Choosing engine power, rules of thumb and the licence limit
At displacement speed, four to six PS per tonne are enough; planing needs several times that.
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A displacement boat gets by on little power, because it will not go any faster than its hull speed anyway. Four to six PS per tonne are enough for cruising speed and still leave a reserve against current and wind. Planing follows different rules, where you are looking at thirty PS per tonne and upwards.
For motor boats, engine power determines the premium. It also decides whether you need a licence: above fifteen PS you must hold the German Sportbootführerschein for the waters you are on.
Important if you fit a more powerful engine: that is an increase in risk and must be notified. If you keep quiet about it, you risk the insurer refusing to pay, and that will be exactly the claim where the new engine caused the damage.
Frequently asked questions
Do I have to report a more powerful engine?
Yes. More power is an increase in risk and must be reported; otherwise the insurer can refuse to pay.
How many PS does a displacement boat need?
Four to six PS per tonne for cruising speed with a reserve.
Worked out for your type of boat
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