Review of Tumlaren
Basic specs.
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The hull is made of wood.
The boat is equipped with 4 berths.
The Tumlaren is equipped with a fractional rig. A fractional rig has smaller headsails which make tacking easier, which is an advantage for cruisers and racers, of course. The downside is that having the wind from behind often requires a gennaker or a spinnaker for optimal speed.
Full keel
The Tumlaren is equipped with a long keel. A full keel provide a better directional stability than a similar boat with a fin keel; on the other hand, better directional stability means also that the boat is more difficult to handle in a harbour with less space.
The keel is made of lead. Compared with iron, lead has the advantage of being 44% heavier, which allows a smaller keel and hence less water resistance and higher speed.
The boat can enter even shallow marinas as the draft is just about 1.30 - 1.40 meter (4.27 - 4.57 ft) dependent on the load. See immersion rate below.
Sailing characteristics
This section covers widely used rules of thumb to describe the sailing characteristics. Please note that even though the calculations are correct, the interpretation of the results might not be valid for extreme boats.
What is Capsize Screening Formula (CSF)?
The capsize screening value for Tumlaren is 1.56, indicating that this boat could - if evaluated by this formula alone - be accepted to participate in ocean races.
What is Theoretical Maximum Hull Speed?
The theoretical maximal speed of a displacement boat of this length is 6.2 knots. The term "Theoretical Maximum Hull Speed" is widely used even though a boat can sail faster. The term shall be interpreted as above the theoretical speed a great additional power is necessary for a small gain in speed.
The immersion rate is defined as the weight required to sink the boat a certain level.
The immersion rate for Tumlaren is about 84 kg/cm, alternatively 470 lbs/inch.
Meaning: if you load 84 kg cargo on the boat then it will sink 1 cm.
Alternatively, if you load 470 lbs cargo on the boat it will sink 1 inch.
Sailing statistics
This section is statistical comparison with similar boats of the same category. The basis of the following statistical computations is our unique database with more than 26,000 different boat types and 350,000 data points.
What is Motion Comfort Ratio (MCR)?
The Motion Comfort Ratio for Tumlaren is 23.5.
What is L/B (Length Beam Ratio)?
The l/b ratio for Tumlaren is 4.37.
The ballast ratio for Tumlaren is 51%.
What is Displacement Length Ratio?
The DL-ratio for Tumlaren is 179 which categorizes this boat among 'light racers'.
What is SA/D (Sail Area Displacement ratio)?
The SA/D for Tumlaren with ISO 8666 reference sail is 14.4, with a 135% genua the SA/D is 16.0.
What is Relative Speed Performance?
The Relative Speed Performance for Tumlaren is 27
Maintenance
When buying anti-fouling bottom paint, it's nice to know how much to buy.
The surface of the wet bottom is about 16m2 (172 ft2).
Based on this, your favourite maritime shop can tell you the quantity you need.
Note: If you use a paint roller you will need more paint than if you use a paintbrush.
Dimensions of sail for fractional rig.
Are your sails worn out? You might find your next sail here: Sails for Sale
If you need to renew parts of your running rig and is not quite sure of the dimensions, you may find the estimates computed below useful.
| Usage | Length | Diameter | ||
| Mainsail halyard | 25.1 m | (82.2 feet) | 8 mm | (5/16 inch) |
| Jib/genoa halyard | 25.1 m | (82.2 feet) | 8 mm | (5/16 inch) |
| Spinnaker halyard | 25.1 m | (82.2 feet) | 8 mm | (5/16 inch) |
| Jib sheet | 8.3 m | (27.2 feet) | 10 mm | (3/8 inch) |
| Genoa sheet | 8.3 m | (27.2 feet) | 10 mm | (3/8 inch) |
| Mainsheet | 20.8 m | (68.1 feet) | 10 mm | (3/8 inch) |
| Spinnaker sheet | 18.3 m | (59.9 feet) | 10 mm | (3/8 inch) |
| Cunningham | 3.1 m | (10.1 feet) | 8 mm | (5/16 inch) |
| Kickingstrap | 6.2 m | (20.3 feet) | 8 mm | (5/16 inch) |
| Clew-outhaul | 6.2 m | (20.3 feet) | 8 mm | (5/16 inch) |
This section is reserved boat owner's modifications, improvements, etc. Here you might find (or contribute with) inspiration for your boat.
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