Deer Isle Koster (KDI)
Description
The Deer Isle Koster (KDI) is a versatile, lightweight sailing skiff designed by Bruce Elfstrom in 2009, inspired by traditional Scandinavian double-enders (Koster boats) but infused with modern catboat influences for family-friendly fun. Built primarily as a DIY kit by Chase Small Craft, it's optimized for youth sailors, beach launching, and "Swallows and Amazons"-style adventures—think swimming platforms, light-air performance, and easy reefing. With its wide beam, low freeboard, and balanced lug rig, the KDI excels as a row/sail hybrid for protected waters.
Construction Details
| Designer | Bruce Elfstrom |
|---|---|
| Builder | Chase Small Craft |
| Length | 14.000 ft |
| LOA | 14.000 ft |
| LWL | 12.500 ft |
| Beam | 5.830 ft |
| Displacement | 200 lb |
| Max Draft | 3.000 ft |
| Min Draft | 0.420 ft |
The standard boat dimensions
| i | - |
|---|---|
| j | - |
| p | - |
| e | - |
| p2 | - |
| e2 | - |
| i2 | - |
| j2 | - |
| I | J | P | E | P2 | E2 | I2 | J2 |
|---|---|---|---|---|---|---|---|
| - | - | - | - | - | - | - | - |
Documents
Blueprints
Sails
Deer Isle Koster (KDI) - JIBSAIL
| Luff | 10.443 ft - (3183 mm) |
|---|---|
| Foot | 4.099 ft - (1249 mm) |
| Leech | 8.813 ft - (2686 mm) |
| Length Perpendicular | * 3.39 ft - (1033 mm) |
| Area | * 17.69 ft² |
| Edit in Calculator | |
Deer Isle Koster (KDI) - JIBSAIL
| Luff | 11.208 ft - (3416 mm) |
|---|---|
| Foot | 3.698 ft - (1127 mm) |
| Leech | 9.67 ft - (2947 mm) |
| Length Perpendicular | * 3.08 ft - (939 mm) |
| Area | * 17.28 ft² |
| Edit in Calculator | |
Deer Isle Koster (KDI) - STANDING LUGSAIL
| Luff | 8.698 ft - (2651 mm) |
|---|---|
| Foot | 8.656 ft - (2638 mm) |
| Leech | 16.479 ft - (5023 mm) |
| Tack Angle | 82.5 ° |
| Diag (clew/throat) | * 11.44 ft - (3487 mm) |
| Head | 9.479 ft - (2889 mm) |
| Area | * 90.03 ft² |
| Edit in Calculator | |
Deer Isle Koster (KDI) - STANDING LUGSAIL
| Luff | 8.693 ft - (2650 mm) |
|---|---|
| Foot | 9.167 ft - (2794 mm) |
| Leech | 16.083 ft - (4902 mm) |
| Tack Angle | 75 ° |
| Diag (clew/throat) | * 10.88 ft - (3316 mm) |
| Head | 9.42 ft - (2871 mm) |
| Area | * 88.09 ft² |
| Edit in Calculator | |
Deer Isle Koster (KDI) - STANDING LUGSAIL
| Luff | 9.33 ft - (2844 mm) |
|---|---|
| Foot | 9.854 ft - (3003 mm) |
| Leech | 17.292 ft - (5271 mm) |
| Tack Angle | 76 ° |
| Diag (clew/throat) | * 11.82 ft - (3603 mm) |
| Head | 10.125 ft - (3086 mm) |
| Area | * 102.74 ft² |
| Edit in Calculator | |
Deer Isle Koster (KDI) - STANDING LUGSAIL
| Luff | 8.344 ft - (2543 mm) |
|---|---|
| Foot | 9.854 ft - (3003 mm) |
| Leech | 16.786 ft - (5116 mm) |
| Tack Angle | * 76.07 ° |
| Diag (clew/throat) | 11.276 ft - (3437 mm) |
| Head | 10.672 ft - (3253 mm) |
| Area | * 99.2 ft² |
| Edit in Calculator | |
Disclaimer. Boats are not all the same -- even when produced in the same factory of the same model. Sailrite does its best to publish accurate dimensions, but we often find it worthwhile to have our customers measure their boats carefully before we produce kits for them. You should take the same precautions, especially when the data is not from Sailrite. The information on this site is not guaranteed to be accurate. Sailrite offers this content as a service to our community, but takes no responsibility for the reliability of the data provided.