The **J/105** is a 34’5” (10.5m) racer-cruiser sailboat designed by *Rod Johnstone* (United States). She was built since 1991 (and now discontinued) by *J/Boats* (United States).

The**J/105** is as well listed, on Boat-Specs.com, in Shoal draft version (see all the versions compared).

The

- Model
- J/105
- Version
- Standard
- Hull type
- Monohull
- Category
- Racer-cruiser sailboat
- Sailboat builder
- Sailboat designer
- Country
- United States
- Construction
- GRP (glass reinforced polyester):

Sandwich fiberglass polyester - First built hull
- 1991
- Last built hull
- Discontinued
- Appendages
- Keel : L-shaped keel (with bulb)
- Helm
- Single helm wheel
- Rudder
- Single spade rudder
- Unsinkable
- No
- Trailerable
- No
- EC design category
*iThe CE design category indicates the ability to cope with certain weather conditions (the sailboat is designed for these conditions)*

A: Wind < force 9, Waves < 10m

B: Wind < force 8, Waves < 8m

C: Wind < force 6, Waves < 4m

D: Wind < force 4, Waves < 0,5m - A
- Standard public price ex. VAT (indicative only)
- N/A €

- Hull length
- 34’ 5”10.5 m
- Waterline length
- 29’ 6”8.99 m
- Beam (width)
- 11’3.35 m
- Draft
- 6’ 6”1.98 m
- Mast height from D
_{WL} - 50’ 4”15.34 m
- Light displacement (M
_{LC}) - 7749 lb3515 kg
- Ballast weight
- 3417 lb1550 kg
- Ballast type
- Lead
- French customs tonnage
- 8.81 Tx

- Upwind sail area
- 577 ft²53.6 m²
- Downwind sail area
- 1305 ft²121.2 m²
- Mainsail area
- 304 ft²28.2 m²
- Solent area
- 273 ft²25.4 m²
- Asymmetric spinnaker area
- 1001 ft²93 m²
- I
*iFore triangle height (from mast foot to fore stay top attachment)* - 40’ 7”12.37 m
- J
*iFore triangle base (from mast foot to bottom of forestay)* - 13’ 6”4.12 m
- P
*iMainsail hoist measurement (from tack to head)* - 41’ 6”12.65 m
- E
*iMainsail foot measurement (from tack to clew)* - 14’ 7”4.45 m
- Rigging type
- Sloop Marconi fractional
- Mast configuration
- Keel stepped mast
- Rotating spars
- No
- Number of levels of spreaders
- 2
- Spreaders angle
- Swept-back
- Spars construction
- Aluminum spars
- Standing rigging
- Single-strand (ROD)

- Upwind sail area to displacement
*iThe ratio sail area to displacement is obtained by dividing the sail area by the boat's displaced volume to the power two-thirds.*

The ratio sail area to displacement can be used to compare the relative sail plan of different sailboats no matter what their size.

Upwind: under 18 the ratio indicates a cruise oriented sailboat with limited performances especially in light wind, while over 25 it indicates a fast sailboat. - 250 ft²/T23.19 m²/T
- Downwind sail area to displacement
*iThe ratio sail area to displacement is obtained by dividing the sail area by the boat's displaced volume to the power two-thirds.*

The ratio sail area to displacement can be used to compare the relative sail plan of different sailboats no matter what their size. - 564 ft²/T52.43 m²/T
- Displacement-length ratio (DLR)
*iThe Displacement Length Ratio (DLR) is a figure that points out the boat's weight compared to its waterline length. The DLR is obtained by dividing the boat's displacement in tons by the cube of one one-hundredth of the waterline length (in feet).*

The DLR can be used to compare the relative mass of different sailboats no matter what their length:

a DLR less than 180 is indicative of a really light sailboat (race boat made for planning), while a DLR greater than 300 is indicative of a heavy cruising sailboat. - 137
- Ballast ratio
*iThe Ballast ratio is an indicator of stability; it is obtained by dividing the boat's displacement by the mass of the ballast. Since the stability depends also of the hull shapes and the position of the center of gravity, only the boats with similar ballast arrangements and hull shapes should be compared.*

The higher the ballast ratio is, the greater is the stability. - 44 %
- Critical hull speed
*iAs a ship moves in the water, it creates standing waves that oppose its movement. This effect increases dramatically the resistance when the boat reaches a speed-length ratio (speed-length ratio is the ratio between the speed in knots and the square root of the waterline length in feet) of about 1.2 (corresponding to a Froude Number of 0.35) . This very sharp rise in resistance, between speed-length ratio of 1.2 to 1.5, is insurmountable for heavy sailboats and so becomes an apparent barrier. This leads to the concept of "hull speed".*

The hull speed is obtained by multiplying the square root of the waterline length (in feet) by 1.34. - 7.28 knots

- Engine(s)
- 1 inboard engine
- Engine(s) power
- 20 HP
- Fuel type
- Diesel
- Fuel tank capacity
- 11.9 gal45 liters

- Cockpit
- Closed aft cockpit
- Cabin(s)
- 1
- Berth(s) (min./max.)
- 2 / 5
- Head(s)
- 1
- Holding tank capacity
- 11.9 gal45 liters

Sailboats

First built hull

Hull length

2004

40’12.19 m

2017

40’12.2 m

2016

34’ 10”10.6 m

2009

34’ 1”10.4 m

2019

32’ 7”9.94 m

2007

32’ 1”9.78 m

2004

32’ 10”10 m

1984

35’ 8”10.87 m

1991

34’ 5”10.5 m

2006

34’ 8”10.59 m

1997

31’ 2”9.5 m

2001

35’ 4”10.75 m

2012

36’ 5”11.1 m

2013

35’ 5”10.8 m

2006

40’12.19 m