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Why Offshore Brackets?

99K views 78 replies 42 participants last post by  Paddler 
#1 ·
I need an education on offshore brackets. What is their purpose? I always thought it best to have engine weight as close to the center of buoyancy as possible. An inboard with engine amidships is best,an outboard on the transom is not as good. But an offshore bracket puts all that engine weight even farther back, thus making the stern sink lower than it would with a transom mount.

Also, it is difficult to fish around the engines.

I see a lot of offshore brackets, so there must be some benefits. What are those benefits?
 
#2 · (Edited)
actually on an outboard boat the center of gravity needs to be behind the back 1/3 of the hull to be ballanced for best ride, fastes hull speed, best handeling and wave cutting ability, as the hull planes off the center of gravity moves back, and the farther back the bulk of the weight is the easier the hull can lift, the more efficient they get and the better they ride.


remember teeter totters in grade school.... the boat is a big kid on one end, and the engine is thhe skinny squirt on the other..... to ballance the teeter totter, the little kid needs a longer fulcrum arm to ballance the larger body... as most hulls weigh 1400+ lbs, and outboards weigh between 350 and 600 for the average HP outboard. in order for forces to ballance out the engine needs moved back enough in order to carry the hull....

inboards can do this inside the hull because they weigh over 800lbs when you combine the leg and the engine assemblies... big blocks weigh as much as 1250 lbs for high HP blower equipped motors....

this is why extended transoms are a waste of time, hull length and overall benifit of an offshore bracket, sure the engine is back from the percieved transom of the boat, but if the bottom extends with the bracket the motor only sees a 2 ft longer hull and none of the leverage gained by the engine being set away from the cockpit area. all other hulls except NW built aluminum hulls are actually building notched transoms that build in the set back into the bottom of the boat so a very short if any aditional setback is needed where a extended transom would need an aditional 18-20" of engine to hull setback to see any gains a bracket gives to a hull....


the major issues many people see is porpose. spray, and poor at cruise handeling, all are caused by incorrect engine to hull set up... the motor is to low, propeller incorrect for the hull and trim is set incorrectly. or any combination of all 3....


there are a couple rules that local MFG and dealers dont follow when setting up a boat for ideal performance of an engine and hull combination...

for standard mono hulls a ratio of 12:1 boat length to engine set back is basically standard starting point.... beiing that for every foot of hull you want 1 " of distance from your hull to the front of the gearcase. and every 6 inches back from hull the cavitation plate of the engine can raise 1 inch up. so on a 22 ft boat you want 22" of distance from the end of the bottom to the front of the gearcase with the boat and engine level, and at 22" back the engine can go up 3.5" over baseline engine height without any ill effects of excessive height.

enter rule number 2

below 50 mph... the hull baseline may move down as much as 2 inches from the above rule, at 50 mph the rule fits true and true, and for every 10 mph above 50 the engine can go up another inch untill the gearcase losses cooling water pressure.

at 80+ mph the whole equasion changes and starts dropping again due to the speed at which you are traveling, in this case most hulls apply to the rule of 6.5" up unless they are very light and can carry themselves naturally without engine leverage through trim.. in which the engine can continue to rise as long as the engine stays cool, and speeds still increase.



long winded but there is no short answer


and for the record 99% of the hulls seen in the NW are NOT offshore bracket equipped... but are EXTENDED TRANSOM units AKA floatation brackets which are nothing more than a joke and waste of time
 
#4 ·
here is a photo of one of those "nothing more than a joke and waste of time brackets"..having safely put in 3K hours of running the offshore haunts of WCVI..oh and the same bracket the US Navy, national marine Fisheries, & countless AK guides use...by the hundreds..



The "point" is many -fold

1.) More room in the boat
2.) properly designed, which means by an Engineer as this bracket was - has the proper bottom extension where lift is maximized and drag minimized - hint, in this application its a 2 degree Camber
3.) Modern 4-stroke V6 O/B's start above 400#, bouyancy in the bracket, ALL the time is a BIG plus. It enables self bailing..duh
4.) ZERO porpoise issues
5.) Full height transom coupled with #3 makes the boat a real following sea performer, I can verify this - with My and 3 other lives in a nasty blow.
6.) notch the transom, lengthen the hull and carry more weight with a splashwell that takes up space and may ship water

7.) ????

Only minus I can see is the boat is not optimized for speed, which really is not the point of ifish, is it.
 
#6 · (Edited)
here is a photo of one of those "nothing more than a joke and waste of time brackets"..having safely put in 3K hours of running the offshore haunts of WCVI..oh and the same bracket the US Navy, national marine Fisheries, & countless AK guides use...by the hundreds..

The "point" is three-fold

1.) More room in the boat
2.) properly designed, which means by an Engineer as this bracket was - has the proper bottom extension where lift is maximized and drag minimized - hint, in this application its a 2 degree Camber
3.) Modern O/B's start above 400#, bouyancy in the bracket, ALL the time is a BIG plus.
4.) ZERO porpoise issues
5.) Full height transom coupled with #3 makes the boat a real following sea performer, I can verify this - with My and 3 other lives in a nasty blow.
6.) notch the transom, lengthen the hull and carry more weight with a splashwell that takes up space and may ship water

8.) ????

Only minus I can see is the boat is not optimized for speed, which really is not the point of ifish, is it.
point 1 same room null in void
point 2.. ROCKER CAUSES PORPOSE and poor handeling and a 2 degree angle is just that hull rocker not a clean break for water to rise from

Point 3
mercury 280 hp was built untill 2005 and weighs 375, many 75.90, 115s are sub 400 lbs... null in void...

point 4.. obviously you never been fast enough to pull a hull onto the rocker of the bracket... null in void

point 5. null in void.... the bracket boats are also full transom...

6 no splash well you already said that....





so what were all your benifits........


i fail to see any... and it isnt always about speed..... its about being efficient...

look at the older north rivers, older alumawelds, original almars, and all the east coast built hulls.. NONE had ET hulls and all have all the features you just mentioned... and if they are designed PROPERLY, not just a slapped on welded piece of .190 skin with a 2x4" c channel are actually stronger than an ET.. because they pass through the hull into the stringers..


tomictime, if you were to craft off the bottom 12" of that bracket the boat wouldnt change one bit internally, the hull would be lighter on the water and have a better rough water ride as the bow can rise over things normally pounded through because of the extended hull length.. the extra area from the engine to the actual transom and end of hull will allow air bubbles to clear the prop gaining leverage, and propeller bite... its not a question of better or worse... its a common physics equasion.... XYZ weights takes XYZ leverage to raise.. more than XYZ leverage and effecincy drops due to pushing water down instead of back... same with less than XYZ leverage.. your pushing water up not out.... so in either scenerio you end up using more fuel than needed, more trim than iddeal (+ or -) and because the propeller blade is not paralell to the water it losses forward thrust due to blade slipage due to excessive running angle.
 
#5 ·
I agree with Tomictime. I have one because I get a 25' boat length with a 22' boat -- no inside room used by the motor. I had a little popoising problem when I first bought it, but learned how to trim it properly so no problem now. My kids really like the platform when they're skiing. It's a little tougher landing bigger fish because you have to work around the motors, but I use longer rods with this boat to compensate.

I like the ride and more room allowed with the extended transom, but that's just my :twocents:, so it's worth what you pay for it.

IMHO, the best thing to do is to test ride a bunch and find one that feels good for you.
 
#7 ·
I think you mean null and void. Normally at that point, I would quit

My response was to Tin man, who has a lot of ? about the value of any extended bracket..but I think some of your retorts merit a response:

this is an older almar, lets see some 15 years now. Boat designs change. real world testing by a world champion jet boat racer (former Almar VP, and a real engineer proved this out, if you can do better have at it. I am sure the Navy awits you.

Many hulls with close to zero rocker have dynamic instability issues related to offset brackets, I ran a V-20 steplift with a Gil bracket.

Think about it, rocker is a curve. Trim tabs are not rocker.


The nearly 1/2 " stem bar extends thru the bracket, and I have seen the way the stringers, transom, U channel bracing and stem bar transition are engineered - just looked at the construction pics today to help a fellow ifish'r out who is converting his I/B to floation / running surface..and I was there when it was built.

The engines you mention are rare and getting rarer, I recall using the word "modern"
 
#8 ·
Did I just bite my tongue again cause this one post has taken me 1 hour to write,,,,man there it went again ouch,,,,18 post / 3,231 post. Guess if I knew it all I would not be biting my tongue like this and would explane why I knew more ,,,,Raptor Raptor get a camera plz I would like to see some shots of all the xyz you have . Nice boat Tomictime, ,,,,can't waite to see how this plays out,,,,HAVE FUN AND BE SAFE
 
#9 ·
Having the engine amidships makes the boat more stable for putting along, but for speed you want as little of the hull as possible touching the water. Offshore brackets came about primarily to allow a full-height transom and secondarily to increase the room in the boat. The problem with them was that when 4-strokes replaced 2-strokes the back end of the boat started sitting too low. Also, the quality of the water flowing to the prop varied greatly depending on speed. Extending the hull under the offshore bracket greatly helps solve problems of the offshore bracket but as a trade-off you loose a bit of top-end speed and on-plane stability.

My boat has an extended hull and I love it. The advantages greatly outweigh the disadvantages for the ways in which I use my boat. I have found:
1. It completely frees up the stern of the boat and gives a lot more room to fish.
2. The buoyancy pod keeps the rear end of the boat up and helps float the 600lb 4-stroke and 120lb kicker.
3. Full height transom means I never have to worry about taking a wave over the stern or having a young kid fall out the back.
4. The boat has a 21' hull as far as registration/insurance is concerned, but the boat really rides like a 23' hull.
5. I can turn sharper at high speeds than with an offshore bracket. I the boats I tested without the extended hull the prop seamed to break loose easier as I trimmed up at high speed.

Does the offshore transom get in the way of landing fish? Not really anymore than any other outboard powered boat.

Also, as for raptor700r's remarks: You really shouldn't type drunk buddy. We need an occasional capital letter and some punctuation to go along with a little more coherancy in your writing if you want us to understand most of what you write.
 
#10 · (Edited)
Honest observations :

The good

Planning out of the hole:

I like my OS bracket for easy jumping on plane. Contrary to what many may think, the extra 2.5 feet is a stabilizing force for quick easy plane. My old boat (non-OS bracket) was a pig out of the hole and I viewed my Bow for way longer than need be.

Rough waves and chop:

Self explanitory there, out on the Big-C I do not get the transom spray and water I used to.

More room:

Possibly the biggest benefit.

The bad

Steering:

Less control than boats without an OS bracket, expect your turn radius to suffer. It did not work very well using a kicker rod for steering either, you just do not have as much "side to side" control in the back. Easily improved and perfected by my TR-1, but more $$$$.

"My OWN" Conclusion

After having both styles of transoms, we will continue to see more and more Boat manufacturers go this direction. The exception possibly being a quick & nimble lake sized boat.
 
#11 ·
Why, when there is disagreement do we start comparing the size of our post numbers and start attacking someone personally?
Is it possible that a new member might come along and be a rocket scientist.

From my observations, number of posts or proper typing skills is no indication of intelligence. I have no dog in this fight,but I did want to see a discussion of differing opinions on off shore brackets.

Thanks for letting me vent. :D
 
#12 ·
Raptor's points seem to be closely tied to the world of higher speed, performance type hulls. His information rings true in that world. However, attacking every heavy gauge builder who chooses to use an extended transom, or a true offshore bracket, seems a bit far fetched.
The general public tends to express themselves best with their wallets...and the sheer number of heavy gauge vessels on the water running some type of bracket or bottom extension make it clear that the benefits are real.
 
#13 ·
Ahh, you gotta love Ifish for just these types of discussions! Wish I could weigh in with some data, but it will be awhile before it comes. I am the guy Tomictime is talking about who is adding an offshore bracket to my boat. As soon as it is done, I can at least provide a real world comparison between how it performs with an inboard versus the outboard and offshore bracket.

Going to be a big change - taking almost 1200 lbs out of the boat with most of that weight down low and adding back about 700 lbs with the bracket and Suzuki 300 out back. I am pretty sure that without the added flotation the change in balance would cause porpoising, but will never know cause the welding is in process. :meme:
 
#14 ·
I fished with a guide in Alaska with an offshore boat and bracket, when a couple of large halibut that we hooked went behind the boat and he lifted the engines so we could swap sides I was amazed but not sold, that wasn't until we were out in some bad weather and the boat handled awesome. If you go to Yakutat Alaska to offshore fish I reccomend you contact Tim Ross!
In 07 I bought a Seahawk with the offshore bracket and absolutely love it.:twocents:
 
#15 ·
I need an education on offshore brackets. What is their purpose? I always thought it best to have engine weight as close to the center of buoyancy as possible. An inboard with engine amidships is best,an outboard on the transom is not as good. But an offshore bracket puts all that engine weight even farther back, thus making the stern sink lower than it would with a transom mount.

Also, it is difficult to fish around the engines.

I see a lot of offshore brackets, so there must be some benefits. What are those benefits?
Tinman, the main page also has a thread on this topic.

One point not mentioned, and it's a lesser benefit but I still enjoy it -- QUIET. With the outboard placed out there beyond and a bit below the height of the transom, it really reduces the motor noise within the boat. For those long offshore runs, it's nice to have a converation at normal levels and not be yelling over motor noise.

The bracket's flat surface is also convenient for setting bleed buckets and bait containers on.
 
#17 ·
and all the time bouyancy and a better ride.

a set-back bracket, when combined w a jack plate is faster.

What I am hearing is that the main advantages are: 1) more room in the boat, and 2) full-height transom.

Beyond that, there is little consensus on the performance pros and cons. I'm not in the market for a bracket, but am just curious
 
#18 ·
Having run my old 22' Seahawk with an 05 bracket and then a new bottom extension bracket, the new bracket made the 22' feel and perform like a 24'. Ride smoothed out, porpoise went away, and the whole boat was better. Should have never sold it. It was a new boat after getting the bottom extension. Jay Conn helped test it before and after and there was no comparison so it was not just me thinking there had been an improvement.
 
#19 ·
Most all boats are a compromise of something. Offshore brackets are a fix for problem in design. Extended transoms the same. Trim tabs the same unless you are using them to balance side to side. Most mass produced boats are not designed to balance with different motor configurations so you have design problems in balance to fix. Raptor700r's comments on hull design are true with a purpose designed boat. An offshore bracket properly done without the transom extension gives the motor more leverage on the boat and can enhance performance. This also can act as a jackplate without notching the transom.

Your boat may perform better for what you do with an offshore bracket with a transom extension. I have done or envisioned many changes in hull design for stability or balance. I had a boat custom built that after lake tests the builder wanted to put 150 pounds of lead plate in the transom to correct a balance issue. Trim tabs create heavy drag to bring your bow down.
 
#23 ·
Every good boat is a purpose designed boat with compromises.

Extended brackets, running surface or not are design decisions.

1.) Leverage has very little to do with any + attribute of any extended bracket:

The design requirements are: room in the boat without all the added cost, a full transom, bouyancy: full-time or partial and with a non-running surface bracket, the ability to mount the prop higher and achieve potentially higher speeds.

The ability to mount the prop is caused by one relationship: distance from the aft planning surface and the prop, the bracket GIL or otherwise is how you get that relationship.

Porpoise is easy to understand, imagine an undamped teeter totter vs on with with springs, the bow is damped in each design scenario, the transom is not. Proper balance is an important attribute no matter what design.

As for trim tabs, absurd that they correct a design deficiency in most planning hulls. wind and wave list and head sea running almost always require prudent usage of tab.

Most all boats are a compromise of something. Offshore brackets are a fix for problem in design. Extended transoms the same. Trim tabs the same unless you are using them to balance side to side. Most mass produced boats are not designed to balance with different motor configurations so you have design problems in balance to fix. Raptor700r's comments on hull design are true with a purpose designed boat. An offshore bracket properly done without the transom extension gives the motor more leverage on the boat and can enhance performance. This also can act as a jackplate without notching the transom.

Your boat may perform better for what you do with an offshore bracket with a transom extension. I have done or envisioned many changes in hull design for stability or balance. I had a boat custom built that after lake tests the builder wanted to put 150 pounds of lead plate in the transom to correct a balance issue. Trim tabs create heavy drag to bring your bow down.
 
#20 ·
I almost forgot 1.

They make a great swim platform and cooler shelf in the summer too !

Easy to jump in/dive in and my dog gets up into the boat easier also.

:meme:


"I" dont think the design is going away anytime soon peeps.
 
#21 ·
I recall a picture posted here last year that had an unfortunate guy get his anchor line wrapped around his prop while fishing the Big C. The boat had flipped around, transom to the current, and he had the motor tipped all the way up to try to free the line. Without an offshore bracket, that boat would have been at the bottom of the river.

That really made me NOT want to anchor fish!
 
#22 ·
I hear ya 100% :yeahthat:

When on anchor I actually take the extra time amd might to pull up anchor by hand rather than using the Ball/lift method.

I freely admit most guys are very good at using the anchor lift systems. I just do not want to be the 1% that get the ol' rope caught in the prop.

I like Bonneville, but do not want to spend the future there and while underwater.
 
#24 ·
Armstrong, Sea Wolf, Wolf, Ironwood to name a few do not use an extended offshore bracket like a North River. The motor(s) are attached to the hull with the transom being recessed thereby losing deck space. So not everyone has bought into the extended hull offshore bracket.

Marketing is a wonderful thing. Take diamonds. Debeers would have you think that they are the most precious stone. Try to find a 5 carat ruby. Same can be said for boats imo. Just because a certain style is made doesn't mean it's the best thing out there. Best to try out the different styles and see what you like best.
 
#25 · (Edited)
Its not marketing. I had a Thunderjet with the "regular" style bracket. Nice boat but it would porpoise if you got a little aggressive with the trim. Older Tjets would get cracks so they beefed up the bracket. Northriver used to use the same bracket until they started cracking. I think Tacklebuster was one of the first to experience this. I believe Armstrong builds brackets for bigger, heavier boats which would better balance a heavy 4 stroke or 2 on the stern.
 
#27 ·
I have a 20 Boulton with a full height transom and a slop well. I like the way my boat handles with the motor attched to the boat's natural transom. I have never had an OS bracket, so I can't comment about that. I do know that running my kicker is easier with my slop well, and parking/storing it is a bit easier too. I also have a 12 degree bottom and won't be offshore a whole lot in it. Depends on the puropose, there's no right or wrong here.:twocents:
 
#28 ·
--I have much smaller boat than most with offshore bracket only 17.5' and 90hp 4 stroke 16 degree hull

--I use it for larger interior lakes that can get nasty.

--The benefit for me is hauling this boat around, smoother ride in chop trim down only lose a few MPH and excellent gas mileage as many of these larger lakes do not have gas facilities.

--weather permitting I use the bracket as a casting platform. I am closer to the water for fly fish or casting and use bow mount remote control electric.

--do a lot of trawling, some control issues in the wind as I have a high stand up canopy that acts like a sail.

--some backing up issues but have reduce the effect by extending leg of kicker and trimming up when backing up to get water push under the hull.. still a work in progress.

--the boat cost was a lot less than a 19 ft without offshore

--when on smaller lakes the size is not overwhelming to other fishers and I so far have been able to use rustic boat launches.
--the use of rustic boat launches was important conscideration as many of these lakes you have a choice to trailer and camp or long distance boat ride. Often the areas I launch in no way you could get a larger boat in and out of the water.

--Given the areas I like to fish the offshore bracket boat was a good option.
 
#32 ·
"for standard mono hulls a ratio of 12:1 boat length to engine set back is basically standard starting point.... beiing that for every foot of hull you want 1 " of distance from your hull to the front of the gearcase. and every 6 inches back from hull the cavitation plate of the engine can raise 1 inch up. so on a 22 ft boat you want 22" of distance from the end of the bottom to the front of the gearcase with the boat and engine level, and at 22" back the engine can go up 3.5" over baseline engine height without any ill effects of excessive height."


I am doing a re-power on a 21' 1989 Seaswirl Striper. Replacing an OMC I/O with a "Custom Made" offshore bracket and installing a 2010 225 Evinrude ETEC Model E225DPXISE.

What I am concerned with is how far back (how deep the bracket extension) the platform should be built, I am thinking between 26 and 30 inches and where should the cavitation plate line up with the motor trimmed all the way down? Some say even with keel (very bottom of boat?), some say raise mount height 1" for every 12" of bracket extension.

Anyone have any thoughts on this, I want to do the best I can here, only get one shot although I guess adjustments can be made after by raising or lowering via existing holes on mounting plate.

This is my first post here but have read quite allot this past week, awesome forum
 
#34 ·
I had an offshore bracket added on to my Hewes Searunner a few years ago by a great boat builder in Garibaldi. I haven't found one reason to regret the change and I continue to get positive comments from my family and fishing buddies.

Pros
More fishing room
Better ride
Safer in rough/following seas. I can fish in worse conditions more comfortably.
Swimstep earned big brownie points with wife, kids and even the dog who can just about get out of the water on his own.
A little quieter both trolling and under way with motors further back.
Better buoyancy
Easier to get grass and crap out of the propeller when away from the dock.
Built in hot water sink with kicker bracket

Cons
A little further to reach to start or tilt the kicker.
Took several adjustments to the single axle trailer to get the weight balanced while towing.

We haven't lost a fish yet due to issues with the motor further back and this is with multiple friends of my kids fighting there first, second and more salmon.
 
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