Boat weight question

[Stein]

Well, I just got some surprising news from the local Cat scale.  My 18' RH Seahawk came in at 3055 pounds on the trailer which is about 900 pounds heavier than I guesstimated and over the trailer rating.  The trailer is rated 2200# but I put 3220 pound rated tires (combined) and 3000 pound springs on it, I don't know what the axle is rated as it has no markings.

The manufacturer has the boat at 1230 dry, here is what I calculated:

Boat dry 1230
Mercury 90CT - 363
Yamaha 9.9  93
34 gallon main tank - full 204
Spare fuel (2.5 gallon) 15
Extra seats (2) (it came with 2 and I added the two back benches, I assume the front 2 are in the dry weight)  60
Two batteries 80 (assume they aren't in the dry weight)

Gear 100 (I took the downriggers, weights, rods, etc out so it just has life jackets, tools, flares, misc junk)

That puts the boat weight at 2145 which isn't close to 3055 - 910 pounds heavy.  I'm probably forgetting a thing or two but 900 is a bunch.

The scale also had the tongue weight at 700 exactly which is hugely heavy and 19.9% of the overall boat + trailer weight which isn't good either.  This is actually the reason I weighed it because it seemed a bit heavy and I was wondering if I should move the boat back a bit on the trailer.

Unfortunately, it's the only scale around my area so I can't get a second opinion but I would be surprised if it was off that much.  I was thinking of picking up a tongue weight scale and at least double checking that but I thought I would ask around here first to see if that weight sounds realistic and if anyone sees something I'm missing.

Unless I'm missing something I need to buy a 3500-3700 pound trailer as I'll load a couple hundred pounds of gear on the boat for combo shrimp/crab/fishing trips.

Weights from the scale with boat:

Steer 3240
Drive 2720
Trailer 2820
Gross 8780

Without boat

Steer 3120
Drive 2140
Trailer 0
Gross 5260

[Stein]

Well, I found one mistake.  For the re-weigh, I had to go in, pay for the first one and then he did the re-weigh when I was at the register, so I was in the truck for the boat weigh and not in the truck for the re-weigh.

That roughly puts tongue weight at 425 which is 13.1% and realistic and the on trailer weight of 2780 which is still 635 pounds heavy.  That still seems like a bunch of extra weight I can't account for.

[fishngamereaper]

You got foam under the deck... I've seen boat's add hundreds of lbs with water absorption in the floatation foam from the factory.

[huntnphool]

 Pull the floor boards and make the drain holes in the bracing bigger. I’m betting you have a floor full of water.

[RockChuck]

Maybe I missed it but did you add in the weight of the trailer in your calculations?

[Stein]

Maybe I missed it but did you add in the weight of the trailer in your calculations?

I did, subtracting that out the boat is 2780 and my calcs were 2145, so I'm still 635 heavy.

I could pull the middle section of floor which would only require removing 2 seats and then the floor, but even if I'm 50% wrong I'm 315 pounds heavy which is 38 gallons stuck somewhere.  It's only 3 years old and stored inside with the plug out, so I'm thinking it's highly unlikely that 38 gallons was absorbed in the floor.  There is space between the foam and hull and water can flow freely bow to stern in the bottom.

The easy button is to buy a 3700 pound trailer for $4,840 plus $254 for the swing tongue plus tax.   

[RockChuck]

I see it now 🤦🏻‍♂️😂

[fishngamereaper]

You would be surprised how much water that foam will hold...I pulled some year's ago and each hand full weighed a lb or two.  Probably took 300 lbs out of a 16.5 boat.

[Skillet]

Does the boat manufacturer's dry weight include the Mercury?  That 90 hp weighs 363#.

I know back when I was looking at boats like Hewescraft and Alumawels and such, they didn't include main in the dry weight, since you could rig it with any number of engine options.

[Dukalr]

I agree, 1230 lbs is WAY too much for that motor..... I’m pretty sure that’s where the miscalculation is.  I bet you’re fine weight wise for that trailer

[Stein]

Yeah, typo from my spreadsheet.  I had the numbers right there, just transposed them wrong here.

Boat is 1230 dry
90CT is 363 dry

Fat fingers, bad eyes and old age creeping up on me.

I sent an e-mail to the manufacturer to verify 1230 is the right number for my model year and to see if they have any insight.

I also read from a trailer guy that claims 90% of boats are overloading trailers, manufacturers skimp on the trailer because like me, not many people crawl under there to check the weight rating and then scale the boat before purchase.

I noticed there is a big gap between the common 3500 pound axles and the 6,000.  There are a few in the 4200 range, but not many and hard to source springs.

Anyone know a good trailer shop in the Everett to Mt Vernon area?  My current setup is bolted on the frame, so I could simply remove that and have someone weld me up a brand new suspension and axle.  I tried the one in Everett, but they actually wouldn't even talk to me when I drove in there last year.  Worst service I can remember. 

The other option is to run with what you brung.  I have several thousand miles on this one and it hasn't launched the boat out on the highway yet.

[huntnphool]

Maybe I missed it but did you add in the weight of the trailer in your calculations?

I did, subtracting that out the boat is 2780 and my calcs were 2145, so I'm still 635 heavy.

I could pull the middle section of floor which would only require removing 2 seats and then the floor, but even if I'm 50% wrong I'm 315 pounds heavy which is 38 gallons stuck somewhere.  It's only 3 years old and stored inside with the plug out, so I'm thinking it's highly unlikely that 38 gallons was absorbed in the floor.  There is space between the foam and hull and water can flow freely bow to stern in the bottom.

The easy button is to buy a 3700 pound trailer for $4,840 plus $254 for the swing tongue plus tax.   

 You may be surprised to find that much water in there, but this is coming from someone with a boat as well.

[Mfowl]

Check out Six Roblee's in S Everett. I replaced/upsized my trailer axle and springs through the Tukwila store several years ago when a spindle was damaged. They were great and knowledgeable to work with plus the price was very reasonable. I bought all the parts there and did the work at home in an afternoon. I did have to launch my boat and get it off the trailer to complete the work.

[Buzz2401]

I've known multiple people whose aluminum boat leaked like a sieve from that factory.  Two were North rivers.  Don't know anyone with a RH Seahawk but would not surprise me even a little if you had a small leak letting in water. 

[huntnphool]

I've known multiple people whose aluminum boat leaked like a sieve from that factory.  Two were North rivers.  Don't know anyone with a RH Seahawk but would not surprise me even a little if you had a small leak letting in water.

 NR boats are made with a one piece bottom and I’ve not seen a single issue among several friends that own them. What most people fail to think about is the amount of water used to wash the inside. If the drain holes get clogged, all that water sits in the hull, unseen, under the floor panels.