Outboard Motor Test Tanks: Design & Construction

[Captin Hazlewood]

How about one of these?

[Instigator]

Was actually thinking of that.

Matt, on the water oscillation due to the prop, it’s way reduced w/a test wheel but is still there.
Even w/boat on trailer at ramp.
I will say, it 99% better than trying to do it w/a regular prop.

My WFO hits are short and more checking tuning to get to that point.
Bogs, misses, timing etc.

How about one of these?

[Chaz]

Test wheels have an issue that most forget, they create no forward thrust that the design of the case/bearings need

Sure they do, just not enough to empty the swimming pool ...



And I have one of each .. L. and R. Which will grab a 300 horse motor and stall it @ 6000 rpm . If you gotz a real ~ real healthy one .. 6400



And approved by the Mothership ...



Swimmin pools, big tanks, holes in the ground ...

Just back it down in the water, break it in under a load, adjust timing and A/F ratio ... trim down and let it eat @ the poor mans dyno ...

For builds with no boat, I was thinking about an old trailer with a platform and a transom to mount the motor on. battery, gauges, wire and cables ..

[Instigator]

Love it!

W/o a boat, I was thinking mount it to bed of truck.
Back in, crawl in bed and tune away.

I like your LH.
Great idea.
I haven’t tried my real one on a LH yet but bet it works.
I know there is s part number for a LH though.

Sure they do, just not enough to empty the swimming pool ...



And I have one of each .. L. and R. Which will grab a 300 horse motor and stall it @ 6000 rpm . If you gotz a real ~ real healthy one .. 6400



And approved by the Mothership ...



Swimmin pools, big tanks, holes in the ground ...

Just back it down in the water, break it in under a load, adjust timing and A/F ratio ... trim down and let it eat @ the poor mans dyno ...

For builds with no boat, I was thinking about an old trailer with a platform and a transom to mount the motor on. battery, gauges, wire and cables ..

[Instigator]

Ah, gotcha.

Thats what I’d have if I had Robs money.

Double R- Outfit N. of the border here in Canuckistan dug a small pond and back boats in ramp on trailer!

[Instigator]

Matt, look at Chaz’s picture then recalculate the size you’ll need 😂

[MattGreen]

Was actually thinking of that.

Matt, on the water oscillation due to the prop, it’s way reduced w/a test wheel but is still there.
Even w/boat on trailer at ramp.
I will say, it 99% better than trying to do it w/a regular prop.

My WFO hits are short and more checking tuning to get to that point.
Bogs, misses, timing etc.

Oh yeah, totally agree, the test wheel is better but not perfect. I've done V4s and V6s with test wheels in a tank and it isn't what I'd call "stable" WFO operation. Loud as hell too - another design consideration to cover down the road.

I also totally agree with Chaz and Gary that taking the boat to the ramp is the best approach. For a variety of logistical reasons that is not practical for me here in Calgary. When I used to live in Ontario near the St. Clair river, I would tow to a quiet, free county-owed ramp outside of town - worked great, but not viable here.

Matt

[Instigator]

Even if the ramp is 5 mins away it’s still a PIA.

In Fla I was 10 mins from one but was busy so had to plan accordingly.

Still not at your shop, your schedule etc.

I want it behind my shop.

My baby tractor, w/a backhoe, might make a big enough hole but not sure.

Oh yeah, totally agree, the test wheel is better but not perfect. I've done V4s and V6s with test wheels in a tank and it isn't what I'd call "stable" WFO operation. Loud as hell too - another design consideration to cover down the road.

I also totally agree with Chaz and Gary that taking the boat to the ramp is the best approach. For a variety of logistical reasons that is not practical for me here in Calgary. When I used to live in Ontario near the St. Clair river, I would tow to a quiet, free county-owed ramp outside of town - worked great, but not viable here.

Matt

[MattGreen]

OK, good input above, thanks everybody. Let’s cover commercially available tanks.

Kerr Speciality Tool in Florida has been around a long time and makes several different models of test tanks: http://www.kerrsmarine.com/products-2. They are up-front about the horsepower ratings for their different models, which gives some insight into tank volumes needed for different sized engines. Shop-fabricated tanks I have seen and used all seemed similar to the Kerr tanks, so would I be off-base to say these would be “OB dealership industry standard” ?

Kerr’s main competitor seems to be Specialty Motors out in Washington, who also make a whole range of tanks: https://www.specialtymotorsmfg.com/outboard-test-tanks . They make a number of models which are round, and have really cool integrated air-hydraulic motor hoists. As part of my research on tank design, I called the owner (a very helpful woman named Sharon), who gave me a number of insights. She has a ton of experience in the OB/marine industry. Their round tanks are used for factory testing by Mercury, to 350 hp and beyond, and Cal-EPA has also used their tanks for emission testing on the biggest Yamahas. So again, I think their water volume-versus-horsepower ratings can be used to help with tank design. If I could afford it I think I’d buy one of these, they seem top-notch. The round shape should reduce a lot of the unstable operation issues discussed above. I have never used a round test tank before. Does anybody have any experience to share on how well they work – with a regular prop or a test wheel ?

As a price comparison to building my own, Specialiy’s largest tank (i.e. steel, rated for the power I want to test), which comes standard with the air/hydraulic lift, is $10K US funds. With shipping, taxes, and exchange to our dollar, that’s well in excess of $15k. My goal is to build an equivalent fiberglass tank (minus the hoist) for less than 1/10^th of that.

Matt

[Chaz]

If you dig a big pit in the back yard .. ya better be buildin a cement pond , or the wifey is gonna think ya lost the other oar ...



Test wheels don't ocellate the the RPM graph ... trying to run a 300+ horse motor in a soup can is the culprit.

See the wood slats on each side of the dock that the county put in for me. They are really high tech .. vortex de-generators .. Notice how smooth the water is leaving the slats and filling under the boat as compared to the condition of the water leaving the circulation pumps ... (Tropical Smoothie{-=

Monday thru Thursday at 10 am is a good time to be alone at the ramp.
4 pm till sundown is a great time for other's to be there doing the same thing. Always brings out a crowd of neighbors, taters (spec type) and "helpers" ..

If ya don't live a couple hunertt yards from the ramp .. ya still gotta go however far to go boatin .. it's the same distance to get your **** in one pile ..

[PanRonnie]

OK, good input above, thanks everybody. Let’s cover commercially available tanks.

Kerr Speciality Tool in Florida has been around a long time and makes several different models of test tanks: http://www.kerrsmarine.com/products-2. They are up-front about the horsepower ratings for their different models, which gives some insight into tank volumes needed for different sized engines. Shop-fabricated tanks I have seen and used all seemed similar to the Kerr tanks, so would I be off-base to say these would be “OB dealership industry standard” ?

Kerr’s main competitor seems to be Specialty Motors out in Washington, who also make a whole range of tanks: https://www.specialtymotorsmfg.com/outboard-test-tanks . They make a number of models which are round, and have really cool integrated air-hydraulic motor hoists. As part of my research on tank design, I called the owner (a very helpful woman named Sharon), who gave me a number of insights. She has a ton of experience in the OB/marine industry. Their round tanks are used for factory testing by Mercury, to 350 hp and beyond, and Cal-EPA has also used their tanks for emission testing on the biggest Yamahas. So again, I think their water volume-versus-horsepower ratings can be used to help with tank design. If I could afford it I think I’d buy one of these, they seem top-notch. The round shape should reduce a lot of the unstable operation issues discussed above. I have never used a round test tank before. Does anybody have any experience to share on how well they work – with a regular prop or a test wheel ?

As a price comparison to building my own, Specialiy’s largest tank (i.e. steel, rated for the power I want to test), which comes standard with the air/hydraulic lift, is $10K US funds. With shipping, taxes, and exchange to our dollar, that’s well in excess of $15k. My goal is to build an equivalent fiberglass tank (minus the hoist) for less than 1/10^th of that.

Matt

10 to 15K!
My airplane ticket is going to be a lot cheaper
But if you are not afraid of getting your hands dirty
https://www.grainger.ca/en/product/T...TH/p/MLW907710

[PanRonnie]

the good thing about saving some money is that you can buy a test wheel that can turn both clockwise and counterclockwise!

[Chaz]

the good thing about saving some money is that you can buy a test wheel that can turn both clockwise and counterclockwise!

Saving money ...

I open the lid and pour money in the top. The wifey has a hole at the bottom where she drains it back out ...

[PanRonnie]

You should weld that hole shut!

[Chaz]

I've tried that, but she crosses her legs and .....