Building 18' dinghy, skiff, panga

Discussion in 'Boatbuilding' started by retrosub, May 15, 2011.

  1. retrosub
    Joined: Aug 2006
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    Location: Ithaca, NY

    retrosub Junior Member

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  2. retrosub
    Joined: Aug 2006
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    retrosub Junior Member

    I put 1" of hard insulation under the bow deck to make a built-in cooler. Cutting the compound angles and fiberglassing it all in was a lot of work. Foam-filled anchor well with a drain that exits just under the spray rail.
     

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  3. retrosub
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    retrosub Junior Member

    The motorwell has skinny compartments on either side. Port side will have a gas tank built in, starboard is a small compartment for lines and such. I foamed underneath and put a drain in it.
     

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  4. retrosub
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    retrosub Junior Member

    Here's a shot of the midseat, it'll be water tight and have a lot of volume. I think the hatch will open sideways. You can see the limber hole beneath.
     

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  5. retrosub
    Joined: Aug 2006
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    retrosub Junior Member

    I bought the plans on impulse just to see if they were any good. I have to say I was really impressed, especially considering how cartoon-ish the website drawings are. The plans include a couple dozen PDF files with lines drawings, every part labeled, jig dimensions, etc., and a 3D model you can spin and examine from any axis. I have plans from Mertens (OD18, FS17, FS14) and Michalak (Bob's Boat, Dorado, Family Skiff) and the DK18 plans are more detailed.

    It looks like there's a lot of rocker in the hull, but there isn't, it's a trick of all that bottom length. I'm thinking about a Tohatsu 20hp 4-stroke so I can take it to Lake Tahoe (no 2-strokes), but I have a line on a 25hp Merc Sea Pro for half the price. I have a little 8hp Johnson for my kaboat, and I'll try that first just to see what it'll do.

    The designer says it'll weigh a bit over 180lbs, another builder measured his at 220lbs. I'm overbuilding the hell out of mine with 12oz biax inside and out, built-in cooler, 3" side decks, etc. I'll be lucky to come in under 300lbs.
     
    Last edited: May 21, 2011
  6. retrosub
    Joined: Aug 2006
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    retrosub Junior Member

    Finished fiberglassing the inside, just a bit of fairing to do. It feels like a major milestone. So far I've used 6 gallons of epoxy, which is twice what the designer calls for. It wasn't a case of making huge fillets or wasting epoxy; biax glass takes a lot of filler, the keel and rubrails are laminated instead of using solid timber, etc. Even being frugal and using a lot of filler, it just adds up to a lot of epoxy.

    It's a tiller-steer boat, so there's no console as such, but I need a place to put the fish finder, GPS, compass, and radio. I'm thinking on the starboard side just aft of the midseat. A little box there could hold all that, run the wires under the stern seat to a battery?

    I've been thinking about how to implement a speargun rack. I'm thinking horizontally under the port gunwale, like rod holders, but larger. We use long guns here for white seabass and yellowtail, so I'll have to cut into the stern seat. Enh, it's too hard to explain, I'm just going to do it and post pictures when I'm done.

    My wife is gone for the weekend, and I have nothing but the boat to keep me occupied. Good times, good times.
     
  7. retrosub
    Joined: Aug 2006
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    retrosub Junior Member

    Side decks are glued on, I need to taper them at the aft end and glue the inwales. Seats are in just for show, there's a lot to do yet before I fasten them down. Mini console (really it's just a shelf) extends from the midseat, I'll mount the GPS and fish finder there, one in front of the other, VHF below. Anchor well cover has a big round hole, sized to fit a 5-gallon bucket. Aside from the ceiling of the insulated fish box, I'm all done fiberglassing.

    Speargun rack goes on the port side and protrudes under the stern seat. I'll take another shot from a different angle this weekend that shows it better. I want to make sure the speargun rack holds all different shapes of spearguns, so I'm fitting and testing a bunch. That's a Sea Sniper gun, my buddy Chris makes the Ferrari of spearguns.

    Can't decide if I should put a limber hole on the port side as well. I only have one drain plug and it's on the starboard side, but I'm a sucker for symmetry.

    Really appreciating all the feedback I'm getting on this build.
     

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  8. Lurvio
    Joined: Jul 2009
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    Lurvio Mad scientist

    I think it means you're on the right track, usually there is all sorts of rockus if someone succests something not too sane. :)

    Make sure the electric gismos can not be kicked too easily as moving around in a boat this size isn't always all that controlled.

    It'll make a fine looking boat. Any colours chosen yet?

    Lurvio
     
  9. retrosub
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    retrosub Junior Member

    Colors: saphire blue below the spray rail white above. Mostly white inside, but maybe the seat tops will show the wood and definitely a mahogany inwale. I'm putting tan SeaDek on the floor, I think that'll go nicely with the wood accents.
     

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  10. retrosub
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    retrosub Junior Member

  11. liki
    Joined: Nov 2008
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    liki Senior Member

    There certainly is interest atleast from here although I have not posted a reply yet. Especially I am interested on what kind of performance you will eventually reach with the finished boat eventually.
     
  12. Nurb
    Joined: Jan 2011
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    Location: IL

    Nurb Junior Member

    Also interested in this boat. When do you get to sea trial her? :)

    I'd prefer the 25 to the 20 at 300 lbs and 18' I think.
     
  13. retrosub
    Joined: Aug 2006
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    retrosub Junior Member

    It's been two months of mornings, nights, and weekends. Sea trials tomorrow.

    I got a brand new 2003 Honda 30 hp for just $300 more than a 20 hp, complete with factory 5-year warranty. The engine seems a bit large/heavy, but the 20 hp was probably too small. I raised the transom from the designer's plan so I could use a 20" shaft motor.

    Electrics are all wired in: VHF, 8' antenna, 200w iPhone stereo, FM radio, removable nav lights, LED rope lights under gunwale, two 12v accessory sockets, fish finder, GPS, compass.
     

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  14. troy2000
    Joined: Nov 2009
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    troy2000 Senior Member

    I missed this thread somehow, until you bumped it. I'm surprised there was such little response; it seems to have slipped under the radar with a lot of other folks here too. Puzzling....

    Looks like a fun project, and a nice boat. Please update us on the sea trials when you have a chance.
     

  15. retrosub
    Joined: Aug 2006
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    Location: Ithaca, NY

    retrosub Junior Member

    First time on the water was a success, no leaks or creaks, it feels solid and handles predictably. It's very stable for such a narrow boat, both at rest and in motion.

    The RPM/Hour meter is still on order, so I'm not sure how many RPM I'm running yet, but I'm a little surprised that I only saw 20 mph. Still breaking in the motor so I didn't open it up all the way for more than 20 seconds. The engine feels like it's taking a lot of power to go that fast, whereas it's very happy to run at 15 mph or less.

    There is some rocker in the hull and I think that may be keeping the top speed down. With the motor in the middle trim position it really wants to stick the bow up in the air, so I trimmed the motor down all the way and it runs better that way. But I'm at the last pin, next time I might try removing the pin and see if it runs better all the way down.

    I wonder if a hydrofoil on the motor or wedges on the bottom would help? I'm not that concerned with speed, I mostly want economical cruising speed and I'm happy with 15 mph, so perhaps there's nothing to fix.
     

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