Elegant, luxurious and absolutely sea-worthy!
The Shearwater 890 CC is an open-cabin rib with excellent build quality and finish, which in combination with its extremely dry and soft cruising rank it at the top of its class.
It was the first time that Shearwater was powered by twin DF 175AP Suzuki engines and that in itself was a challenge for a sea trial.
On the day of our test, the wind speed did not exceed 12 knots while the ripple did not reach one meter height. Under these conditions, we had no problem maintaining high speeds and enjoying the velvet damping of the Shearwater’s hull.
Our impressions from this new set-up were excellent, with strong accelerations at medium rpm and without significant differentiations in its behavior compared to single-engine applications.
The description of the deck and our overall view of the Shearwater 890 CC ride capabilities you can see in our previous article: Shearwater 890 CC
Suzuki's engines with Full Throttle Operating Range of 5500-6100 and a reduction ratio of 2.50: 1, which is the largest gear ratio in their class, were turning 14 5/8΄΄ x 23΄΄ Revolution four-blade stainless steel propellers.
With two people on board and 350 liters of fuel, the Rib was standing on plane at 2500 rpm, maintaining a speed of 11.5 knots.
At 3000 rpm our speed was 17.5 knots with a fuel consumption of 1.7 liters per nautical mile, while at 3500 rpm we were running at 24 knots burning 1.6 liters per mile recording the most economical cruising speed.
At 4000 rpm we were traveling with 29 knots consuming 1.7 liters per nautical mile, recording a slip percentage of just 4.3%, while at 4500 rpm the slippage decreased further and reached an astonishing percentage of 1.5% giving us 33.5 knots and fuel consumption of 1.8 liters per mile.
The above slip numbers indicate an excellent set-up and a great combination of propellers-engine mounting heights, resulting to get almost all the theoretical speed of our propellers when traveling at medium rpm.
As much as engines’ speeds were increased the slip percentages were decreased, so at the wide open throttle we recorded "negative" slip numbers, due to both the tall cup of our propellers and the fact that two propellers were running to cover the same distance at the same time.
You can see the detailed measurements in the following table:
It would be really interesting to try the Bravo I LT 15 ¼΄΄ x 24΄΄ propellers, which have shown that they fit perfectly with the single-engine Shearwater, remaining at about the same rpm at WOT and improving the ride quality and our performance at midrange rpm.
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