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Thread: Another two sheet rowboat design- "Big Guide"

  1. #36
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    Default Re: Another two sheet rowboat design- "Big Guide"

    I think the sailing version looks very nice, and I am on my third sailing canoe. The first a Solway Dory Curlew, then an Oughtred MacGregor and currently a lovely fully decked Solway Dory Shearwater, seen sailing here on the Solent. This was my first ever sail in her. The outriggers give tons of confidence yet are rarely in the water.

    http://www.youtube.com/watch?v=cy816d_-Fi8

    If you would like to send me the dimensions of the sail I could lay out the sail in Sailcut4 and post the panel dimensions and cutting files to make the sail at home. I would need all four edge lengths, the corner to corner length, the yard angle and the mast angle (or rake).

    I would like to build Big Guide this winter as a two piece hull. Since she is symetrical I would simply build two identical halves. The front edge of the seat could run across the top of the two bulkheads which are bolted together. Could you possibly lift the lines of this centre bulkhead off the plans?

    It would be great to be able to carry the two halves separately down the cliff steps where I live, bolt them together and row away! I think the flat centre plank keel is ideal for shore launching. This feature seems present in all beach launched boats / surf dories. I have read very good accounts of Guideboats in rough waves.

    Perhaps quite domed decks fore and aft, with bulkheads to give really good end buoyancy as well.

    I think she would make a nice sailing canoe. Her beam is close to my current Shearwater's 40", which works much better than the narrow hulls.

    Brian

  2. #37
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    Default Re: Another two sheet rowboat design- "Big Guide"

    I can not tell if these drawings make sense (dimension centimeter). I tried my best with the help of Todd Bradshaw's book "Canoe Rigg".


    Standing lug rig



    Balanced lug rig version





    I'd be interested to see a two part big guide (or any other build as there is no hull #1 so far). I do not think this design has the sea-worthiness of an adirondack guide boat, it is more like a beamy canoe with more flare.

    Center bulkhead:

  3. #38
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    Default Re: Another two sheet rowboat design- "Big Guide"

    The balance lug looks better and will be easier to handle in a rowboat, especially if one uses the sail rig as more of a fair winds sail. All my rigs for rowboats are downwind rigs, but a small leeboard isn't a bad idea. Keep it small and easy to manage and just plan on sailing off the wind. I find a fine hull of a rowboat is much more fun to use as a rowboat upwind and downwind, but when you are tired or have a nice run home, put up the sail. It is hard to build in real stability into a rowboat hull for upwind sailing.

    The balance lug will behave much nicer off the wind than the standing lug, with the self-vanging properties inherent in a balance lug.

    46 SF seems about right.
    Clinton B. Chase
    Portland, Maine

    http://tinyurl.com/myboats

  4. #39
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Thanks flo-mo for posting the bulkhead dimension.

    I have been thinking about the sail size which might be appropriate for using as a sail-assist on a rowboat. There is nothing worse than too large a sail on a hull designed for rowing. Such hulls are so easily driven, that very small sails will drive them easily as fast as a rower might want to sail. 44sq ft is the size the very keen UK open canoe sailors race with. My Shearwater sailing canoe uses outriggers for extra stability. See how easily driven she is and how quick when the wind picks up at 46 seconds in, the sail area of the sail is just 44 sq ft. She is 16' long with a 40" beam and very firm bilges.



    My first sailing canoe had a lug yawl rig. Nice low centre of effort. The mainsail was just 30 sq ft and I think that on it's own would be very pleasant to use on a rowboat hull.



    Solway Dory have a very nice expedition rig at 24 sq ft which drives a canoe faster than one can paddle.



    http://www.solwaydory.co.uk/products...pedition-rig-/

    So I think anything from 24 sq ft up to 40 sq ft could be used. The 30 sq ft main might be just right and does fold up nice and compact. Very small diameter spars and a much easier sail to make.

    I am just sorting out a new computer, so have lost all my previous sail designs. However I have already downloaded Sailcut4 and will lay out some sails this week.

    Brian
    Last edited by keyhavenpotterer; 12-14-2010 at 03:58 AM.

  5. #40
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Some good reading here about designing a plywood version of the Adirondack.

    http://www.guideboat.ca/16ft_guideboat.html#conclude



    I have downloaded Sailcut4 to my new laptop and laid out your 4.3m sail. I just need to relocated the free output to pdf virtual printer I had on my old machine. Then work out how to post a pdf file. Then I can show the 3d sail and the developed panels.

    Brian
    Last edited by keyhavenpotterer; 12-16-2010 at 12:34 PM.

  6. #41
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    Default Re: Another two sheet rowboat design- "Big Guide"

    have now downloaded the pdf creator and uploaded the output to google docks. If everything works, I can show the line drawing of the sail and the individual panels for 4.5m sail and the smaller 3.0m sail.

    This is the sail outline with panels draw in.

    https://docs.google.com/leaf?id=0B4B...M2UzM2Jl&hl=en

    This is the individual panel plots for each panel of the vertically cut 4.5m sail

    https://docs.google.com/leaf?id=0B4B...NGI4Zjgx&hl=en

    And the smaller 3.0m sail. The dimensions are luff 1120mm, boom 1900mm, leach 2480 and yard 1680mm.

    https://docs.google.com/leaf?id=0B4B...NjFjOTc2&hl=en

    Brian
    Last edited by keyhavenpotterer; 12-16-2010 at 02:45 PM.

  7. #42
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Here are the dimensions for a large number of common boat sails.
    http://www.boat-links.com/Sails/index.html

  8. #43
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Thanks, as an example, here's the Opi rig at 36 sq ft laid out using Sailcut4

    https://docs.google.com/viewer?a=v&p...ZjU4NzEx&hl=en

  9. #44
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    Default Re: Another two sheet rowboat design- "Big Guide"

    [QUOTE=keyhavenpotterer;2806721]

    I have been thinking about the sail size which might be appropriate for using as a sail-assist on a rowboat. There is nothing worse than too large a sail on a hull designed for rowing. Such hulls are so easily driven, that very small sails will drive them easily as fast as a rower might want to sail. 44sq ft is the size the very keen UK open canoe sailors race with. My Shearwater sailing canoe uses outriggers for extra stability. See how easily driven she is and how quick when the wind picks up at 46 seconds in, the sail area of the sail is just 44 sq ft. She is 16' long with a 40" beam and very firm bilges.[QUOTE]

    There is also nothing worse than a boat without enough sail area. I found on Drake that the Shellback rig was just right, but because I am going downwind mostly, the hull has great secondary stability, and reefing is easy to do, a little more in my lug on Drake would be OK. I may bump up the area to 50-55 with a nice couple reefs to control the throttle. I am going to cut the sail so it has a deeper draft and provides some power especially on a reach like below at the Small Reach last summer.


    Sailing Downwind SRR 2010 by Clint Chase Boatbuilder, on Flickr

    Big Guide appears to have nice flare in the hull sides, so I suppose you could always add a panel to the sail if you feel like you can get more area. I have found that it is good to make the yard and boom a little long initially. The subject of a boom is always interesting. I have found that the boom is quite nice to have in a solo boat. Keeps hands free for the rudder lines and the sheet. There is plenty to do sailing a narrow boat.


    I can go on and on about rowing and sailing like this....
    Clinton B. Chase
    Portland, Maine

    http://tinyurl.com/myboats

  10. #45
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    Default Re: Another two sheet rowboat design- "Big Guide"

    I neither have the knowledge nor the experience to add something substantial regarding sails and rowboats but I want to thank you all for your efforts and your input.

  11. #46
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Another good and cheap solution would be to find a used Optimist sail and rig. I have sailed these things A LOT.... many years ago. The sails are normally very well cut.


  12. #47
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Quote Originally Posted by Clinton B Chase View Post
    I found on Drake that the Shellback rig was just right, but because I am going downwind mostly, the hull has great secondary stability, and reefing is easy to do, a little more in my lug on Drake would be OK. I may bump up the area to 50-55 with a nice couple reefs to control the throttle.
    Clint, I found sailing off the wind in gusty conditions with that size of sail very unstable in an Oughtred Skerrieskiff. Upwind was ok, I could sit against the force of the rig and she was fine, downwind the gusty wind meant I struggled. In a lull I would have to move in fast to the centre of the boat, then a gust sit further out quickly. She felt very unstable, the hull not capable of carrying my weight as soon as the wind eased. I have had a similar problem with my Ougthred MacGregor. Hence my fear of too much sail area in a narrow hull. Skerrieskiff had 60 sq.ft. which is why I felt a smaller rig would be more comfortable. Hull lines here
    http://www.jordanboats.co.uk/JB/Iain...5%20&%2017.pdf


    Your Drake must be such a nice design to give you this confidence to consider a larger sail.

    Brian
    Last edited by keyhavenpotterer; 12-19-2010 at 12:29 PM.

  13. #48
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Quote Originally Posted by aldebaran View Post
    Another good and cheap solution would be to find a used Optimist sail and rig. I have sailed these things A LOT.... many years ago. The sails are normally very well cut.

    Absolutely, I have a brand new (well unused old) Opi rig just waiting for the right hull to put under her. I understand the problem with Opi rigs though is reefing when you need to.

    Drake is such a pretty boat, and great handling too



    Brian

  14. #49
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Brian
    I good tip on your two piece Big Guide. Build it as a complete boat, with the two 'joining bulkheads' separated by a layer of thin card. When finished, cut it in half with ones Japanese pullsaw. The card is soft, so guides the saw between the bulkheads. I think I saw this idea on a certain website to do with backyard boatbuilding a while back.
    Andrew

  15. #50
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Water Craft featured a 30' gig built below decks on a ship, then cut in half the same way. Will need great confidence. I quite liked the idea of building one half on a jig to keep it straight and true so only a small space is needed, ie an indoor space!
    Brian

  16. #51
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Quote Originally Posted by andrewe View Post
    Brian
    I good tip on your two piece Big Guide. Build it as a complete boat, with the two 'joining bulkheads' separated by a layer of thin card. When finished, cut it in half with ones Japanese pullsaw. The card is soft, so guides the saw between the bulkheads. I think I saw this idea on a certain website to do with backyard boatbuilding a while back.
    Andrew
    Erecting bulkheads in the middle of a canoe hull is not a good idea. Because the ends of the boat are so fine a solo paddler/rower must be able to inhabit the center of the boat to be able to trim the hull to suite wind conditions. And canoes are sensative to where the center of gravity is so any seats must be set at a height that will keep the boat from feeling tender.
    So until someone has built one of these and can say how it handles in various conditions I would say the two-piece hull should be set aside.
    Last edited by Cuyahoga Chuck; 12-19-2010 at 01:47 PM.

  17. #52
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Flo mo , this is one of my all time favourite threads, along with your previous build. We have a 15 ft cedar strip rowboat which I converted to sail last year and 50ft makes it hum along nicely and is manageable in most. 90 ft is pretty full on sailing.( it rigs either with 1 or two sailing dinghy rigs)
    I don't actually agree about the rake in the mast, it might look nice and 'rakish' but the boom always drifts into the centreline in the light, so plumb is correct as far as I'm concerned. Admittedly I'm more of a keel boat sailer where all the gear is heavier and that can become a real issue and problem but nevertheless....
    I love those two boats of yours .. have a great christmas.
    Last edited by John B; 12-19-2010 at 03:38 PM.

  18. #53
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    Default Re: Another two sheet rowboat design- "Big Guide"

    I think the one piece build is to keep the lines fair before cutting. But being in a warm space looks attractive over there right now.... Funnily enough it is +9c min. here and similar for the next few days. Can't last..
    A

    Oh, and a bulkhead doesn't have to be full. More of a stiff frame, so the seat can be low.

  19. #54
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    Default Re: Another two sheet rowboat design- "Big Guide"

    John B, I agree about the mast.

    Andrew, yes the bulkhead would not be full height as you point out. Looking at rowboats, the seat height might be say 8", with oarlocks about 5 inches higher still. So the max height of the twin centre bulkhead would be be say 7", in which case it will support the seat and help form a stiff assembly, but also be deep enough to be well above the outside waterlevel. That's what I have in mind.
    Just checked back on the mid-centre bulkhead measurements. The gunnel height is 13" above the floor, so that's just right for our 8" seat height and 5" seat to oarlock height. Again, checking the layout drawing above, the seat is fitted 7" above the floor, so it's nice that the rowboat drawings I have place the thwart/gunnel relationship in just the same place as Big Guide's.

    Brian
    Last edited by keyhavenpotterer; 12-19-2010 at 04:10 PM.

  20. #55
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Flo-Mo,

    I love this design, particularly how the panels are laid out on the 4x8 sheets (I know you drew it metric, but...). I have a fair amount of left-over 6mm meranti (it might be a bit stiff for the twist in the middle strake) from my Valgerda build http://ricksboatshop.blogspot.com and would like to put it to good use.

    A couple of questions:

    1.) It appears that the offsets from panel edge to panel edge leave no room for a kerf. Is there room for the 3mm one will lose for each rip? In my case, it's moot as I will be getting the parts out of off-cut pieces, but for those considering this build with virgin sheet goods it becomes a consideration.

    Since you have only built a model (so far) it is probably difficult to answer this.

    I will loft your offsets onto a sheet of 3mm doorskin and cut the panels individually to use as patterns. I'll let you know what comes of the process.

    2.) The lines plan shows considerable back rake on both stems. It's a striking and beautiful design element, one that is key to guide boats. This feature is not apparent in the models you built. Is this something that needs to be "tweaked" during the build, or is it just a function of the angles the model was photographed? You posted the grid showing the curve of the middle strake. The back rake isn't apparent there, either.

    I've got quite a bit on my plate for projects, but building this boat looks like it will be time well spent.

    Thanks for posting the drawings, offsets, and photos.

    I'll update as I move forward.

    Rick
    Last edited by Rick Nardone; 12-23-2010 at 03:58 PM. Reason: typo

  21. #56
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    Default Re: Another two sheet rowboat design- "Big Guide"

    If you start with a virgin sheet, I would recomend to cut the panels with a japanese pullsaw. The pencil line and the kerf should have in at the same width, so I would cut exactly along the pencil line. I would take my time because each cut produces the edge of two panels and each mistake will effect both panels.

    The rake of the stems is there but actually gets lost in the pictures taken from above.

    Nice to hear that you like the design and maybe there is a chance that you will build one. If you have any further questions I will try my best to answer them.

    Happy Holidays Everyone!

    Stefan
    Last edited by flo-mo; 12-23-2010 at 06:50 PM.

  22. #57
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    Default

    Has anyone ever built one of you big guide boats?

  23. #58
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Flo-mo,

    You are amazing. Keep up the good work. The only down side for me is I'm sitting here wondering what you could do with three sheets.

  24. #59
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    Default Re: Another two sheet rowboat design- "Big Guide"

    Quote Originally Posted by keyhavenpotterer View Post
    Clint, I found sailing off the wind in gusty conditions with that size of sail very unstable in an Oughtred Skerrieskiff. Upwind was ok, I could sit against the force of the rig and she was fine, downwind the gusty wind meant I struggled. In a lull I would have to move in fast to the centre of the boat, then a gust sit further out quickly. She felt very unstable, the hull not capable of carrying my weight as soon as the wind eased. I have had a similar problem with my Ougthred MacGregor. Hence my fear of too much sail area in a narrow hull. Skerrieskiff had 60 sq.ft. which is why I felt a smaller rig would be more comfortable. Hull lines here
    http://www.jordanboats.co.uk/JB/Iain...5%20&%2017.pdf


    Your Drake must be such a nice design to give you this confidence to consider a larger sail.

    Brian
    Brian, thanks for the comments. The new rig is 60SF with two reef points. If there is more than 12kts...I will likely have one reef tied in. The other thing is that when off the wind, as you very well know, you can ease the sheets quite a bit to dump wind. BUT, I like to have had a reef tied in by this point. We can also keep the sail nice and flat. We will see this summer when I have the new rig working whether 60 is too much. Also remember, I am 205lbs and 6'6"...that helps!
    Clinton B. Chase
    Portland, Maine

    http://tinyurl.com/myboats

  25. #60
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    Default Re: Another two sheet rowboat design- "Big Guide"

    A boat of similar dimensions, with a 57 ft sq balanced lug main by Todd Bradshaw. The mizzen is an additional 10 ft sq.http://

  26. #61
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    Default Re: Another two sheet rowboat design- "Big Guide"

    I built this design and wanted to report that the offsets are good. I built it with 1/4" ACX underlayment ply from Menards.

    Big Guide Measurements


    Hull is taped but no gunwhales, frames, seats or finishing


    186.5" Length, upper stem to upper stern


    40" Relaxed Amidships Beam


    42+" Stretched Amidships Beam


    14" Amidships Height


    2.5" Rocker


    19.5" Stem Top to Stem Bottom (and Stern)

    https://imgur.com/a/Mld2bWP

  27. #62
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    Default Re: Another two sheet rowboat design- "Big Guide"

    That is a lot of boat to get out of two sheets. How are you going to finish it out? Sail rig? I'd be really interested to know what the final cost is, ready to go.
    -Dave

  28. #63
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    Default Re: Another two sheet rowboat design- "Big Guide"

    I'm going to build flotation fore and aft, and see where it goes from there. I have all winter to work on it.

    To get it to rowable condition, 2 sheets of ply, 50 yards of 6 oz 3" wide glass tape, about 3 yards of 4" biaxial tape, a gallon of epoxy resin plus hardener, some fillers, stir sticks, paint brushes, mixing pots, paint and oarlocks. A piece of 1/2" ply with a stiffener for a seat, some 1x2 fir for outer gunwhales and simple framing under the seat. I am using up a lot of leftovers so I am not counting cost, but its about 300 to 400. Now that I know the offsets are good, I would recommend lighter marine ply. Lighter ply would probably need more framing. The 1/4" ply is pretty stiff, it may be enough with outer gunwhales and one frame in the middle under the seat.
    Last edited by skyl4rk; 10-22-2020 at 02:54 PM.

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