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Hybrid Cirrus LT- Stitch & Glue hull with wood strip deck
(plywood, hard chine hull)

Technical specs...


 Classic, hard chine 'Greenland style' touring kayak for smaller to medium paddlers - featuring a wood strip deck.


Side view Cirrus LT Hybrid


Top view Cirrus LT Hybrid

        Plywood deckCirrus LT frontsStrip deck


Cirrus LT description | MATERIALS | S&G KITS

Cirrus LT All plywood version of this kayak model
Cirrus HybridLarger (original) displacement version of this kayak model
Cirrus SLT Smallest plywood version of this kayak model


Cirrus LT Hybrid plans are completely different than the all-plywood CirrusLT and DO NOT contain plywood deck plates - the deck is STRIP only. The CirrusLT is ALL plywood.
The photos below show example of the Hybrid stations setup from the Builders' Pages.


The "spine" below is just a 3" wide strip of particleboard.
  • Assemble the hull
  • Inserts spine with BOW and STERN stations
  • Add on all DECK stations, staple, hot glue. Ready for strips.
  • For illustration of building principles only.

Building Material

Technical specs are identical to S&G Cirrus with the exception of the wood strip deck.
PropertyEnglishUnitsMetricUnitsComments
Length Overall 16 ft 4,87mlength from bow to stern as designed
Beam Overall 21.5 in 54,6cmwidest part of kayak
Draft 3.864 in 9,81cmbaseline to Designed Water Line (DWL)
Volumetric Properties
Displacement 198.8 lb 90,36kgat DWL
Volume 3.1 ft^3 87,9litersdisplacement in cubic feet and liters of sea water
Wetted Surface 18.06 ft^2 1,67m^2underwater surface area to DWL
LCB 7.75 ft 2,36mlongitudinal center of buoyancy from x=0
LCB % LWL53.23%53,23%LCB as a percetage of waterline length from x=0
VCB2.426 in 6,16cmvertical center of buoyancy from baseline
Waterplane Properties
Waterplane area 14.617 ft^2 1,358m^2at DWL
LCF 7.55 ft 2,3mlongitudinal center of flotation from x=0
LCF % LWL51.9%51,9%LCF as a percetage of waterline length from x=0
LWL 14.558 ft 4,437mlength of waterline; same as DWL
BWL 19.18 in 48,73cmbeam of waterline
Sinkage 77.96 lb/in 13,95kg/cmpounds displaced per one inch of sinkage
Form Coefficients (no units, same for metric)
Cb 0.414    block
Cm 0.783   midship
Cp 0.529   prismatic
Cwp 0.628    waterplane
Area/Displacement8.483   Area / Displacement ratio [ft^2/(ft^3)^2/3]
Length / Beam9.104   Length / Beam ratio [LWL / BWL]
Miscellaneous
Area of cockpit 2.9 ft^2 0,269m^2for cockpit template in plans (red)
Circumference 6.5 ft 1,98mcockpit
Depth in front 11.5 in 29,21cminside cockpit
Depth in rear 9 in 22,86cminside cockpit
Deck area 20.34 ft^2 1,889m^2includes cockpit area
Hull area 27.61 ft^2 2,56m^2 
Kayaker Fit & LoadingSmaller to madium size paddlers
130 lb min. -> 162 lb ideal -> 187lb max. (59 -> 74 -> 85,4kg)
Recommended max. load: 221lb (100,6 kg)
Paddler height: 6' and under (183 cm and under)
x=0 the start of waterline (DWL) at bow

All English units (ft / in) in the plans have a Metric (m / cm) equivalent !

.

Material

  Plywood
Unit converter
Metric / Standard unit converter

The minimum required plywood amount for the CirrusLT hull is 3 half sheets - 2' x 8' x 4mm marine plywood (60.96cm x 243.84cm x 4mm) or similar.
Minimum plywood thickness for hull: 4mm - 6mm max.

Notes & Tips:
  • What is Marine Plywood?
  • If you desire to make the kayak from different plywoods (more than one wood type/color), more sheets will be required. For example the dark deck plates of the Cirrus are made from Sapele veneer plywood which required one additional half sheet of plywood.
 Wood strips for deck
assumes bead & cove strips and you need either the 5/8" OR 3/4" strips. Not both.
 
Coverage + 'fudge factor' for wasteSurface area (ft2) (m2)Total length of 3/4" strips (ft) (m)Number of 3/4"x 16ft stripsTotal length of 5/8" strips (ft) (m)Number of 5/8"x 16ft strips
Total area of deck (+ cockpit)20.34  (1,88)391  (119)24488  (149)31
Total deck area + 5%21.35  (1.98)410  (125)26512  (156)32
Total deck area + 10%22.37  (2.08)430  (131)27537 (164)34

Notes & Tips:
  • 3/4" strip width = 1,9 cm
  • 5/8" strip width = 1,58 cm
  • 16 feet = 4,87 m
  • The accuracy of figures in the table is within (+ -) few feet
  • For custom calculation, see the Wood strip Calculator
  • The coverage based on the "+ 10%" is most recommended
  • Estimate wood for deck inlays as a percentage of the deck surface area
  • Ideal strip length is between 10 - 16 feet
  Fiberglass coverage
assumes complete coverage of inside and outside of hull and deck to make full sandwich core
 
Coverage of fiberglass
(plain weave e-glass)
yards
(yd)
feet
(ft)
meters
(m)
How to estimate
Deck - 4 oz. e-glass11.3 10,4two times the kayak length + 1 yard (1m)
Hull - 6 oz. e-glass 11.3 10,4two times the kayak length + 1 yard (1m)
2" wide glass tape 7121,6four times the kayak length + 9 ft (3m)

Notes & Tips:
  • Minimum width of fabric is 38" - will no allow for full hull abrasion patch
  • Order 50" width of the 4oz. glass to get the extra hull abrasion patch material
  • If 50" fabric is not available, order one 'waterline length - LWL' of additional cloth (any weight)
  • Round figures to the nearest higher number when ordering fabric
  • The 6oz. glass can always replace the 4oz.
  • See different types of reinforcement fabrics
  • Glass tape is sold in 'feet' and cloth in yards (in the US)
  • Glass tape is used to bond the kayak shells and for additional stem reinforcement
 Epoxy
 Minimum total volume of epoxy mix (resin + hardener): 2 to 2.5gallons

Notes & Tips:
  • Usage may vary (+-) 0.5 gallon as a result of the thickness of lay-up, fillet size, unused batches, spills, bad (unmixed) batches, care in application (overapplication), additional composite components such as coamings, hatch seals, rudders etc...
  • If epoxy is sold by weight, the density of epoxy is very close to water (1dm3 = 1 liter = 1kg)
  • 1 gallon = 3.8 liters
  • Learn about epoxy

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Last page update: 27 June 2014