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I'm looking into the possibility of adding a jack plate to my sport 15. This looks like it may be a good choice:

http://www.thmarine.com/products/Outboard-Jack-Plates/Hydraulic-Jack-Plates/ATLAS-hydraulic-jack-plates/Atlas-Micro-Jacker

Do any of you have any thoughts on what would be the best choice?

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http://www.thmarine.com/products/Outb...ck-plates/

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Why do you want to add a jack plate? What problem are you trying to solve?

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wlagarde,

I question the same thing.
The 15' models have a max hp rating of 70.
What are you trying to accomplish with your 40hp motor?

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Well I notice that when I trim the outboard way up I can get a max speed of 35mph (GPS). At that point of course I begin to get some porposing unless the water is really smooth. I thought I could use the jack plate to be able to on-the-fly adjust the height of the engine to optimize top end while maintaining the ability to independently adjust trim.

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I know I could just upgrade to a 70hp engine; however, I like idea of squeezing the most performance possible from this relatively light engine (~160 lbs) and also the fuel economy of a smaller engine.

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Mr Lagarde,
After having viewed your page,I think that I understand of your need to ad something to your Sport 15.
Your boat has obviously been well looked after and updated for some years now.
The viewed results from your personal page speaks volume about your care and attention for your favorite Whaler.
A jackplate could be possibly added to further your project but could be seen as not quite necessary for the style and model.
It may be time to look for another Whaler to start a brand new refit to occupy and have fun while doing it.

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Do you have a GPS? What RPM are you hitting at WOT? You might try just raising the engine and see if that helps?

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Right at 5600-5700 @ WOT. Because of the design of the transom I have limited ability to raise it. I suppose I could use a manual plate or build one? That would be cheaper and lighter.

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What hole is the motor mounted in now?

All the way up?
All the way down?

See this article and let un know where you motor is mounted.
http://www.whalercentral.com/articles...cle_id=106

A smaller motor does not guarantee better fuel economy.
A larger motor just loafing along can give better fuel economy and MUCH longer motor life.

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Thanks Joe - I added pictures to my personal page that detail the way the motor is mounted. It came to me mounted this way and I assume the previous owner used both upper bolt holes along with the motor clamps to mount the motor to avoid using the lower mounting holes since they would be below the transom well. It also appears the previous motor had a non-standard hole pattern (see pictures). Let me know your thoughts.

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Jack plates work great on 15'3" Sport hulls. They allow you to get the most out of your motor and reduce the porpoising. There is nothing standard about the Whaler sink bolt pattern. Some modifications need to be made to the Jack plate (drill extra holes). The micro jacker looks intriguing but I cannot tell if it would work with the extra holes. I use a T H Marine 4" Atlas model AHJ-4V-DP. I have also installed it on other 15'3" sports and it works great. It will improve the performance of your 40 and you can always still decide to upgrade to a 70 which it will also improve performance for.

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Ditto, 4" TH hydraulic Atlas Jacker is the sweetest on the market. I run it.

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I do like the idea of the on-the-fly ability to adjust engine height; however, I wonder if I could get near the same performance at a much lower cost by raising the engine 1 or 2 bolts if this can be done safely/properly. Can the lower bolt holes on the engine be utilized properly by installing blind end stainless lag screws? Would this be strong enough?

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To answer Joe's question directly the motor is mounted all the way down. The motor (NS40D2EPT02) has a shaft length 20" and the cavitation plate is just about even with the keel. I'm running a Solas New Saturn 12 pitch stainless prop.

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Reading a little further I think I could manufacture an adapter plate like suggested here: http://www.whalercentral.com/articles.php?cat_id=10&article_id=82. This would allow me to securely mount the motor using the original upper and lower holes through the transom.

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Many people just drill those Green holes and raise the motor to 2 holes up and do not use any kind of adapter or Jack Plate.
http://www.whalercentral.com/articles...icle_id=82

You would need to measure and layout those Green holes on both the inside and outside of the transom to make sure they will work for your motor.

Then you could mount any motor in the future as they all use the Standard Mounting hole pattern which works well.

There are several others here with personal pages describing how they drilled and use the Green holes.

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Thanks Joe - I guess the next thing I need to do is to raise the engine 1 hole and see what gain in performance I see. If I do (and I suspect I will) then I have confirmed that I will likely never want/need to mount an engine all the way down so going through the trouble of making the adapter plate is unnecessary. Fill the old lower holes with glass resin and drill the green holes and be done with it.

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Here is one members personal page.
Look at the last 4 photos.
http://www.whalercentral.com/infusion...ser_id=291

Again, layout and measure the holes on the inside and outside of the transom before drilling to make sure. You may have to bend or grind a flat spot on the inside washers to clear the inside splashwell.

Good Winter project.

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Great advise from Joe to be sure.
I have installed a first rate manual adjustment CMC Power Lift unit jackplate on my Classic Outrage 19 1975.
I am running a 25" leg and had to refer to the raising options given from the "PL" for my needs.
The addition of this plate will enable me to fine tune the height of my outboard and suit my needs.
For someone who want to invest a bit of time and money in order to fine tune speed and fuel consumption,
I would not hesitate to recommend this unit.
http://www.whalercentral.com/showuser...to_id=1644

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So Joe - Looking at the layout in detail, I'll need to raise the engine up 2 holes to be able to drill/use the green holes. Do you think that will be too much?

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Great advise from Joe to be sure.
I have installed a first rate manual adjustment CMC Power Lift unit jackplate on my Classic Outrage 19 1975.
I am running a 25" leg and had to refer to the raising options given from the "PL" for solutions.
The addition of this plate will enable me to fine tune the height of my outboard and suit my needs.
For someone who want to invest a bit of time and money in order to fine tune speed and fuel consumption,
I would not hesitate to recommend this unit.
http://www.whalercentral.com/showuser...to_id=1644

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wlagarde,

Almost all motors today, or motors with the newer props, can go 2 or 3 holes up, which would be all the way up for some motors.

The way I see yours now, you need to drill 2 holes no matter what.
Those 2 holes you have in the same upper bracket mount are going to need to be filled and never used again. Even if you use a jack plate, you do not want to use those 2 holes, so they need to be filled anyway.

Your very top 2 holes are probably OK if they are 1 7/8" to 2" down from the top of the transom.

I would raise the motor 2 holes by drilling the Green holes in the diagram if that works for your transom.
Then, you could always raise it another hole if you needed without drilling anymore holes even if you got a different motor as it would have a modified Standard BIA mounting pattern.

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OK - I'll start by testing performance with the motor raised 2 holes and see what happens. If all goes well I'll drill the green holes and fill the extra/unused holes.

ritzyrags and others - Thanks for the tips about jack plates. I may go for one of the manual ones...

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Joe - One final question: What is the best way/materials to use to fill the unused holes?

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Articles Section ----> Repair Articles ----> Filling Transom Holes

http://www.whalercentral.com/articles...icle_id=62

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Joe - The very top holes in my transom are 2" from the transom edge so they should be fine. I plugged the old holes (extra holes in the upper bracket mount and the lower black blind holes) and traced out the new lower green holes on my transom and it should work fine. I'll let you know how it goes.

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wlagarde,

Thanks for the info.
I didin't realize you still had the black blind holes as I couldn't really tell from the photos.

Take some photo of your project and keep us informed.
Always good to show other members how easy this may or may not be.

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Well after plugging the holes and sanding the transom down I exposed many old holes that have been plugged with epoxy (see pictures added to personal page). The quality of the previous repairs is good except that the holes are filled with epoxy resin flush with the surface of the gel coat. I still need to top off the holes I plugged with color-matched gel coat that I plan to order from Mini-Craft. The question is: Do I drill out (partially) the surface of the previously repaired holes so I can get some color-matched gel coat in place? I also plan to order an aerosol can of color-matched gel coat (also from Mini-Craft) and mask off and spray the exterior central transom section. I could also spray the interior of the transom well but that would be tricky if I wished to maintain the stencil (which I do). Any thoughts from the group?

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Thanks for the photos.

I see you haven't drilled the green holes yet but the motor mounted 2 holes up look good.

After you drill the lower holes, you won't need to use those engine clamps on the transom.

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OK I drilled the green holes and updated the photos.

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Excellent.

From the photos, I don't think you could have drilled the "Yellow" holes which are another 3/4 of an inch down.

Thanks for sharing and please keep those photos in your personal page or we can create a project album for you.

You might consider removing those upper clamp bolts as you no longer need them.

You can also raise your motor one more hole, if in the future, it would help for better performance, etc.

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Joe - The disks are riveted to the bolts. Should I just drill them out in order to remove the clamp bolts?

Also, once I have the gel coat done and and have finished the project let's create a project album.

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I decided to replace the transom drain tubes while repairing the transom. The seals for the old tubes were dry rotted and I was concerned about the possibility of water infiltration and I also wanted the tubes out while I spray the top coat of gelcoat. Well with great difficulty I was able to remove the two higher and short 3" transom well tubes. I noticed these were brass so I suspect they had been replaced previously, The lower long 15" tube that drains the bilge appears to be made of copper so I suspect it is original.

I am a little hesitant to try and remove the long tube since the short ones were so difficult; however, the seal is in such bad shape I feel compiled to replace it. Does anyone have any advice about the best way to remove the long transom tube on a sport 15. I have read the page about replacing tubes but there is no discussion about removing old tubes. Any help is appreciated.

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All Drain tubes were Brass.
http://www.whalercentral.com/photogal...hoto_id=54

Get it out however you can from one direction or the other.

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I changed mine to stainless through hulls, those brass tubes are the root of all evil for water infiltration into the hulls on these boats. After you remove the drain tubes, finish the inside of the holes with something to waterproof it. The holes on my black 15 are finished, and do not need the tubes. I'll see if I can get Eric to describe how the best way to do that was. I can try to muster up some pics, but did not want to take this thread off track. I think I mentioned before, the 4" hydraulic jacker from TH is perfect for these boats.

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Joe and James - Thank for the tips. It turned out the long tube was the easiest to remove. I cut the inside flange off with an oscillating saw and it tapped right out really easily - a big relief! I'm glad I removed it - the inside of the hole is a little moist but no rot thank goodness.

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James - Did you find it difficult to flare the stainless tubes? Where did you get the tubes? Also, I would love the details on waterproofing the holes. Did you use polyester resin? epoxy resin?

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It's simple enough. Oversize the holes and then patch them with a polyester based filler like adtech P-77 grind and glass both interior and exterior, gelcoat, sand, buff and redrill. now you have a water proof hole. As for the stainless they aare not knurled tubes they are stainless thruhull fittings that James had coupler made for.

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I sprayed the gelcoat - added pictures to personal page. Will wet sand, compound, polish, and wax tomorrow.

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those brass tubes are the root of all evil for water infiltration into the hulls on these boats

There is nothing wrong with using brass as through hull tubes on a BW Rockland, MA manufactured hull.

Original installation of brass tubes was done at BW Rockland, MA factory using only a rubber o-ring on each end of the brass tube. The o-ring deteriorated over a period of time; water then leaks into the tube area. If the brass tube seal is not repaired, water infiltration and damage to the wood core can result.

This is a basic maintenance issue on all BW hulls with brass drain tubes. It is perfectly fine to install new brass drain tubes; however, it is necessary to use a polysulfied caulk or equivalent sealer, or a technique like Eric described, when installing the new brass tubes.

It is nearly impossible for a DIY'er boat owner to flare stainless tubing. It is easy for a DIY'er BW owner to install brass through hull tubes, following the thoroughly documented techniques described by Mr. Tom Clark. A search on this site will reveal the instructions.

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Weatherly - In your opinion, Are 3M 4200 and/or 3M 5200 sealants an acceptable equivalent to polysulfide sealant?

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Yes. I have used both, but I prefer 4200 because it is easier to remove than 5200.

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Well I finished the job (pics added to personal page). Now the transom looks new and I have the motor mounted appropriately. The new brass tubes will be installed when they arrive this week. I must say spraying and finishing the gelcoat wasn't as bad as I thought it was going to be.

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Also, in case anyone is interested here are the details about the gelcoat work:

Once the transom was prepared, I cleaned the surface with acetone and sprayed 3 coats of Spectrum light grey Boston Whaler factory-matched gelcoat (http://www.spectrumcolor.com/ProductD...amp;key=it) using a Preval sprayer (http://shop.preval.com/collections/pr...al-sprayer). All coats were thinned 10% with acetone. The first two coats were sprayed without surfacing agent and the final coat with Spectrum-provided surfacing agent added. I allowed the gelcoat to cure 1hr between coats and 24hrs before final sanding/polishing. I sanded out the orange peel with 220 wet and then moved up through 400, 800, 1000 wet followed by compound and then wax.

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Looks great.

Good job on the transom and raising the motor using the Green holes.

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Thanks for the compliment Joe - I installed the thru-hull drain tubes (updated personal page with photos). A little tricky if you try to use the flaring tool with the bolt provided. I made a modified air chisel/flaring tool like Tom Clark describes http://www.whalercentral.com/articles...icle_id=42 and it worked like a charm.

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The photos for this project have been relocated to a project album: http://www.whalercentral.com/userphot...lbum_id=64

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I raised my engine up another hole (all the way up). In this position it aerates a little as it rises onto the plane (trimmed in neutral position) and I don't see any additional performance increase so I lowered it back to the 2 holes up position.

Tom/Joe - Do you think this is related to the Solas New Saturn prop I have installed or is it just that optimal for my setup is 2 holes up?

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Different propeller have different tolerances of motor mounting heights. I am not a fan of Solas propellers. I'd try a different propeller and see how it does.

What was the measured boat speed at the different mounting heights?

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Down 1 hole its just tipping between 38 and 39mph on GPS w/ rpm @ 5700.

All the way up gets 39 solidly and rpm is slightly higher.

Gear ratio is 1.85. Prop is solas new saturn stainless 14p

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That's pretty damn good.

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OK as long as you think I'm optimized I'll leave it be.

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Well, that depends on what "optimized" means to you?

You might be able to find a prop/motor height that is faster, if that is what you want.

You might find a prop/motor height that offers better acceleration, if that is what you want.

If you're happy with what you have, I'd leave it be.

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SO if I were to optimize around speed which propeller would you recommend?

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10-1/2" x 13" Stiletto Triad or Turbo Hot Shot

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Thanks Tom - I'll try this out.

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The engine is mounted to the transom, right? 39mph out a 50hp/classic 15' is excellent. For reference, I would expect to see 40mph out of a 60hp/15' I am just not sure how much more speed your going to see with a prop change. You might like the new prop better for grip or acceleration. I know that I like my stiletto better than my OMC SST even though they had the same top speed, cruise speed. The stiletto just seem to have more grip.

If you want additional top speed, I would spend it on a jack plate. I think you would be lucky to get 1mph with a new prop. The jack plate should be worth 3mph with the right prop. (You might need a new prop though for the jackplate, it would probably push your rpm up another 400rpm.)

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Yes I agree but for me its just not worth the $1000.

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jack plate won't get you any attributable benefit except porpoising. You have hit the wall of performance, the only thing left to do is modify the hull. I can assure you I am the most experienced with the 15' hull and mods. Extending the strakes to the transom will transform your hull into a faster more stable machine. You are just a bit under powered to really be concerned with one or two mph. At this point you would be best served to get a bigger motor, a sweet used 70 or 90 Yamaha 2-stroke. And if that's not enough i know plenty of mods for the motor to take you to 50+ safely.

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Yes I think I'm doing very good with the 50. My goal was to optimize what I had and I think I've done that. I am happy with it and I'll sit tight for now.

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Lastly thank you to everyone for your help.

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Claiming to be the most experience with the 15' hull is a pretty big claim. I have a stock hull and my boat only goes 47-48mph, but I do have a little bit experience with my 15' whaler and playing around with the engine, props, jack plate and engine height.

The 5" setback manual Jack plate on my 15' does not porpoise w/ 260# 3 cylinder OMC I know quite a few other 15' whaler owners with jack plates and none of them have porpoising. (60 & 70hp motors) Maybe your hull mods have an affect on jack plate mounting or perhaps the engine weight of an overpowered motor is causing the porpoising with a jack plate. Its a pretty big claim to say it doesn't have attributable benefit. I have been reading the couple whaler forums for 10 years, every 15' Classic whaler I have seen do a GPS measure 46-48mph has been with a jackplate. Most 70's do 42-44mph mounted on the transom.

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It doesn't, we've done five now and ran them with various motor configurations of Yamaha 70 and 90 HP two-strokes and four-strokes and Merc 90 two strokes and a Mer T.O.P. 115 some with jack plates some with out. If I am repeating myself too much I apologize in advance, but the classic 15 hull is a skiff with potential for tinkering, and the inherent limits of the hull are not hydrodynamic, they are aerodynamic. My aspirations were above normal, and just like anyone exploring the limits, we found all of the little details that make the system work better in general. Extending the strakes has an all around positive effect, that even make the hull more efficient at lower speeds. When I studied the mods, the wet running surface area was reduced from stock configuration by more almost 50%, which was dramatic in the boats behavior, speed, and efficiency.

I have jack plates on all of my small skiffs, and honestly would not recommend them for a small boat like this unless you troll rivers, flats, or shallows. They do have a tendency to cause porpoising and are not worth the marginal gain. I would say a 50# jack plate would have better results putting in in the front locker as a ballast, than it does on the transom of a 15. I should know, I've tried it.