outboard bracket

janwillem · 18 October 2011, 03:07

I own a 22 foot Nautica with a pair of 90 hp etecs Evinrude. The engines are not bolted to the transom, but to a aluminium brackets that bolts to the transom. This bracket puts the engines about 25 cm aft. What is the reason for the bracket and secondly does it enhance or hinder the performance?

chewy · 18 October 2011, 06:21

It should give you more deck space and put the engines in cleaner water for better grip.
You don't see it too often on RIB's but on hard boats so people use gill brackets to convert it from inboard to outboard.

janwillem · 19 October 2011, 00:06

Thanks for the answer.

The only issue that i see is that it puts the center of gravity further aft and makes the bow ride higher.

captnjack · 19 October 2011, 00:59

Quote:

Originally Posted by janwillem

Thanks for the answer.

The only issue that i see is that it puts the center of gravity further aft and makes the bow ride higher.

On hard boats this is typically countered with trim tabs. Transom extensions, brackets or engine pods of various designs are extremely common here (probably 40% of boats have them). To some extent they make your hull behave like a larger boat.

janwillem · 19 October 2011, 01:06

do you think it has an effect on speed?

captnjack · 19 October 2011, 01:14

Quote:

Originally Posted by janwillem

do you think it has an effect on speed?

Depends on the hull. While trim tabs and/or trimming the engines down to keep the bow-rise under control (if any) lower speed, having clean water to the props is a big plus for speed. Most of the boats with them around here are fishing boats, not racing boats.

Is the hull unbalanced with the outboards on the brackets? Ryan Pratt on this boat has retrofitted several hulls from I/O to outboard, he's used brackets or engine pods. You might ask him why and how he gets the dimensions correct.

janwillem · 19 October 2011, 01:25

The boat doesn't ride with a high bow and it has trimtabs. For max speed I always trim up the engines, it increases the speed by almost 2 knots, but the boat feels unstable at that speed (42 knots). It appears the boat is wiggling on the water. The other disadvantage is that when the boat is stationary, the rib looks sternheavy

captnjack · 19 October 2011, 06:55

Did this used to be I/O powered? With a transom like this: Nautica 22 Jet Rib - See The Nautica 22 Jet Rib Todayq!
?