MONTAUK: Jack Plate, the Idea, the Benefit, the Drawback

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Author Topic:   MONTAUK: Jack Plate, the Idea, the Benefit, the Drawback

Moby Dick posted 10-02-2010 01:02 PM ET (US)
On a Montauk, what is the idea of a jack plate? What is the benefit of a jack plate? What is the drawback of a jack plate?
jharrell posted 10-03-2010 11:50 AM ET (US)
Benefits:
- Shallower running.
- Top speed increased.
Drawbacks:
- Being more careful with water pressure/water pickup.
- More weight on the back along with pushing motor weight further back.
- Possible interference with splash well with hydraulic steering.
I am probably going to do a CMC powered jackplate at some point because of how shallow I like to run. I just got a a Baystar hydraulic steering kit so I need to confirm the interference issue which was discussed here: http://continuouswave.com/ubb/Forum4/HTML/005732.html
Bobs Machine Jackplate is also appealing because of less weight on the transom, the downside being the hydraulic pump must be mounted somewhere in the boat, probably console, and hydraulic lines run there.
If you go manual everything is much simpler and lighter, but I really want the ability to adjust height while running.
Moby Dick posted 10-03-2010 04:20 PM ET (US)
Why does it result in shallower running? Can't you get the same affect by just mounting your motor up higher? Why faster? I was told the motor is suppose to be mounted to have the cavitation plate at the bottom of the keel at the stern.
contender posted 10-03-2010 07:33 PM ET (US)
jharrell: You will definitely need a power jack plate using the hydraulic steering. If you tilt the engine the cylinder will hit the splash well. You need to be able to raise the engine to tilt the engine all the way...
Moby: Fast=less drag, less lower unit in the water=less drag. The problem is the water pick up, to high the lower unit will not pick up water and over heat. They make special lower units for racing that have the water pick up moved to the bottom of the lower unit, also the lower unit housing is thinner(smaller dia.). You can mount your engine higher just do not go to high...
face posted 10-03-2010 08:07 PM ET (US)
Dead horse...use the search function on this forum!
jharrell posted 10-03-2010 09:11 PM ET (US)
Moby,
Shallower because:
1. you can mount on the bolt higher on the jackplate, then raise the Jackplate.
2. Jackplates usually raise higher than the bolts would on transom.
3. it sits further back the water has a chance to bulge back up off the transom, so you can go higher and still have the prop and water pickups in the water. That why some jackplates push the motor way off the back(12 inches or or more).
Faster because:
1. Less lower unit drag.
2. The further back the prop is off the transom the "cleaner" water it is in (less turbulence) which allows the prop to be more efficient.
dgoodhue posted 10-03-2010 10:01 PM ET (US)
I am running about 2.5" above the bottom of the hull with a 5" set back jackplate. I don't think their is no way I would be able to run my motor that high on the transom and still have my prop still grab.
Another advantage, is that you can fine tune the engine height. Atleast in my classic 15' 1/16" of an inch of engine hieght can be the difference on the top end from light controllable chine walk to having nearly out of control white knuckle chine walk.
jimh posted 10-03-2010 11:51 PM ET (US)
I don't know of anything about a MONTAUK which will affect the thinking behind installing a jack plate, the benefit of a jack plate, or the drawback of a jack plate. These all would be the same on a MONTAUK as on any other boat. A jack plate is a short set back bracket with adjustable vertical position. Please see an article in REFERNCE on the general topic of set back brackets:
http://continuouswave.com/whaler/reference/engineBrackets.html
Also, some examples of MONTAUK models with jack plates are found in
http://continuouswave.com/whaler/cetacea/cetaceaPage41.html
Sal DiMercurio posted 10-04-2010 10:53 AM ET (US)
Installing a jack plate will also help eliminate porpoising, & also smoother steering.
Both of my Whalers [ 15' Sport & 20' "V"20 Outrage ] have Bobs machine shop manual plates.
The plate improved performance in both hulls & really allowed me to control porpoising on my Outrage.
Between the jack plates, trim tabs, & tilt & trim, I can now fine tune the way both boats ride in any weather.
Sal
reidboat posted 12-11-2010 11:21 AM ET (US)
Sal or anyone else,
I saw your thread/comment about Whaler jackplates and porpoising.
> Installing a jack plate will also help eliminate porpoising, & also smoother steering.
> Both of my Whalers [ 15' Sport & 20' "V"20 Outrage ] have Bobs machine shop manual plates.
> The plate improved performance in both hulls & really allowed me to control porpoising on my Outrage.
> Between the jack plates, trim tabs, & tilt & trim, I can now fine tune the way both boats ride in any weather.
> Sal
As a 30+ year professional I am thoroughly looking into installing a jackplate on an old friend and customer's 17 Montauk with a 90 HP Merc. He likes to go to the Keys from here, but in Wilmington, NC jackplates are uncommon. Officially Whaler told us no jack plate. Causes porpoising, voids warranty, etc., in my opinion self serving legalize disclaimer and no help. I have installed only one jackplate before, as well as a pretty big Armstrong bracket on another boat with two new 225's, but am looking a Bob's Machine Shop hydraulic jack plate for this Montauk. I seem to like it better than the Stainless ones West Marine sells.
I know your models were 15' and 20' but you were so encouraging and confident that I thought it would be smart to ask you if you knew of any other Montauk 17 jack plate installations and their success. My main concern of course is porpoising and so my first question is;
1) You mentioned trim tabs also. Do you think they are a necessary addition to porpoising control?
2) Several forums have casually mentioned adding hydraulic steering with a jack plate. My question is why? I guess just because of the increased articulation? and likely alternative expense of buying a longer steering cable, even if it would stand the articulation? Or is hydraulic steering preferred for some other reason.
Other than you, or other undiscovered Whaler/ jack plate users, all that I can think of is asking Bob's Machine Shop for an end user referral. I'd very much appreciate any opinions, suggestions or leads you may have to offer.
thanks for your time,
Richard Reid
Wilmington, NC
www.reidboat.com
pcrussell50 posted 12-11-2010 02:30 PM ET (US)
Everybody likes as much speed as they can get, and from what I have been able to tell, in a year and a half here at CWW, Whaler people are no exception. Far from it, in fact as a good stainless prop and a hydraulic jacplate can set you back near as makes no difference to a thousand smackers, (before labor). And all for what? An extra couple of miles per hour? In a non-performance, utility-type hull, no less.
Then on the flipside, there is a nearly equal obsession with floating level in a static condition.
I find that to be an ironic dichotomy. How much level float are we willing to sacrifice to get an extra mph of speed? We can try to re-level the float by moving the battery and other weight forward, but doesn't that cost some speed?
What if we drop some serious coin on a jackplate and a heavy steel prop and through much trial and error, figure out how to unlock 2 mph? Next, we want our level float back, so we move batteries and fuel forward and give back one of our hard won, 2 mph? Is it all worth it in the end?
(Not a rhetorical question).
-Peter
Moby Dick posted 12-11-2010 05:16 PM ET (US)
I won't be putting a jackplate on my Montauk. With a 90 eTEC, it still should hit 40 mph which is much faster than normal water conditions allow.
jharrell posted 12-11-2010 06:30 PM ET (US)
Jack-plate's are not just for speed.
I am going to install one on my Monatauk in the coming year. I mainly want it for running in really skinny water up at the Chassahowitzka river, where at low tide there is less than 12" of water in much of the area. Just a few feet out of the "channel" and the prop is in the mud.
I have to run slow, off a plane, with the motor tilted up many times even though I know the river very well, mean while the locals up there all have jack plates and are flying past me.
The Montauk is a good hybrid boat that can go very shallow with only 9" of draft, a jack plate makes it even better.
jharrell posted 12-11-2010 06:37 PM ET (US)
Bob's jack plate has some advantages and disadvantages for a Montauk, if you are talking about the powered version.
The advantage is it is lighter than say a CMC, because the hydraulic pump is mounted elsewhere from the plate in a Montauk this would mean the console.
The disadvantage is the pump must be mounted somewhere, most likely in the console, complicating install and taking up precious console space.
I am probably going to do a CMC powered jack-plate, others here have installed them on Montauks with good results, and the weight difference is negligible compared to the pump install location IMO.
Bob's would be very convenient for me since they are local in Tampa and the do have a very good reputation.

L H G posted 12-11-2010 07:06 PM ET (US)
For salt water use, I highly recommend an anodized aluminum jackplate. Polished mill finish aluminum will quickly pit and corrode. Consider Detwiler, and the power unit is self contained.
Sal DiMercurio posted 12-12-2010 10:33 AM ET (US)
I really don't see any need for a hydraulic unit on your rig, as it only takes less than 5 minutes to adjust in manually.
Once it's at the optimum height, no need to adjust anymore.
If you were racing this rig, yes, but I don't see any advantage in going with the far more expensive unit for what you need.
Sal
jharrell posted 12-12-2010 10:46 AM ET (US)
I have never heard if corrosion being a problem with the CMC other than with the hydraulic pump which would still be a problem with the Detwiler. This is a muchh touted advantage of Bob's is having the pump aways from the water.
The Detwiler looks like a nice Jack-plate but is significantly heavier at 61 lbs vs 45 lbs for the CMC and 37 lbs for Bob's (only 29 lbs for Bob's in their "light" version for under 115HP).
Any opinion on why the Detwiler is so much heavier than the CMC?
The Montauk is more sensitive to weight than a larger whaler, that is why Bob's is very appealing, they sell lighter versions for lower HP and move the weight of the pump up front.
Tohsgib posted 12-12-2010 12:32 PM ET (US)
There really is no reason for a power plate. My Montauk was setup where the cav plate was about 4+" above the keel and she handled great, drew 4" less water and no need for a low water pickup, etc. Going higher(I did) made no improvement in speed, only more noise and a tad less draft. I say spend $175 for a nice manual plate and as Ron Popeil would say "SET IT & FORGET IT!"
towboater posted 12-15-2010 12:51 AM ET (US)
Check out CMC jack plates (poor man's offshore bracket) thru Cabelas. Around $250 last year. They are 5056 marine alum which is impervious to salt water...you dont need to powder coat it for another frigging $300. If it corrodes in your lifetime, just trash it and buy another one.
Sheesh.
I love the 4" for Merc 150, 18 ft Guardian. I agree with Jim, jackplates serve the same purpose for all boats.
More room in the spash well.
Steering and gear cables were relieved to need less angle.
Better turning, the boat seems to ride on the chine easier hard over because the setback brings the stern around easier.
Better steering in reverse, again, moving the rudder (pivot point) back 4" doesnt seem like a big deal but it helps in both directions.
Easier to remove/replace/dial in the engine.
I recomend aligning the anticavitation plate 1/2" above the keel for starters.
Lastly, go shopping for a NEW boat. I challenge you to find one that does not have some sort of offshore bracket or molded transom that "sets the engine back" compared to classic transoms. THere is a reason for this...the setbacks are proven better performance.
L H G posted 12-15-2010 07:16 PM ET (US)
....except in the case of the 1987-1990 Whaler Drive, where ride into a head sea is improved at the expense of top end speed and fuel economy.
Binkster posted 12-25-2010 03:56 PM ET (US)
Larry`s comment---For salt water use, I highly recommend an anodized aluminum jackplate. Polished mill finish aluminum will quickly pit and corrode. Consider Detwiler, and the power unit is self contained.
This is not neccessary if your boat lives on a trailer and always washed after use, when used in salt water. The aluminum will stay like new.
<"((>{
Binkster posted 12-30-2010 09:16 PM ET (US)
For the do-it-your-selfer, build your own for a few bucks.
http://www.dillon-racing.com/jackplate/index.htm
Good for up to 40hp.
I built a similar one for my 13 footer powered by a 25hp Merc/Tohatsu 4 stroke. It has a 6" setback, raised the cavitation plate 2 1/2" higher than the keel. Runs best with a 9" pitch cupped prop. Eliminated any porpoising, although I get some cavitation in a 2' following sea at speed. Runs 29-30mph GPS same speed as my 1958 35hp Evinrude Lark clamped to the transom. Yea, I know the old Lark is crankshaft hp rated.
<"))>{

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Author	Topic: MONTAUK: Jack Plate, the Idea, the Benefit, the Drawback
Moby Dick	posted 10-02-2010 01:02 PM ET (US) On a Montauk, what is the idea of a jack plate? What is the benefit of a jack plate? What is the drawback of a jack plate?
jharrell	posted 10-03-2010 11:50 AM ET (US) Benefits: - Shallower running. - Top speed increased. Drawbacks: - Being more careful with water pressure/water pickup. - More weight on the back along with pushing motor weight further back. - Possible interference with splash well with hydraulic steering. I am probably going to do a CMC powered jackplate at some point because of how shallow I like to run. I just got a a Baystar hydraulic steering kit so I need to confirm the interference issue which was discussed here: http://continuouswave.com/ubb/Forum4/HTML/005732.html Bobs Machine Jackplate is also appealing because of less weight on the transom, the downside being the hydraulic pump must be mounted somewhere in the boat, probably console, and hydraulic lines run there. If you go manual everything is much simpler and lighter, but I really want the ability to adjust height while running.
Moby Dick	posted 10-03-2010 04:20 PM ET (US) Why does it result in shallower running? Can't you get the same affect by just mounting your motor up higher? Why faster? I was told the motor is suppose to be mounted to have the cavitation plate at the bottom of the keel at the stern.
contender	posted 10-03-2010 07:33 PM ET (US) jharrell: You will definitely need a power jack plate using the hydraulic steering. If you tilt the engine the cylinder will hit the splash well. You need to be able to raise the engine to tilt the engine all the way... Moby: Fast=less drag, less lower unit in the water=less drag. The problem is the water pick up, to high the lower unit will not pick up water and over heat. They make special lower units for racing that have the water pick up moved to the bottom of the lower unit, also the lower unit housing is thinner(smaller dia.). You can mount your engine higher just do not go to high...
face	posted 10-03-2010 08:07 PM ET (US) Dead horse...use the search function on this forum!
jharrell	posted 10-03-2010 09:11 PM ET (US) Moby, Shallower because: 1. you can mount on the bolt higher on the jackplate, then raise the Jackplate. 2. Jackplates usually raise higher than the bolts would on transom. 3. it sits further back the water has a chance to bulge back up off the transom, so you can go higher and still have the prop and water pickups in the water. That why some jackplates push the motor way off the back(12 inches or or more). Faster because: 1. Less lower unit drag. 2. The further back the prop is off the transom the "cleaner" water it is in (less turbulence) which allows the prop to be more efficient.
dgoodhue	posted 10-03-2010 10:01 PM ET (US) I am running about 2.5" above the bottom of the hull with a 5" set back jackplate. I don't think their is no way I would be able to run my motor that high on the transom and still have my prop still grab. Another advantage, is that you can fine tune the engine height. Atleast in my classic 15' 1/16" of an inch of engine hieght can be the difference on the top end from light controllable chine walk to having nearly out of control white knuckle chine walk.
jimh	posted 10-03-2010 11:51 PM ET (US) I don't know of anything about a MONTAUK which will affect the thinking behind installing a jack plate, the benefit of a jack plate, or the drawback of a jack plate. These all would be the same on a MONTAUK as on any other boat. A jack plate is a short set back bracket with adjustable vertical position. Please see an article in REFERNCE on the general topic of set back brackets: http://continuouswave.com/whaler/reference/engineBrackets.html Also, some examples of MONTAUK models with jack plates are found in http://continuouswave.com/whaler/cetacea/cetaceaPage41.html
Sal DiMercurio	posted 10-04-2010 10:53 AM ET (US) Installing a jack plate will also help eliminate porpoising, & also smoother steering. Both of my Whalers [ 15' Sport & 20' "V"20 Outrage ] have Bobs machine shop manual plates. The plate improved performance in both hulls & really allowed me to control porpoising on my Outrage. Between the jack plates, trim tabs, & tilt & trim, I can now fine tune the way both boats ride in any weather. Sal
reidboat	posted 12-11-2010 11:21 AM ET (US) Sal or anyone else, I saw your thread/comment about Whaler jackplates and porpoising. > Installing a jack plate will also help eliminate porpoising, & also smoother steering. > Both of my Whalers [ 15' Sport & 20' "V"20 Outrage ] have Bobs machine shop manual plates. > The plate improved performance in both hulls & really allowed me to control porpoising on my Outrage. > Between the jack plates, trim tabs, & tilt & trim, I can now fine tune the way both boats ride in any weather. > Sal As a 30+ year professional I am thoroughly looking into installing a jackplate on an old friend and customer's 17 Montauk with a 90 HP Merc. He likes to go to the Keys from here, but in Wilmington, NC jackplates are uncommon. Officially Whaler told us no jack plate. Causes porpoising, voids warranty, etc., in my opinion self serving legalize disclaimer and no help. I have installed only one jackplate before, as well as a pretty big Armstrong bracket on another boat with two new 225's, but am looking a Bob's Machine Shop hydraulic jack plate for this Montauk. I seem to like it better than the Stainless ones West Marine sells. I know your models were 15' and 20' but you were so encouraging and confident that I thought it would be smart to ask you if you knew of any other Montauk 17 jack plate installations and their success. My main concern of course is porpoising and so my first question is; 1) You mentioned trim tabs also. Do you think they are a necessary addition to porpoising control? 2) Several forums have casually mentioned adding hydraulic steering with a jack plate. My question is why? I guess just because of the increased articulation? and likely alternative expense of buying a longer steering cable, even if it would stand the articulation? Or is hydraulic steering preferred for some other reason. Other than you, or other undiscovered Whaler/ jack plate users, all that I can think of is asking Bob's Machine Shop for an end user referral. I'd very much appreciate any opinions, suggestions or leads you may have to offer. thanks for your time, Richard Reid Wilmington, NC www.reidboat.com
pcrussell50	posted 12-11-2010 02:30 PM ET (US) Everybody likes as much speed as they can get, and from what I have been able to tell, in a year and a half here at CWW, Whaler people are no exception. Far from it, in fact as a good stainless prop and a hydraulic jacplate can set you back near as makes no difference to a thousand smackers, (before labor). And all for what? An extra couple of miles per hour? In a non-performance, utility-type hull, no less. Then on the flipside, there is a nearly equal obsession with floating level in a static condition. I find that to be an ironic dichotomy. How much level float are we willing to sacrifice to get an extra mph of speed? We can try to re-level the float by moving the battery and other weight forward, but doesn't that cost some speed? What if we drop some serious coin on a jackplate and a heavy steel prop and through much trial and error, figure out how to unlock 2 mph? Next, we want our level float back, so we move batteries and fuel forward and give back one of our hard won, 2 mph? Is it all worth it in the end? (Not a rhetorical question). -Peter
Moby Dick	posted 12-11-2010 05:16 PM ET (US) I won't be putting a jackplate on my Montauk. With a 90 eTEC, it still should hit 40 mph which is much faster than normal water conditions allow.
jharrell	posted 12-11-2010 06:30 PM ET (US) Jack-plate's are not just for speed. I am going to install one on my Monatauk in the coming year. I mainly want it for running in really skinny water up at the Chassahowitzka river, where at low tide there is less than 12" of water in much of the area. Just a few feet out of the "channel" and the prop is in the mud. I have to run slow, off a plane, with the motor tilted up many times even though I know the river very well, mean while the locals up there all have jack plates and are flying past me. The Montauk is a good hybrid boat that can go very shallow with only 9" of draft, a jack plate makes it even better.
jharrell	posted 12-11-2010 06:37 PM ET (US) Bob's jack plate has some advantages and disadvantages for a Montauk, if you are talking about the powered version. The advantage is it is lighter than say a CMC, because the hydraulic pump is mounted elsewhere from the plate in a Montauk this would mean the console. The disadvantage is the pump must be mounted somewhere, most likely in the console, complicating install and taking up precious console space. I am probably going to do a CMC powered jack-plate, others here have installed them on Montauks with good results, and the weight difference is negligible compared to the pump install location IMO. Bob's would be very convenient for me since they are local in Tampa and the do have a very good reputation.
L H G	posted 12-11-2010 07:06 PM ET (US) For salt water use, I highly recommend an anodized aluminum jackplate. Polished mill finish aluminum will quickly pit and corrode. Consider Detwiler, and the power unit is self contained.
Sal DiMercurio	posted 12-12-2010 10:33 AM ET (US) I really don't see any need for a hydraulic unit on your rig, as it only takes less than 5 minutes to adjust in manually. Once it's at the optimum height, no need to adjust anymore. If you were racing this rig, yes, but I don't see any advantage in going with the far more expensive unit for what you need. Sal
jharrell	posted 12-12-2010 10:46 AM ET (US) I have never heard if corrosion being a problem with the CMC other than with the hydraulic pump which would still be a problem with the Detwiler. This is a muchh touted advantage of Bob's is having the pump aways from the water. The Detwiler looks like a nice Jack-plate but is significantly heavier at 61 lbs vs 45 lbs for the CMC and 37 lbs for Bob's (only 29 lbs for Bob's in their "light" version for under 115HP). Any opinion on why the Detwiler is so much heavier than the CMC? The Montauk is more sensitive to weight than a larger whaler, that is why Bob's is very appealing, they sell lighter versions for lower HP and move the weight of the pump up front.
Tohsgib	posted 12-12-2010 12:32 PM ET (US) There really is no reason for a power plate. My Montauk was setup where the cav plate was about 4+" above the keel and she handled great, drew 4" less water and no need for a low water pickup, etc. Going higher(I did) made no improvement in speed, only more noise and a tad less draft. I say spend $175 for a nice manual plate and as Ron Popeil would say "SET IT & FORGET IT!"
towboater	posted 12-15-2010 12:51 AM ET (US) Check out CMC jack plates (poor man's offshore bracket) thru Cabelas. Around $250 last year. They are 5056 marine alum which is impervious to salt water...you dont need to powder coat it for another frigging $300. If it corrodes in your lifetime, just trash it and buy another one. Sheesh. I love the 4" for Merc 150, 18 ft Guardian. I agree with Jim, jackplates serve the same purpose for all boats. More room in the spash well. Steering and gear cables were relieved to need less angle. Better turning, the boat seems to ride on the chine easier hard over because the setback brings the stern around easier. Better steering in reverse, again, moving the rudder (pivot point) back 4" doesnt seem like a big deal but it helps in both directions. Easier to remove/replace/dial in the engine. I recomend aligning the anticavitation plate 1/2" above the keel for starters. Lastly, go shopping for a NEW boat. I challenge you to find one that does not have some sort of offshore bracket or molded transom that "sets the engine back" compared to classic transoms. THere is a reason for this...the setbacks are proven better performance.
L H G	posted 12-15-2010 07:16 PM ET (US) ....except in the case of the 1987-1990 Whaler Drive, where ride into a head sea is improved at the expense of top end speed and fuel economy.
Binkster	posted 12-25-2010 03:56 PM ET (US) Larry`s comment---For salt water use, I highly recommend an anodized aluminum jackplate. Polished mill finish aluminum will quickly pit and corrode. Consider Detwiler, and the power unit is self contained. This is not neccessary if your boat lives on a trailer and always washed after use, when used in salt water. The aluminum will stay like new. <"((>{
Binkster	posted 12-30-2010 09:16 PM ET (US) For the do-it-your-selfer, build your own for a few bucks. http://www.dillon-racing.com/jackplate/index.htm Good for up to 40hp. I built a similar one for my 13 footer powered by a 25hp Merc/Tohatsu 4 stroke. It has a 6" setback, raised the cavitation plate 2 1/2" higher than the keel. Runs best with a 9" pitch cupped prop. Eliminated any porpoising, although I get some cavitation in a 2' following sea at speed. Runs 29-30mph GPS same speed as my 1958 35hp Evinrude Lark clamped to the transom. Yea, I know the old Lark is crankshaft hp rated. <"))>{