Transom height above ground when on trailer

[.Mike]

My boat's transom is over 27 inches off the ground when it is on the trailer. I'm pretty sure that is too high, and I bet it makes launching my boat more difficult than it needs to be.

Is there a recommended distance between the transom and ground when a boat is sitting on the trailer?

After reading the sticker on my trailer, it seems that someone replaced the 8-inch tires with 12-inch tires somewhere along the way. The current tires are almost 22 inches in diameter. I plan on putting on some 8-inch tires, which are 16.1 inches. That should drop the transom by about 3 inches, which will help. It's only 3 miles to the boat ramp, so I am not too concerned about flats or bearings.

 

[CedarRiverScooter]

I would leave the wheels alone. 12 inch tires are good.

There are other ways to drop the bunk height.

One way is to mount the axle so it is on top of springs.

Another really easy thing is to mount your hitch ball with the receiver bar flipped up.

How about some photos of your trailer?

 

[.Mike]

My situation is a bit tricky, since I tow with a car. I don't have a lot of tongue height. I have explored all options to raise the height of the hitch ball, and short of a new vehicle, there is really nothing out there. I plan on getting a truck, but a car is what I have to work with for now.

Luckily, the boat ramp is 3.0 miles and 4 turns away, top speed 45MPH. If I go out every weekend for a year, that's only 300 miles. I will not be towing the boat to any other ramp until after I get a truck.





The tongue and main support of the trailer are 2"x3" square tubing. At the axle, from the bottom of the tube to the ground is 16 inches. At the hitch, when I hook it up to my car, measuring from the the bottom of the tube, it is only 12 inches. There is a 4 inch drop from axle to hitch that makes me uncomfortable. That is one of the main reasons I want to lower the back half of the trailer, and not just how the boat sits on the trailer.

The trailer seems too short to me, so I eventually will bolt on a longer tongue to move everything forward. It definitely came with 8-inch wheels when this boat/motor/trailer package was new. It looks like the fenders were removed to make way for the larger tires. I would like fenders to avoid spraying my boat with sand on the way home. Also, fenders with a step would allow my 5 foot tall wife to reach into the boat to help load and unload, instead of just watching me do it!

If I were to flip the axle to the top of the springs, the larger tires would be really close to the bottom of the boat. It is a really wide boat, and there isn't much clearance.

That is why I think 8-inch wheels are ideal in my situation. For now, it seems wisest to improve the tongue angle and lower the boat a few inches. 8-inch tires do that with with 10 bolts, 10 minutes, and $100.

My trailer does have rollers. They work really well, although they also add height. The saltwater is eating them fast, so they'll need to be replaced in the next year. I will likely be able to lower the boat by about two inches when I switch to bunks, if necessary. The boat sits parallel to the main trailer support.

With smaller tires, I might even be able to flip the axle. That would make the trailer level, and put the transom about 21 or 22 inches above the ground. That's why I am wondering if there is an acceptable range, or a minimum clearance. If everyone's boat sits 18 inches above the ground, and mine is 27 inches, I want to know!

 

[lckstckn2smknbrls]

You want your skeg to be high enough that it clears the ground when towing. Whether you tow with the motor down or motor up with a transom saver.

 

[richg99]

My boat is hauled with a Toyota Sienna Van. The van's gas tank is mounted across the back, so the hitch is lower than it should be. Picture the ball mount below flipped upside down. Something similar, matching your height needs, may help you out.



https://www.etrailer.com/Ball-Mounts/Convert-A-Ball/AMSC12.html

 

[Weldorthemagnificent]

I have 8” wheels on my trailer. They made me nervous at first because they turn faster than larger wheels and I didn’t want to be that guy on the side of the hwy shaking his head. However, I have made several 5 hour trips with this rig and everything is good. I check for heat at every stop and it’s always ok. Either get some bearing buddies or repack your bearings every season and you’ll be fine. Especially the distance you are going. Be sure to check the weight of your rig and make sure it falls well under the tire load rating. Keep a check on tire pressure. Happy fishing!


Sent from my iPhone using Tapatalk

 

[.Mike]

Thanks guys! So I gather that 27 inches between the transom and ground isn't necessarily bad. But, also that I can go as low as I want, within reason, provided I have enough clearance for the motor.

Unfortunately, my hitch is a light duty 1-1/4" class I. I originally bought it for my bike rack. There aren't many accessories for it. I found a ball that gives 2" rise, but it won't fit in my ball mount without modification. This is what I have now, and I haven't found anything that will fit that gives me more height: https://www.amazon.com/CURT-45024-Class-Ball-Mount/dp/B003AT49X2/

The trailer came with bearing buddies, so I'm set there. I'm sure I will be fine on weight, too. 230lbs boat, 85lbs motor, 6 gallons of fuel, a trolling motor, and a couple of seats. It can't be more than 850lbs. All the load range B tires I've seen support around 600lbs each, and I'll never be over 1,000lbs.

I plan on getting a transom saver. The motor bounced around the first time I towed it, so I have resorted to bungee cords to keep it stationary.

Thanks again. I'm going to order some tires and see what kind of difference it makes.

 

[richg99]

Looks like you are going down a checklist of things that you can do to make her launch better.

As already suggested, putting the axle on top of the springs will add a few inches. Sometimes, you can lower the bunk supports, too.

Incidentally, rollers are not recommended for tin boats, though your boat is pretty light and it may not be a factor.

If you plan on replacing the rusty roller brackets anyhow, that might be another thing that you can do at this time to get her lower. A longer tongue or a tongue extension can help a lot.

The little 1 1/4 inch hitch might have to be traded out so that you can get the other things that you might need to launch without swamping your vehicle. I know, since I did that one time.

 

[w2much]

My Klamath also sits high above the ground. I like it that way. It allows to tow with the motor in the down position . The down position on a tin boat is preferable to me as I do not need a transom saver. Even if I wanted a transom saver one would be difficult to attach to the trailer due to the configuration of the trailer rear crossmember. Ever tow or watch another person tow a tinny with the motor in the tilt position.? Watch how that motor bounces either in your rear view mirror or on the road. I have worked on numerous tin boats and have had to weld or reinforce the transoms. I used to think it was the weight or thrust of the motor until I looked in my rear view mirror. These boats are light enough, just may need to give it a bit of a shove off or tug onto the trailer when launching and retrieving.
As mentioned make certain that your lower unit skeg has plenty of ground clearance even when you travel over a sharp road transition such as a rather sudden uphill from a flat road, like your steep driveway or baja travels.

 

[RaisedByWolves]

Something to think about if you launch from a beach or a short ramp.


The smaller tires will sink into the sand or gravel and make for a more difficult retrieval. Also they can get hung up easier if you back the trailer off of a short ramp or at low tide.

Im thinking OP's trailer was not ment for that boat and the fenders were removed to fit the flat bottom on it.

As an aside, my transom will be 34" off the ground with a 14' v hull. :lol:

 

[.Mike]

I am positive that this was all sold originally as a package, although that is 25 years and several owners in the past. The sticker on the trailer says 8" tires.



Someone put 12" tires on it, which is almost certainly why the fenders were removed. There would be plenty of clearance between the boat and tires if I flipped to the top of the leaf spring with 8" tires, but with 12" tires, it is too close for comfort.

The guy I bought it from had a huge truck. It seems reasonable to me that he put on taller tires to get more appropriate trailer height and angle. That is exactly what I am trying to do. Easier launching will be a nice bonus.

There is nothing I can do about my hitch. It is the beefiest one sold for my vehicle. A truck is still a year or two off for me. Same for the rollers. They sure look original to me. Either way, I will be replacing them with bunks in the next year or so. I doubt one more year of use will do any damage, considering there is no damage from the past 25 years (thankfully). I will be able to extend the tongue by about 16 inches with a few holes, a few bolts, and about $60 in galvanized steel. All in the works, eventually. Baby steps are better on my bank account.

This is where I launch, shown at fairly low tide. https://binged.it/2yDwfOy At the 0.00 low tides, that bay has only 6 inches of water. On the negative lows, it is a mud pit. Bing needs to reimage-- there are two sunken boats next to the ramp, and a shipwreck across the bay, that aren't in that image. It's a good ramp, but the parking lot is like the surface of the moon.

 

[PGRChaplain]

Mike, i had the same problem. Switched to 8" tires helped a lot. My trailor had been redone to accommodate a much larger Boat. It's a 1967 Gator trailor, the same model I had 45 years ago that carried a Crosby Fibreglass 16' with a 75 HP Johnson. I drug that old boat everywhere and never had any problems with the 8" Tires.

 

[JL8Jeff]

That doesn't look like the right size trailer for that boat. The boat should fit between the tires/fenders which should get it lower. That roller setup does not look original to the trailer either and sits kind of high. I have a Lowe 1652 with a roller trailer and my transom is 23" off the ground which is still a little high and that's with the 12" tires. If I switched to bunks, I have room to lower it 3-6" if I wanted to but my boat stays in the water most of the season so I don't trailer it that often and the cost to switch to bunks doesn't make sense. One other thing to think about when going back to 8" tires, since they spin faster and will generate more heat around the bearings, you should wait a little longer for them to cool down before backing it into the water. Heat is what will allow the water to get sucked in around the bearings so extra cooling time may prevent premature bearing failure. The correct trailer is the right solution, especially when you start to take longer trips but that is obviously an increased cost.

 

[.Mike]

I really think it is the right trailer. It was all bought as a package from one dealer back in the early 90s. The boat is a 14 footer. The trailer model number is 14700C-- almost certainly indicating for a 14 footer. I'm getting it into shape, and things are starting to fit better.

I put on 8" tires-- like it says right on the trailer's sticker-- and it makes a huge difference. The old 12 inch tires were 22" in diameter. The new ones are 16.1". That lowers the trailer by 3", which is a big difference. Still over 7 inches of clearance between the bottom of the skeg and the ground. I can now see vehicles behind me. My wife can reach into the boat without a step stool. I can jack my tongue high enough to drain water out of the boat without a cinder block.

I haven't been able to get the boat in the water yet to test, though. We had 20 mph winds all last weekend, and now we have company in town for Thanksgiving for the next 5 days. But without even launching the boat, the improvements are already worth it.

Regarding the increased revolutions of the tire, I did the math for my situation. The recommendations for 12 inch tires simply do not apply. It is exactly 3 miles to the boat ramp, 45mph speed limit. My tires turn 3,758 times on the way to the boat ramp, vs 2750 with the old tires. I go the speed limit, never exceeding 45 mph, so that is about 940 RPM with 8 inch tires. 12 inch tires turn faster then that at 65mph, about 993 RPM. Mathematically speaking 8 inch tires spin slower at my top speed of 45 mph than 12 inch tires spin for anyone who hauls over 60 mph. So while I appreciate the repeated warnings and recommendations, the math just doesn't prove it out.

 

[JL8Jeff]

Yeah, you should be fine with the lower mph short trips. It's the longer highway speed trips that could lead to problems. What's the model # on the trailer? That should tell you what it's designed for. It really looks like a PWC trailer that someone added boat rollers to and moved the winch mount forward which is why there isn't much tongue left.

 

[RiverBottomOutdoors]

I don't really think you have a problem. Looks normal to me. You could extend the trailer tongue to get the boat further down the ramp during launch.