each side so my fitting skills will be put to the test once more. That will be next time. Pics tell the story so far. Happy building!

    DSC01430 (Medium) (2).JPG DSC01431 (Medium).JPG DSC01432 (Medium).JPG DSC01435 (Medium).JPG DSC01436 (Medium) (2).JPG DSC01437 (Medium).JPG

  11. #85
    Join Date
    Mar 2007
    Location
    Adelaide
    Posts
    2,139

    Default

    Laurie,
    Just been reading about Catspaw in WB #176 she is a sweet little boat. Interesting the carvel planked with epoxied seam method of construction on the original, makes you wonder how she has stood the test of time.

    When I read your post about the barge board I must say I wondered about the fiddly detail but having now seen the pics it certainly adds to the finish.

    When will you flip her must be soon now.

    Cheers
    Mike

  12. #86
    Join Date
    Dec 2007
    Location
    Toowoomba
    Age
    72
    Posts
    373

    Default

    Quote Originally Posted by m2c1Iw View Post
    When will you flip her must be soon now.
    Hi Mike
    Much to do before turning.......outer stem needs shaping before fixing, deadwood, keel to be attached after centreboard slot is completed. Two more coats of epoxy all over, paint and then maybe. I'm anxious too! but have plenty of time so steady as she goes.
    Cheers
    Laurie

  13. #87
    Join Date
    Sep 2009
    Location
    Brisbane
    Posts
    5

    Default bargeboard

    |It seems that some building termanology has crept into the boatbuilding scene.
    You are not installing a bargeboard on the transom of your boat, you are installing a transom Covering board.
    The purpose of this covering board is to cover the endgrain of the hull planking.
    Traditionally the transom was planked first and then the hull was planked The end grain of the hull planking ( more suceptible to water ingress ) was covered by the transom covering board so the caulking would seal it from the water.
    Sorry for being so pedantic, but designers know diddly squat when it comes to building boats
    |You appear to be doing a very good job, keep up the good work.
    I have 38 years of expertise in this field, so if you have any problems just P M me Cheers Grump.
    Last edited by grump; 6th November 2009 at 06:04 PM. Reason: bloody spelling mistakes

  14. #88
    Join Date
    Dec 2007
    Location
    Toowoomba
    Age
    72
    Posts
    373

    Default Transom Covering Board

    Quote Originally Posted by grump View Post
    You are not installing a bargeboard on the transom of your boat, you are installing a transom Covering board.
    Grump,,,many thanks for your note. I defer to your years of experience. By way of explanation I have been using the description William Garden has used in the plans. I shall commence to use the correct terminology hence forth (and don't worry everyone else, I did check and he's 100% correct!)

  15. #89
    Join Date
    Oct 2008
    Location
    Victoria
    Age
    71
    Posts
    631

    Default

    I'm looking forward to the turning. Such a lovely hull, and you're doing it so beautifully. I often look through the little book he wrote about the making of the original Tom Cat. If only every beautiful boat could come with such a story!
    What caused the Pacific War? A book to read: here

    http://middlething.blogspot.com/

  16. #90
    Join Date
    Dec 2007
    Location
    Toowoomba
    Age
    72
    Posts
    373

    Default External Backbone

    So the Transom Covering Board (TCB) has been dry fitted and any fairing work around it complete. It appears I am attempting to build a battleship with the amount of fixings involved. I’d have to admit it was an error but no harm done except more screws, more plugs and more weight! I had rounded over the transom to accept the biax glass cloth so there was a bit of filling and fairing involved to fix this area. To complete this I taped the inner surfaces of the TCB with packaging tape and installed it dry onto the Transom. This provided a neat and easy area to fill and fair off.

    DSC01449 (Medium).JPG DSC01450 (Medium).JPG DSC01453 (Medium).JPG

    Before I complete this area I have decided to move onto all the bits for the Stem, Keel etc as they all need some preparation in one way or another in the same manner as the Bargeboard so I have set to for the epoxy encapsulation of all the external Keel pieces including the Deadwood and TCB.

    However, before starting the first task is to fit the Stem to the forward Keel piece (something that I have continually put off because it was going to be a pig of a job to get everything matching up). The issue was the drawing was not clear how this went all together and not having done this before had taken too much off the forefoot during the process of flatting off for the fitment of Stem and Fwd Keel. There was supposed to be a step in the forefoot there somewhere that never got done due to my ignorance of how the joint was to be fabricated. I’ve been umming and aaring about what to do for weeks.

    In the end I inserted a type of graving piece where the Stem was supposed to meet the Keel, epoxied this in place, dressed it off and used it as a backing piece for the epoxy/wood flour mix used to fill the void between the top of the Keel and the flatted off portion of the Hull. Hopefully you can see this in the pics. It all seemed easy in the end and am now wondering what I was fussing about. All I did was tape off the Stem and Forward Keel piece, mix up a very thick batch of epoxy/wood flour, spread that on the area that needed filling and placed the Keel on top. After scraping off the excess, let it set and Bob’s your uncle! It filled the void perfectly. Now with a SB bolt thru the forward end and SB screws elsewhere she should be shipshape.

    DSC01438 (Medium).JPG DSC01445 (Medium).JPG
    DSC01439 (Medium).JPG DSC01441 (Medium).JPG DSC01442 (Medium).JPG DSC01443 (Medium).JPG DSC01444 (Medium).JPG

    I have already given the Deadwood, Aft Keel and Centreboard Keel pieces two coats of straight epoxy but before continuing will shape the Stem so that I can include it, the TCB and the forward Keel pieces in the whole epoxy process. It’s more economical to do this job all at once, wet on wet. I have decided to not bother with glassing any of these. It’s all Tas Oak (except the Deadwood) and tough as all get out.

    Also need to think about the inner face of the Centreboard Keel pieces as they are available to take to finish stage prior to permanently attaching them along with the rest of the external Backbone.
    So still a bit to do before I assemble all the bits onto the hull. Then more epoxy coats of the whole thing and some paint before turning her over.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •