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Old 10-25-2002, 11:18 AM
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Default Spacing of twin outboards

I am repowering my 1985 27 Whaler. Replacing the OMC Seadrives with an Armstrong bracket and a pair of 250 Yamahas. Current seadrives are on 30 inch centers, most twins seem to be on 28". I am considering going wider, 36". Any thoughs, pros, cons. If you have seen the ads for the new 314 Mako, the engines are mounted very wide.
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Old 10-25-2002, 11:30 AM
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Default Spacing of twin outboards

While I dont have twins and never had. I wonder if you space them too far apart would there be ventilation on the outside engine on sharp turns.

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Old 10-25-2002, 12:13 PM
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Default Spacing of twin outboards

Mine on my 2500 Hydra-Sports Vector are spaced 39" out. Great handling at the dock and great bite in rough water! I have an awesome Armstrong bracket and you may want to call Armstrong and ask then their input.
Steve
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Old 10-25-2002, 12:28 PM
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Default Spacing of twin outboards

You probably need to consider the deadrise at transom. The deeper the V, the more lower unit your going to have in the water as you spread them out creating more drag.
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Old 10-25-2002, 12:33 PM
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Default Spacing of twin outboards

The main thing is to make sure the cavition plate is even with the bottom of the hull, depper V boats will require closer placement while less agresive deadrise will alow for wider placement and better hanling at the dock, I have heard that closer placement may allow more speed, dont know if thats true.

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Old 10-25-2002, 01:10 PM
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Default Spacing of twin outboards

Steve25, did your boat come standard with a 39" setup or did you alter it. Do your engines sit really high?
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Old 10-25-2002, 02:04 PM
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Default Spacing of twin outboards

It was done right from the Hydra-Sports Factory! One neat thing on the Armstrong bracket is that my bracket has a deep-v in the bracket so it comes to a point at the bottom just like the hull. This prevents any water slap and spray when in a roling sea. Engines sit up fairly high as i have V-6 Johnsons, but nothing out of the ordinary...also helps them from getting soaked when backing down too. I can make a nice 180 degree turn with absolutely NO cavitation at all.

2500 Hydra-Sports Vector
Twin 225 Johnson Ocean Pro's
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Old 10-25-2002, 02:12 PM
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Default Spacing of twin outboards

Thanks Steve. Does anyone else run a wide setup like this? I have to order my bracket Monday.
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Old 10-25-2002, 02:23 PM
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Default Spacing of twin outboards

Sea Isle John that's not quite true on bracketed engines. The rule of thumb is. For every 12in of setback you raise the engine 1in. However it is true on transom mounts.

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Old 10-26-2002, 05:33 AM
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Default Spacing of twin outboards

NauticalSteve25...any chance you can post some pics of your setup?


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Old 10-26-2002, 06:41 AM
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Default Spacing of twin outboards

But the manufacturer of your OB's will actually "specify" some "minimums" for spacings, and they vary depending upon, how connected to controls..., control type and so on.
Best get your OB spacings specs before ordering the bracket to suit I'd suggest.
For example - not all twins are setup the same - some on cats are behind each sponson and very wide - connected with bull horns while some others on brackets can be quite close and connected with a tie rod etc..

Your Bracket people and yopur OB supplier should be giving you this information IMHO.

Cheers & good luck.

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Old 10-26-2002, 06:52 AM
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Default Spacing of twin outboards

On my Pursuit the Yami's props are 40" apart center to center. The boat has a 10'6 beam.
I think it depends on the boat design (ie... all the things metioned above)

The manufacturer of the bracket should be able to give you the maximum seperation for their product on your hull.
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Old 10-26-2002, 08:01 AM
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Default Spacing of twin outboards

Think Chorn 24's advice should be your most important considerations.
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Old 10-28-2002, 03:39 AM
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Default Spacing of twin outboards

Don't guess at this! call Armstrong and ask them what they manufacture for the particular model Whaler that you are installing it on. They will also give you exact demensions for mounting the bracket. I found them to be very helpful when I installed my bracket on a 1987 Hydra Sport 2500WA. let the experts tell you rather than guess.
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Old 10-28-2002, 06:32 AM
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Default Spacing of twin outboards

I will try to get some pics in the next week or so. I will have some tests done with different props too. Also, one IMPORTANT thing is that you must check inside your hull to make sure that the stringers which attach to the transom will clear the bolts when you mount the bracket. Many bolts go through the hull and check so that you do not have to cut your stringers and lose strength of the whole set up. Go with Armstrong. They can help you out quite a bit.

2500 Hydra-Sports Vector
Twin 225 Johnson Ocean Pro's
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Old 10-28-2002, 08:44 AM
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Default Spacing of twin outboards

Lew,
I'd be very interested in how you're boat turns out. We've got a 92 27' Walkaround that has the factory 250s mounted at 28" on the Whaler drive. The new F225 4 strokes require 28.5" to remove the cowlings properly and we've been debating what we're going to do when repowering. I love the idea of having them further apart for handling but was also concerned about cavitation on the outside motor while making sharp turns at high speed. I honestly don't think this would be a problem because the boat is not a deepvee 24 degree boat and does not turn like one. I also like the idea of being able to mount them a hole or 2 higher when spaced further apart.

Is your boat a factory full transom job with the original Whaler drive or did you convert it? Either way, are you going with a large step up from the hull bottom like most Armstrongs and the newer Whaler drives or are you building it with the full running bottom like the older Whaler drives? I see pros and cons with both and think that the running bottom may make a difference on how you space them.

Good luck. Please keep me informed of the out come and how the new motors perform. I'm assuming your going with the 250 HPDI's correct?
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Old 10-28-2002, 10:02 AM
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Default Spacing of twin outboards

Doghouse2, I am going to publish the entire repower process with photos on continuouswave.com. There is a lot of good information there on repowering Whalers. I am going with 250 EFI Yamahas, 2001 models. I don't want to be completely upside down on this boat. I am leaning toward a 36 inch center, but will know for sure later this week when I template the transom.
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