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Jet ski/Boat trailer attachment

Printed From: CorrectCraftFan.com
Category: General Correct Craft Discussion
Forum Name: General Discussion
Forum Discription: Anything Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=47877
Printed Date: September-16-2024 at 12:34am


Topic: Jet ski/Boat trailer attachment
Posted By: mbshaw88
Subject: Jet ski/Boat trailer attachment
Date Posted: August-06-2019 at 2:00pm
Going on a boating trip in WI next week and want to bring both my 82SN and also my 87 Kawasaki Stand up. Unfortunately my buddy sold his pickup which I used last year by putting the ski in the truck bed and towing the trailer. So I came up with a design to haul both using my 2010 4Runner

Specs:
Vehicle Towing limits: 5000lb/ 500lb Tongue Weight (TW)
Boat Estimated weight: 2600lb
Boat with trailer estimated weight: 3550lb
Estimated jet ski weight: 250 lb

I wanted a removable trailer attachment that would allow me to tow the boat & ski:
1. Without going over my total tow capacity
2. Without exceeding my TW capacity
3. While maintaining 8-15% TW/total weight distribution
4. With the ability to still tow the boat without the ski installed

I borrowed a 600lb scale from work to measure my current TW (375lb), and from that measurement and estimated boat/trailer weight I could estimate the boat center of gravity (CG) distance from the axle.

I would need to extend the tongue to make room for the jet ski, but also room to turn my vehicle, and open the hatch.

Putting the jet ski on the front of the trailer (375lb +250lb) would overload my TW capacity, so I would need to shift the boat rearward by moving the bowstop. The combination of extending the tongue and shifting the boat rearward would give me some sweet spot to meet my criteria.

- Shifting the boat too far rearward might be fine for towing with the jet ski, but if it's not on the trailer when I'm only towing the boat, my TW distribution could be well below a stable %
- Shifting the boat to little rearward and I could get very close or even exceed my TW limit when the jet ski is installed

Using the variables of tongue extension length and new bow stop distance I was able to determine:
- Moving the boat back 2" is ~25lb off the TW
- Extending the tongue every 6" is ~10 lbs of the TW

I decided on a max extension of 26" and moving the bow stop back 7". With this setup I estimate jet ski loaded TW to be about 450lb (>10%) and my unloaded TW distribution with the extension all the way in, to be about 7.5%.

The jet ski will be ratchet strapped to the supports and I'm going to remeasure the TW once everything is installed.

Skids made from carpeted 2x4's
Supports made from welded 3/16" Steel plates (CNC plasma cutter)
Extension held by one 5/8" hitch pin and one 5/8" bolt

CAD mockup


Measuring Tongue Weight


Painted and Installed


Jet Ski resting on Skids





Replies:
Posted By: Air206
Date Posted: August-06-2019 at 3:31pm
That's AWESOME!    

But you could have just borrowed my pickup......................

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https://tinyurl.com/y6t5e3bu" rel="nofollow - 04 Air206
http://tinyurl.com/9urzgls" rel="nofollow - 91 Barefoot
78 SkiTiq


Posted By: Fabcon
Date Posted: August-07-2019 at 9:53am
Nice setup.

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1976 Ski Nautique 351 Escort
1984 Barefoot Nautique (Parting Out)


Posted By: 8122pbrainard
Date Posted: August-07-2019 at 10:10am
Matt,
Compliments to your engineering.

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/diaries/details.asp?ID=1622" rel="nofollow -

54 Atom

/diaries/details.asp?ID=2179" rel="nofollow - 77 Tique

64 X55 Dunphy

Keep it original, Pete
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Posted By: zwoobah
Date Posted: August-09-2019 at 11:33am
That's really slick. Nice work.

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1968 Mustang 16 - 351W powered



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