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R I Whaler posted 09-27-2006 08:08 PM ET (US)
Just bought a kicker on ebay listed as long shaft. I shared a picture of it with a member here and he thinks it is a short shaft. What is the precise way to measure to be sure. I am going to have the seller measure before I pay him.
Thanks,
Mike
Binkie posted 09-27-2006 08:31 PM ET (US)
Picture the outboard bolted on a transom. You would measure from the top of the transom to the cavitation plate. A short shaft should be around 15", a long shaft should be 20", and an extra long shaft should be around 25".For some reason these measurements are not exact, maybe plus or minus an inch, or so.
R I Whaler posted 09-27-2006 08:52 PM ET (US)
Thanks Binkie. Just so I'm sure, the cav. plate is the horizontal fin plate directly above the prop? And you measure exactly at where the top of the transome would be? What is that part, or point, called on the motor? I'm going to have to explain this to the seller in order to get an accurate measurement.
Mike
Tonym posted 09-27-2006 09:21 PM ET (US)
Mike,
If you get the seller to provide you with the serial # you can check it on the internet. Generally it will start with a series of letters that you can cross reference as to shaft length, tiller, electric start or manual etc. Tonym
R I Whaler posted 09-27-2006 09:48 PM ET (US)
TonyM,
The seller states Model# E10RSLM Serial# 0194576
Can you tell anything from this? How would I check on internet?
I know the E= Evinrude, 10= 10 hp, SL= year(I think)
That's all I've been able to get from internet. Any help would be appreciated.
I have a good picture of the motor I could e-mail to anyone that might be able to take a guess. The Judge thinks pretty surely its a short based on the picture.
Thanks,
Mike
Binkie posted 09-27-2006 10:35 PM ET (US)
measure from Cavitation plate to top of Bracket.
Tom W Clark posted 09-27-2006 10:55 PM ET (US)
No, not from the czvitation plate, but somewhere above it. Most small OMC motors will measure approximately 17-1/2" from cavitation plate to apex of bracket clamps if they are 15" ("short")shafts and 22-1/2" for long shafts.
st posted 09-27-2006 11:03 PM ET (US)
R I,
When I was shopping for my kicker at Ebay, I found out that a lot of sellers did not regard this shaft lenght to be that important-especially those that act as the agents. (But as we-the Whalers know, how critical this can be). Sometimes they don't know what that meant, and other times they would just gave you the answer you're looking for. So, it is very prudent in your part to be sure the shaft lenght you're buying is correct for your transom.
Our friends Binkie gave you a good general idea how to measure it, and Tonym gave you alternate solution on determing the right lenght using internet data base somewhere, hope you can find it.
If I may refine further of Binkie's definition; this is how I would tell the seller to do:
Please, measure the distance between:
a. The lower surface portion of the motor's transom bracket to:
b. The "anti cavitation" plate (yes, it's the plate directly above the prop).
Note, I purposely use the word "the lower surface portion"; if the seller were to measure the top portion, the difference would be the thickness of the bracket, which could be about 2 inches.
By the way, I would also consider "our" Judge's guess to be
highly valueble-due to his vast experience. Let us know what's the conclusion of your effort!
Sam
Bjornas posted 09-27-2006 11:33 PM ET (US)
What year does he claim the motor to be? There are different translation charts for different years.
Chuck Tribolet posted 09-27-2006 11:56 PM ET (US)
http://www.brokeboats.com/omcid.html sez
E - Evinrude
10 - 10 HP
RS - Rope Start
L - Long (20") Shaft
M - ??

Chuck
The Judge posted 09-28-2006 11:21 AM ET (US)
Chuck you are not even close. This engine is nOT a US engine. These are commercial engines that were export only I believe. My buddy has the same engine. If this was a long shaft it would have a shaft extension which it does not. I also know it is short because we have used it on a jon boat.
Imbedded in the model number is the Make, horsepower and year of the engine.
For example:
If your model number is E200TLCOS your engine is a 1985 200hp evinrude engine.
The first Letter corresponds to the first letter of the make of your engine.
The next numbers are the engine hp.
The second to last two letters correspond to the year listed in the chart below.
1980(CS) 1981(CI) 1982(CN) 1983(CT) 1984(CR) 1985(CO)
1986(CD) 1987(CU) 1988(CC) 1989(CE) 1990(ES) 1991(EI)
1992(EN) 1993(ET) 1994(ER) 1995(EO) 1996(ED) 1997(EU)
1998(EC) 1999(EE) 2000(SS) 2001(SI)
Chuck Tribolet posted 09-28-2006 12:58 PM ET (US)
Judge: Let's parse the model number by your info:
E - Evenrude
10 - 10 HP
SL - year, but not right
M - ??
That doesn't work any better. Something is fishy with that
model number.
The key to deciphering the OMC year is the word INTRODUCES
I - 1
N - 2
T - 3
R - 4
O - 5
D - 6
U - 7
C - 8
E - 9
S - 0
No L.
My engine is an E90ELEUA
E - Evinrude
90 - 90 HP
E - Electric start
L - 20" transom
EU = '97
A - Batch A
That fits my engine.
Chuck
The Judge posted 09-28-2006 01:26 PM ET (US)
I know it does not work. Neither does my buddy's # which is 1 letter short. These are NOT US engines and I believe are export only. They have the 9.9 engine but have an older 25hp style midsection with a small foot and no thru-hub. Let him send you a pic, looks like a Frankenstein engine designed from some 1970's OMC parts bin. The foot actually has 2 fins on each side as well, never seen that before. No matter what it is...she is a short shaft and that is his problem.
pglein posted 09-28-2006 02:26 PM ET (US)
Just ask him to measure the distance from the cavitation plate to the underside of the top of the transom bracket (where the engine would rest on the top of the transom). If he's too stupid to figure that out, then you don't want to do business with him anyway.
Plain and simple.
tgresla posted 09-28-2006 03:35 PM ET (US)
I am waiting for someone to say shaft lenghth is measured from the top of the ba#$s to the tip
R I Whaler posted 09-28-2006 05:55 PM ET (US)
Here is an update. First, thanks to everyone helping me out. You all have saved me from potentially buying a motor that wont work. Especially The Judge.
Here is what the seller has confirmed: Model# is E10RSLM
Serial # 0194576.
He has given two measurements: (1) From "bottom of motor housing to center line of prop" is 25 inches. (2) From transom line (with motor mounted tight to the transom) to the cavitation plate is 18.5 inches.
He also stated that the plate states "Made in Hong Kong"
I have pictures I can mail to anyone who wants to look at this creature. It is a good looking motor. The seller is happy to negate the deal. He seems genuinely concerned.
pglein posted 09-28-2006 06:18 PM ET (US)
Sounds to me like a 20" shaft.
st posted 09-28-2006 06:43 PM ET (US)

quote:
From transom line (with motor mounted tight to the transom) to the cavitation plate is 18.5 inches
From Tom's description, looks like it's about 4" short of a Long shaft.
Chuck Tribolet posted 09-28-2006 07:57 PM ET (US)
Far eastern knock-off?

Chuck
Binkie posted 09-28-2006 08:28 PM ET (US)
Tom W Clark is right about 17 1/2" between the cav. plate and the top of the bracket for short shaft motors. I have a 7 1/2 hp Merc and a 75hp McCulloch, both `60`s vintage that measure 17 1/2". The transom measurement for a 13` Whaler made for short shaft motors is 16 3/4". What I`d like to know is where the 15" comes into play? Who would know the answer to this?
R I Whaler posted 09-28-2006 09:15 PM ET (US)
It doesn't seem that we have a consensus. Most are leaning towards short shaft, but why is this one a bit longer at 18.5" ? pglein thinks it's a long. Hey, Judge, did I understand your last post to mean that you friend's motor, which you originally thought was a long shaft, is, upon review, the same short shaft?
Any thoughts on the made in "Hong Kong"?
Again, I appreciate everyone's advise. Hope I can reciprocate some day.
Mike
Tom W Clark posted 09-28-2006 11:41 PM ET (US)
Oh brother. You guys are making this far more complicated than it needs to be.
Mike bought a short shaft motor on Ebay which will not work on his Outrage 20 without modifying it.
Shaft length simply refers to the size of transom it is designed to mount on. It is not measured from the cavitation plate, which is designed to be under water on small motors.
The original 13 foot Whaler has a 15" transom, not a 16-3/4" transom. Transom height is just that, [b]height[/], not "distance along the surface of." The 13's transom slants back quite a bit. Go measure it. For you geometric types: the hypotenuse of a triangle is greater than its altitude.
OMC had a factory in Hong Kong, hence the "Made in..." The model number reported above does not comport with any US market OMC model number sequence. This also fits with the "Made in Hong Kong" report as well as Nick's observation. It would also suggests the motor is a LATE 1990s not an early 1990s model.
R I Whaler posted 09-29-2006 06:18 AM ET (US)
Thanks for clearing that all up. I have just cancelled the transaction with the seller. No hard feelings. I will search locally for a kicker.
The Judge posted 09-29-2006 12:37 PM ET (US)
Thanks Tom....keep us posted on your findings RI Whaler.
R I Whaler posted 10-05-2006 05:50 PM ET (US)
My kicker isssue is resolved. I cancelled the ebay sale of the Evinrude Super 10. I just bought, locally, a beautiful 1996 Johnson 15 hp long shaft, manual everything. The motor is mint, weighs 70 lbs and is exactly what I was hoping for. Thank you, everyone, for helping me out.
Mike
devildog posted 10-05-2006 09:40 PM ET (US)
Top 5 Answers to the Original Question:
1. With a friend
2. Always from the underside
3. Just prior to optimum performance level
4. If you have to ask...
5. Is that a gun in your pocket?
Hey! Wait a minute! What's this? Some sort of boating site?
Binkie posted 10-06-2006 08:34 AM ET (US)
On a 13 foot Whaler does anyone know what the angle of the transom is in relation to the bottom. I believe this would have to be obtained from plans, as due to the complex hooked bottom, laying a straightedge along the bottom you will come up with different angle measurements according to the length of your straightedge. If you know the angle of the transom, and the length of the transom (16 3/4") simple geometry will tell you what the height of the transom is, probably around 15 inches. No one has as yet explained why short shaft motors irregardless of hp, measure about 17 1/2" from cavitation plate to top of bracket. Long shaft motors are about 22 1/2". It is common knowledge that the cav. plate should be at least even with the bottom and most times higher than the bottom on planing hulls, and most motors need to be shimmed, or the bracket top raised above the transom to run their best.
Rich
Tom W Clark posted 10-06-2006 09:07 AM ET (US)
Rich,
The 13 footer's transom angles back about 20 degrees. The height of its transom has almost become a frequently asked question:
http://continuouswave.com/ubb/Forum3/HTML/003129.html
http://continuouswave.com/ubb/Forum1/HTML/011884.html
http://continuouswave.com/ubb/Forum4/HTML/000509.html
No, small outboards are NOT deigned to have their AV plates even with the bottom of the boat. The AV plate is to be BELOW the bottom of the hull. That is why they are necessarily more than 15" (or 20 " in the case of a long shaft) below the top of the clamp brackets.
Read your small outboard's owner's manual for more information.
Binkie posted 10-06-2006 01:30 PM ET (US)
Well, I have a short shaft 75hp outboard that measures 17 1/2" and my 15hp Suzuki which is a 20" shaft I think measures 22 1/2" but I will measure to be sure.
Steve Leone posted 10-07-2006 09:52 PM ET (US)
Judge, I can relate to your description of that finned beast that looks like a 1970`s throwback. I think it was only produced for a year or two. It probably inspired those god awful plastic doel fins / hydro-stabilizers. I have encountered more bad lower mounts and stressed out transoms from the use of those things. I lost count on how many I have thrown in the trash.
Bjornas posted 10-08-2006 01:04 AM ET (US)
My Tohatsu 40 HP shortshaft manual explicitly states:
1) Install the engine with the anti-ventialtion plate at a level 10mm-30mm below the bottom of the boat.
2) Be sure that the anti-ventialtion plate of the outboard is below the water surface when running wide open throttle.
3)In case the above condition cannot be met, please consult your dealer
4) Overheating may occur if the anti-ventilation plate is at a level higher than the bottom of the boat, as a result of air sucking.
5)If the height difference exceeds 10mm-30mm engine power performance is likely to be reduced as a result of increased water resistance to the gear case assembly.

jgkmmoore posted 06-23-2007 06:20 PM ET (US)
Shaft lengths, most outboards:
Description: Actual measured length-
Anti-cav plate to transom top
Short 15".......... 17-18"
Long 20".......... 22-24"
Xtra-Long 25"...... 27-28.5"
XXL 30".......... 32-34
The actual measured length will be longer than the 'described' length (to account for the transom angle).
When the motor is mounted on the boat and trimmed properly, the anti cav plate should ride flush with the boat bottom.
Binkie posted 06-23-2007 08:23 PM ET (US)
jgk,
your post says it all. It should be recorded somewhere on this website for posterity.
BUT in some cases raising the cavitation plate above the bottom of the boat, and even clear of the water will increase performance.
This can only happen if the motor has enough HP in relation to the size, weight and bottom shape, of the boat to swing a higher pitch prop and will still have bite even though it is running near the surface. If you think raising the motor will increase performance in all cases try it on an underpowered or a heavily laden boat with maximum recommended power If you put a 40hp motor on a 15 ft. Whaler, and jack it up to where the cavitation plate is running clear of the water, you will lose performance. Put a 90 on the same boat and you can gain performance with the same setup, so transom height is not written in stone. That's why race boats spend so much time testing. I believe that's why manufactures made the statement that jgk more or less quoted.
They can`t go wrong with that setup,
Rich
Tom W Clark posted 06-24-2007 10:46 AM ET (US)
Jeff,
Your ranges are a bit to specific; its not quite that neat. It depends on what size and brand motor you are talking about.
My Mercury 150 LONG shaft motors measure 20" from AV plate to mounting bracket. The shorter height is typical of Mercury outboards.
jgkmmoore posted 06-24-2007 06:32 PM ET (US)
Tom- Please note the operational word in the first sentence, 'most'. I wrote this thing so folks know that the 'GENERAL practice' of manufacturers is to quote shaft lengths that are LESS than actual measured lengths, rather than MORE than measured lengths.
jgkmmoore posted 06-24-2007 06:41 PM ET (US)
When I hit the 'submit' button, my paragraph got rearranged, which changed the meanings. 'Description' was typed to be over the first part of each sentence to show the manufacturers description. 'Actual measured' was supposed to be typed over the second part of each sentence. Hope most folks got the idea. It's a general statement, to be used only as a guideline.
Tom W Clark posted 06-24-2007 06:52 PM ET (US)
Jeff,
Since Mercurys ar ethebiggest selling outboards, I suppose you really meant to say "some", eh?
So there you have it, shaft lengths are all over the place...in general.

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Author	Topic: how is shaft lenght measured
R I Whaler	posted 09-27-2006 08:08 PM ET (US) Just bought a kicker on ebay listed as long shaft. I shared a picture of it with a member here and he thinks it is a short shaft. What is the precise way to measure to be sure. I am going to have the seller measure before I pay him. Thanks, Mike
Binkie	posted 09-27-2006 08:31 PM ET (US) Picture the outboard bolted on a transom. You would measure from the top of the transom to the cavitation plate. A short shaft should be around 15", a long shaft should be 20", and an extra long shaft should be around 25".For some reason these measurements are not exact, maybe plus or minus an inch, or so.
R I Whaler	posted 09-27-2006 08:52 PM ET (US) Thanks Binkie. Just so I'm sure, the cav. plate is the horizontal fin plate directly above the prop? And you measure exactly at where the top of the transome would be? What is that part, or point, called on the motor? I'm going to have to explain this to the seller in order to get an accurate measurement. Mike
Tonym	posted 09-27-2006 09:21 PM ET (US) Mike, If you get the seller to provide you with the serial # you can check it on the internet. Generally it will start with a series of letters that you can cross reference as to shaft length, tiller, electric start or manual etc. Tonym
R I Whaler	posted 09-27-2006 09:48 PM ET (US) TonyM, The seller states Model# E10RSLM Serial# 0194576 Can you tell anything from this? How would I check on internet? I know the E= Evinrude, 10= 10 hp, SL= year(I think) That's all I've been able to get from internet. Any help would be appreciated. I have a good picture of the motor I could e-mail to anyone that might be able to take a guess. The Judge thinks pretty surely its a short based on the picture. Thanks, Mike
Binkie	posted 09-27-2006 10:35 PM ET (US) measure from Cavitation plate to top of Bracket.
Tom W Clark	posted 09-27-2006 10:55 PM ET (US) No, not from the czvitation plate, but somewhere above it. Most small OMC motors will measure approximately 17-1/2" from cavitation plate to apex of bracket clamps if they are 15" ("short")shafts and 22-1/2" for long shafts.
st	posted 09-27-2006 11:03 PM ET (US) R I, When I was shopping for my kicker at Ebay, I found out that a lot of sellers did not regard this shaft lenght to be that important-especially those that act as the agents. (But as we-the Whalers know, how critical this can be). Sometimes they don't know what that meant, and other times they would just gave you the answer you're looking for. So, it is very prudent in your part to be sure the shaft lenght you're buying is correct for your transom. Our friends Binkie gave you a good general idea how to measure it, and Tonym gave you alternate solution on determing the right lenght using internet data base somewhere, hope you can find it. If I may refine further of Binkie's definition; this is how I would tell the seller to do: Please, measure the distance between: a. The lower surface portion of the motor's transom bracket to: b. The "anti cavitation" plate (yes, it's the plate directly above the prop). Note, I purposely use the word "the lower surface portion"; if the seller were to measure the top portion, the difference would be the thickness of the bracket, which could be about 2 inches. By the way, I would also consider "our" Judge's guess to be highly valueble-due to his vast experience. Let us know what's the conclusion of your effort! Sam
Bjornas	posted 09-27-2006 11:33 PM ET (US) What year does he claim the motor to be? There are different translation charts for different years.
Chuck Tribolet	posted 09-27-2006 11:56 PM ET (US) http://www.brokeboats.com/omcid.html sez E - Evinrude 10 - 10 HP RS - Rope Start L - Long (20") Shaft M - ?? Chuck
The Judge	posted 09-28-2006 11:21 AM ET (US) Chuck you are not even close. This engine is nOT a US engine. These are commercial engines that were export only I believe. My buddy has the same engine. If this was a long shaft it would have a shaft extension which it does not. I also know it is short because we have used it on a jon boat. Imbedded in the model number is the Make, horsepower and year of the engine. For example: If your model number is E200TLCOS your engine is a 1985 200hp evinrude engine. The first Letter corresponds to the first letter of the make of your engine. The next numbers are the engine hp. The second to last two letters correspond to the year listed in the chart below. 1980(CS) 1981(CI) 1982(CN) 1983(CT) 1984(CR) 1985(CO) 1986(CD) 1987(CU) 1988(CC) 1989(CE) 1990(ES) 1991(EI) 1992(EN) 1993(ET) 1994(ER) 1995(EO) 1996(ED) 1997(EU) 1998(EC) 1999(EE) 2000(SS) 2001(SI)
Chuck Tribolet	posted 09-28-2006 12:58 PM ET (US) Judge: Let's parse the model number by your info: E - Evenrude 10 - 10 HP SL - year, but not right M - ?? That doesn't work any better. Something is fishy with that model number. The key to deciphering the OMC year is the word INTRODUCES I - 1 N - 2 T - 3 R - 4 O - 5 D - 6 U - 7 C - 8 E - 9 S - 0 No L. My engine is an E90ELEUA E - Evinrude 90 - 90 HP E - Electric start L - 20" transom EU = '97 A - Batch A That fits my engine. Chuck
The Judge	posted 09-28-2006 01:26 PM ET (US) I know it does not work. Neither does my buddy's # which is 1 letter short. These are NOT US engines and I believe are export only. They have the 9.9 engine but have an older 25hp style midsection with a small foot and no thru-hub. Let him send you a pic, looks like a Frankenstein engine designed from some 1970's OMC parts bin. The foot actually has 2 fins on each side as well, never seen that before. No matter what it is...she is a short shaft and that is his problem.
pglein	posted 09-28-2006 02:26 PM ET (US) Just ask him to measure the distance from the cavitation plate to the underside of the top of the transom bracket (where the engine would rest on the top of the transom). If he's too stupid to figure that out, then you don't want to do business with him anyway. Plain and simple.
tgresla	posted 09-28-2006 03:35 PM ET (US) I am waiting for someone to say shaft lenghth is measured from the top of the ba#$s to the tip
R I Whaler	posted 09-28-2006 05:55 PM ET (US) Here is an update. First, thanks to everyone helping me out. You all have saved me from potentially buying a motor that wont work. Especially The Judge. Here is what the seller has confirmed: Model# is E10RSLM Serial # 0194576. He has given two measurements: (1) From "bottom of motor housing to center line of prop" is 25 inches. (2) From transom line (with motor mounted tight to the transom) to the cavitation plate is 18.5 inches. He also stated that the plate states "Made in Hong Kong" I have pictures I can mail to anyone who wants to look at this creature. It is a good looking motor. The seller is happy to negate the deal. He seems genuinely concerned.
pglein	posted 09-28-2006 06:18 PM ET (US) Sounds to me like a 20" shaft.
st	posted 09-28-2006 06:43 PM ET (US) quote: From transom line (with motor mounted tight to the transom) to the cavitation plate is 18.5 inches From Tom's description, looks like it's about 4" short of a Long shaft.
Chuck Tribolet	posted 09-28-2006 07:57 PM ET (US) Far eastern knock-off? Chuck
Binkie	posted 09-28-2006 08:28 PM ET (US) Tom W Clark is right about 17 1/2" between the cav. plate and the top of the bracket for short shaft motors. I have a 7 1/2 hp Merc and a 75hp McCulloch, both `60`s vintage that measure 17 1/2". The transom measurement for a 13` Whaler made for short shaft motors is 16 3/4". What I`d like to know is where the 15" comes into play? Who would know the answer to this?
R I Whaler	posted 09-28-2006 09:15 PM ET (US) It doesn't seem that we have a consensus. Most are leaning towards short shaft, but why is this one a bit longer at 18.5" ? pglein thinks it's a long. Hey, Judge, did I understand your last post to mean that you friend's motor, which you originally thought was a long shaft, is, upon review, the same short shaft? Any thoughts on the made in "Hong Kong"? Again, I appreciate everyone's advise. Hope I can reciprocate some day. Mike
Tom W Clark	posted 09-28-2006 11:41 PM ET (US) Oh brother. You guys are making this far more complicated than it needs to be. Mike bought a short shaft motor on Ebay which will not work on his Outrage 20 without modifying it. Shaft length simply refers to the size of transom it is designed to mount on. It is not measured from the cavitation plate, which is designed to be under water on small motors. The original 13 foot Whaler has a 15" transom, not a 16-3/4" transom. Transom height is just that, [b]height[/], not "distance along the surface of." The 13's transom slants back quite a bit. Go measure it. For you geometric types: the hypotenuse of a triangle is greater than its altitude. OMC had a factory in Hong Kong, hence the "Made in..." The model number reported above does not comport with any US market OMC model number sequence. This also fits with the "Made in Hong Kong" report as well as Nick's observation. It would also suggests the motor is a LATE 1990s not an early 1990s model.
R I Whaler	posted 09-29-2006 06:18 AM ET (US) Thanks for clearing that all up. I have just cancelled the transaction with the seller. No hard feelings. I will search locally for a kicker.
The Judge	posted 09-29-2006 12:37 PM ET (US) Thanks Tom....keep us posted on your findings RI Whaler.
R I Whaler	posted 10-05-2006 05:50 PM ET (US) My kicker isssue is resolved. I cancelled the ebay sale of the Evinrude Super 10. I just bought, locally, a beautiful 1996 Johnson 15 hp long shaft, manual everything. The motor is mint, weighs 70 lbs and is exactly what I was hoping for. Thank you, everyone, for helping me out. Mike
devildog	posted 10-05-2006 09:40 PM ET (US) Top 5 Answers to the Original Question: 1. With a friend 2. Always from the underside 3. Just prior to optimum performance level 4. If you have to ask... 5. Is that a gun in your pocket? Hey! Wait a minute! What's this? Some sort of boating site?
Binkie	posted 10-06-2006 08:34 AM ET (US) On a 13 foot Whaler does anyone know what the angle of the transom is in relation to the bottom. I believe this would have to be obtained from plans, as due to the complex hooked bottom, laying a straightedge along the bottom you will come up with different angle measurements according to the length of your straightedge. If you know the angle of the transom, and the length of the transom (16 3/4") simple geometry will tell you what the height of the transom is, probably around 15 inches. No one has as yet explained why short shaft motors irregardless of hp, measure about 17 1/2" from cavitation plate to top of bracket. Long shaft motors are about 22 1/2". It is common knowledge that the cav. plate should be at least even with the bottom and most times higher than the bottom on planing hulls, and most motors need to be shimmed, or the bracket top raised above the transom to run their best. Rich
Tom W Clark	posted 10-06-2006 09:07 AM ET (US) Rich, The 13 footer's transom angles back about 20 degrees. The height of its transom has almost become a frequently asked question: http://continuouswave.com/ubb/Forum3/HTML/003129.html http://continuouswave.com/ubb/Forum1/HTML/011884.html http://continuouswave.com/ubb/Forum4/HTML/000509.html No, small outboards are NOT deigned to have their AV plates even with the bottom of the boat. The AV plate is to be BELOW the bottom of the hull. That is why they are necessarily more than 15" (or 20 " in the case of a long shaft) below the top of the clamp brackets. Read your small outboard's owner's manual for more information.
Binkie	posted 10-06-2006 01:30 PM ET (US) Well, I have a short shaft 75hp outboard that measures 17 1/2" and my 15hp Suzuki which is a 20" shaft I think measures 22 1/2" but I will measure to be sure.
Steve Leone	posted 10-07-2006 09:52 PM ET (US) Judge, I can relate to your description of that finned beast that looks like a 1970`s throwback. I think it was only produced for a year or two. It probably inspired those god awful plastic doel fins / hydro-stabilizers. I have encountered more bad lower mounts and stressed out transoms from the use of those things. I lost count on how many I have thrown in the trash.
Bjornas	posted 10-08-2006 01:04 AM ET (US) My Tohatsu 40 HP shortshaft manual explicitly states: 1) Install the engine with the anti-ventialtion plate at a level 10mm-30mm below the bottom of the boat. 2) Be sure that the anti-ventialtion plate of the outboard is below the water surface when running wide open throttle. 3)In case the above condition cannot be met, please consult your dealer 4) Overheating may occur if the anti-ventilation plate is at a level higher than the bottom of the boat, as a result of air sucking. 5)If the height difference exceeds 10mm-30mm engine power performance is likely to be reduced as a result of increased water resistance to the gear case assembly.
jgkmmoore	posted 06-23-2007 06:20 PM ET (US) Shaft lengths, most outboards: Description: Actual measured length- Anti-cav plate to transom top Short 15".......... 17-18" Long 20".......... 22-24" Xtra-Long 25"...... 27-28.5" XXL 30".......... 32-34 The actual measured length will be longer than the 'described' length (to account for the transom angle). When the motor is mounted on the boat and trimmed properly, the anti cav plate should ride flush with the boat bottom.
Binkie	posted 06-23-2007 08:23 PM ET (US) jgk, your post says it all. It should be recorded somewhere on this website for posterity. BUT in some cases raising the cavitation plate above the bottom of the boat, and even clear of the water will increase performance. This can only happen if the motor has enough HP in relation to the size, weight and bottom shape, of the boat to swing a higher pitch prop and will still have bite even though it is running near the surface. If you think raising the motor will increase performance in all cases try it on an underpowered or a heavily laden boat with maximum recommended power If you put a 40hp motor on a 15 ft. Whaler, and jack it up to where the cavitation plate is running clear of the water, you will lose performance. Put a 90 on the same boat and you can gain performance with the same setup, so transom height is not written in stone. That's why race boats spend so much time testing. I believe that's why manufactures made the statement that jgk more or less quoted. They can`t go wrong with that setup, Rich
Tom W Clark	posted 06-24-2007 10:46 AM ET (US) Jeff, Your ranges are a bit to specific; its not quite that neat. It depends on what size and brand motor you are talking about. My Mercury 150 LONG shaft motors measure 20" from AV plate to mounting bracket. The shorter height is typical of Mercury outboards.
jgkmmoore	posted 06-24-2007 06:32 PM ET (US) Tom- Please note the operational word in the first sentence, 'most'. I wrote this thing so folks know that the 'GENERAL practice' of manufacturers is to quote shaft lengths that are LESS than actual measured lengths, rather than MORE than measured lengths.
jgkmmoore	posted 06-24-2007 06:41 PM ET (US) When I hit the 'submit' button, my paragraph got rearranged, which changed the meanings. 'Description' was typed to be over the first part of each sentence to show the manufacturers description. 'Actual measured' was supposed to be typed over the second part of each sentence. Hope most folks got the idea. It's a general statement, to be used only as a guideline.
Tom W Clark	posted 06-24-2007 06:52 PM ET (US) Jeff, Since Mercurys ar ethebiggest selling outboards, I suppose you really meant to say "some", eh? So there you have it, shaft lengths are all over the place...in general.