Short stagger / long stagger. Difference?

[scwten13]

Whats the difference between a long and short stagger? The distance from the transom to the engine? Also, is there a minimum distance the props need to be apart? Obviously they cant touch, but if they get too close will the boat slow down? I saw the Predator Apache 41 a long time ago and I could just get my thumb between the props. I am a lurker of sorts here, no boat, but I enjoy reading the posts you guys put up. Always learn something new.

 

[DKwestern]

I "think" full stag is 18" centers and short stag is 24" centers most of the time.

 

[Ted]

A long stagger means the engine have no overlap front to rear and can be placed as close as possible together. A short stagger means the engines are overlapped front to rear some, but they are closer together than a typical side by side because of exhaust system clearance. Each hull reacts differently but many boats can have the props almost touching and gain some speed, just don't try and dock them :sifone:

 

[DAREDEVIL]

I "think" full stag is 18" centers and short stag is 24" centers most of the time.

:iagree:

 

[DAREDEVIL]

A long stagger means the engine have no overlap front to rear and can be placed as close as possible together. A short stagger means the engines are overlapped front to rear some, but they are closer together than a typical side by side because of exhaust system clearance. Each hull reacts differently but many boats can have the props almost touching and gain some speed, just don't try and dock them :sifone:

 

[Jassman]

A long stagger means the engine have no overlap front to rear and can be placed as close as possible together. A short stagger means the engines are overlapped front to rear some, but they are closer together than a typical side by side because of exhaust system clearance. Each hull reacts differently but many boats can have the props almost touching and gain some speed, just don't try and dock them :sifone:

Here's a short stagger..and I'm still laughing on the docking situations..especially when it's windy...and it's worse when the props spin in:willy_nilly:..one foward, one reverse start your spin, give the reverse some juice, and bump in and out the one forward to help the spin pivot...some days were better than others..oh ya...make sure the drives were not all the way tucked in..keep them neutral, level with boat so less water off transom ...then say a prayer, and make sure have good boating babes..

 

[DollaBill]

Here's a short stagger..and I'm still laughing on the docking situations..especially when it's windy...and it's worse when the props spin in:willy_nilly:..one foward, one reverse start your spin, give the reverse some juice, and bump in and out the one forward to help the spin pivot...some days were better than others..oh ya...make sure the drives were not all the way tucked in..keep them neutral, level with boat so less water off transom ...then say a prayer, and make sure have good boating babes..

hahaha

 

[phragle]

The difference between a short stagger and a long stagger is about 6 shots.....

 

[scwten13]

Good stuff, thanks. So, why isn't it called narrow and wide stagger? In a full race boat a short stagger would be best because the drives are closer and lower, right? Are there any books or articles about setup for drives and engines?

 

[Chris]

Short because the two engine package is shorter on the short stagger than the full stagger. On a full, the one engine is behind the other and offset to the side.

Staggering does a couple of things. First it allows the engines to be set deeper in the hull, giving you a lower center of gravity. They get fed cleaner water so the props bite better and on 18" centers, they're essentially driving one column of water which is more efficient.

As was said, the downside can be decreased dockside maneuverability. Also, you find full stagger primarily on race boats which means crash boxes, So not being able to shift with the engines running makes docking even more fun.

 

[scwten13]

Makes sense. Predator had crash boxes, interesting to have to stop, change gears, and restart. Is the trans mounted directly behind the engine or on the transom? Did I read correctly that a lot of the European race boats have 3 or 4 speed transmissions?

 

[Chris]

The setup is the same for transmission and crash box boats. You have the engine with a flywheel, a bellhousing that the starter mounts to and the gearbox. The space for the box is universal. You can remove one type and replace it with another.

With staggered setups, you typically have one driveline gimbal and one plug-in. The rear engine uses the plug-in and a driveshaft connects to a yoke on the trans output shaft and a flange on a bearing carrier in the other gimbal.

 

[xlr8by]

I have a great respect for guys that run crash boxes and dock them especially in tight situations with WIND! I was on a 41' Apache once with wind and crash boxes and a tight dock. The owner never flinched, and was a pro, but if you hesitate or the motor doesn't start it could have been a big problem very quickly! Chris I didn't ask, but what would happen if you try and throw the boat from reverse into forward with crash boxes? I assume you would ruin the grears?

 

[MOBILEMERCMAN]

I wouldn't think the shift lever will move with a load on it.

The full stagger thing is a relative term without a distinct definition IMO.

To me a full stagger would have two drivelines and would have both motors in line with drives. That takes about 110 inches to accommodate. In this case the prop diameter is the limiting factor when choosing center lines. I think available space is the deciding factor in most cases.

 

[Chris]

It would be just like attempting to shift any unsynchronized gearbox. Without much load you can get them to disengage, but it's not all that great on the teeth. You're probabaly not going to get one gear turning 1000 rpm and one turning zero to mesh without using the edges of the teeth to spin the idle one up. And with an immersed propeller and the drag of the outdrive, that's probably not going to happen.

 

[Chris]

In this case the prop diameter is the limiting factor when choosing center lines. I think available space is the deciding factor in most cases.

If I recall, the #6 gimbal is too wide to get anthing less than 18" centers.

 

[Perlmudder]

It would be just like attempting to shift any unsynchronized gearbox. Without much load you can get them to disengage, but it's not all that great on the teeth. You're probabaly not going to get one gear turning 1000 rpm and one turning zero to mesh without using the edges of the teeth to spin the idle one up. And with an immersed propeller and the drag of the outdrive, that's probably not going to happen.

So on boats with crash boxes the starters are crazy powerful so that they can turn the engine, tranny, outdrive and prop?

 

[Chris]

Sometimes they use two.

 

[Ted]

So on boats with crash boxes the starters are crazy powerful so that they can turn the engine, tranny, outdrive and prop?

Yes, and there are a whole bunch of new high torque starters with internal planetary gears that can spin up these big blower motors. A buddy of mine has shifter mounted buttons to fire the engine after shifting into whatever gear he choses when the engine is off. If you leave the ignition turned off you can do a pretty good job of moving the boat (40 Skater) with a blip of the starter only.

 

[scwten13]

Is it best to have the bullet of the drive in line with the bottom of the hull at neutral trim? If so, are the props "surface piercing?