Trailer Design Feedback

Thread starter #1
I recently acquired a Jet Ski trailer on CL for $150 that I've repurposed for my Sunfish. In the interests of getting on the water this summer, I decided to modify the Jet Ski bunk system and pad them with foam swimming "noodles" to hopefully cushion the boat. The rear six feet of the boat are hanging off the trailer (Basically everything behind the cockpit), do you foresee this creating undue stress on the boat?

I appreciate any feedback on my efforts so far!
 

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#2
Having recently repaired some damage done to my boat by my first, less-than-adequate, bunks, I can speak with some experience. I would try the boat further forward on the trailer, with the bow almost to the winch. That should leave less hanging off the back and decrease the weight on the rear bunks. Anything you can do to increase the area of the bunks will mean less force on the hull. I also think that the keel and the chine (where bottom meets side) are probably the strongest parts, though a lot of boats seem to have keel damage.

Attached is a picture of my 2nd (hopefully last) trailer set-up, which just hauled my boat 5 hours without damage.


The cross pieces are treated 2x cut to fit the shape of the hull and padded with plush carpet over 1/2" thick closed-cell foam.
 
#3
Try removing all but the main leaf spring on each side of the axle (ie - suspension). When you stand on the empty trailer it should sink down 4" to 6". This will give the more cushion to the hull when trailering as a standard jet ski trailer with a suspension rated for 600lbs would be way too stiff for a 130lb Sunfish.
 
Thread starter #4
Looking at your picture, it seems like your rear support is only about 6" farther back than I have mine setup. It's hard to tell from the pictures but I've only got about 3 or 4" of clearance between the bow and the winch so I don't have much room to shift it forward. I'd prefer a little space between them to avoid knocking the bow off the boat if I had to brake hard. The Winch is mounted to a rather substantial pedestal welded to the frame of the trailer so I can't easily remove it.

I'm really hoping to get on the water this summer without much more effort, any thoughts on the least amount of work to use what I have so far?
 
Thread starter #5
Try removing all but the main leaf spring on each side of the axle (ie - suspension). When you stand on the empty trailer it should sink down 4" to 6". This will give the more cushion to the hull when trailering as a standard jet ski trailer with a suspension rated for 600lbs would be way too stiff for a 130lb Sunfish.
Well the trailer was apparently a deluxe model, it has a Torsion suspension so there aren't any leaf springs to remove. I don't think there is a way to adjust the load rating.

Link to Manufacturer Specs: http://www.tritontrailers.com/products/Model.aspx?CatID=29&SubCatID=41&ModelID=334&info=features
 
#6
Well, here's what I learned from a 1971 boat, newer boats may be different.
The weakest part of my boat hull was under the cockpit, there was nothing between the bottom of the hull and cockpit. This caused the hull to oil-can and epoxy resin spikes on the bottom of the cockpit to punch through the hull from the inside. I sprayed expanding foam inside the hull between the cockpit floor and hull. This part of the hull is now the strongest and where I place the trailer bunk supports. Behind the cockpit I have three foam blocks so this is also a safe place for the trailer bunks.

On a wood hull, the keel would be the strongest area. All the Sunfish keel consists of is a fiberglass hump. Placing weight on the keel concentrates stress in the keel area. I don't have the trailer rollers touching the keel, they do not do anything.

Best trailer I found is a 12/14' with coil springs and shocks for $150. Using bigger trailer tires made it ride even better. My Harbor Freight trailer with just leaf springs is terrible. Hit a washboard road pulling a rowboat and the trailer bounce to high I could see the whole inside of the rowboat.
 

Wavedancer

Upside down?
Staff member
#7
On my (problematic; but that's another story) Trailex trailer, designed for Sunfish, the stern of the hull is 4' 6" from the rear support bracket on the trailer. Or, in other words, the bailer is quite close to the rear support bracket.

I believe that the preferred way to support a Sunfish is with brackets that are perpendicular to the boat (and the internal structural foam).

I wonder how many miles/bumps the noodles are going to last. But do go sailing ASAP :)!
 

Wayne

Member Emeritus
#10
The weakest part of my boat hull was under the cockpit, there was nothing between the bottom of the hull and cockpit. This caused the hull to oil-can and epoxy resin spikes on the bottom of the cockpit to punch through the hull from the inside.
I don't think you are correct when you refer to the boat's construction as "epoxy". These boats are made of glass fiber reinforced polyester. The cockpit is bedded in pads of polyester resin. Ultimately, because of the double bottom and internal cockpit walls that area of the hull has the greatest reinforcement. Perhaps your hull experienced some sort of dramatic trauma causing the cockpit tub to catastrophically break free, leaving jagged edges at the broken bonds resembling "spikes".

When setting up a trailer to carry any lightweight boat, observe where the largest unsupported surface is ... that's the area to avoid loading. Right angles and curved stringers provide resistance against flexing. Flat regions, even with styrofoam backing, are the most vulnerable to constant pounding. Set up your bunks or cradles to carry the weight at the boat's most rigid point, the area as close to the chine as possible. NEVER carry weight on a roller, a roller's curve concentrates all the force along a very narrow line. Rollers can be ok as guides, but once the boat is loaded a roller should have daylight between it and the hull.
 

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#11
Another trick you can use is to let a lot of air out of the trailer tires -- maybe run them as low as 10 - 15 psi. This will take additional shock out big bumps in the road and help protect your boat. Normally this sort of thing would be a big no-no, but these boats are so light that the tires don't flex muxh even at low pressures, and thus don't overheat at highway speeds, and shouldn't hit/pinch on the rims when you hit those big bumps. The heavier the trailer, though, the more pressure you'll have to keep in your tires.

I would tend to think that multiple rollers supporting the keel, located at "strong points" (i.e. front and back walls of cockpit, daggerboard trunk, mast step) shouldn't be too hard on the boat, so long as they are used in conjunction with bunk boards. The more support locations you use, the better.
 
#12
Great thread ! I am currently focusing on my trailer too. I am aborbing all of the input from everyone. If I can add one thing though, looking at the rear shot of the "noodle" set up, it looks as though the noodles could move around, and with the straps tightening the boat to the noodles, if one noodle starts to shift, the strap needs to be tightened down to adust to the change. And since there is no bow stop, the boat could easily shift, ( causing a possible dissaster on the roadway?) just from one noodle movement.
IMHO, I like the idea of perpendicular padded supports. putting too much preasure on un supported areas, could be problematic. Think about how much preasure is needed to keep the boat on the bunks, if the bunks start to press in ward on the hull, I think it could be the start of hull damage.
Here are some pics of mine, no PT here,( things could change as I go, maybe later when I'm more permanent) and I don't plan on putting it in water that deep.
 

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#13
I think too much of the boat is hanging over the back without support which is why I think the boat needs to come forward on the trailer if possible. I would take the winch off so you can move the boat further forward. You don't need a winch for this boat.
Then mount cradles which are perpendicular to the hull (look at the pic davavd posted) one cradle mounted where your most forward set of pool noodles are and one set mounted across the supports for the jetskis. If you can, try to have three cradles, two sets on the supports for the jetskis and one forward of those. I would build the cradles to go all the way to the edges of the hull.

Where your pool noodles are on the hull is going to constantly flex with each bump no matter how soft the trailer rides which won't be good for it. And if you store it on the trailer, you'll eventually get dents in the hull.
 
#14
I think the boat needs to be moved forward. It overhangs the rear of the trailer too much to reasonably expect anyone driving a tall vehicle (think semi) to be able to see the brake/running/turn lights at a regular highway distance. Nothing will hurt your Sunfish more than having her aftermost 6 feet ripped off by a bread truck.
Just my two cents...
 
#15
My first thought after I looked at the pictures was not the problem of having the rear of the boat sheared off ( a very valid concern) but the issue of the weight. With that much of the boat behind the axle there would be almost no weight on the tongue. Low tongue weight would cause a massive amount of fish-tailing. Personally, I'd vote for moving it as far forward as you can. As others have mentioned, lights and hull stress are concerns too. It would be tragic to get to the lake and find out you only have the front half of your fish. :eek::eek::eek:
 

predator

Fear the 'fish!
#16
Great thread.

I just got my boat and used the stock Northern Tool trailer. I adjusted the width and height of the bunks to put them parallel and just inside the outermost edges of the hull, and the keel just resting on the rollers.
After reading this I'll add some more padding on the bunks to raise it off the rollers a bit and modify the springs.

I drove it 8+ hours on I-95 and don't think anything broke or dented. I'm anxious now to get home and check it! There were a few serious bounces along the way, but all the straps were still tight.

Here's a pic. I can't wait to get it in the water!
 

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#17
I don't think you are correct when you refer to the boat's construction as "epoxy". These boats are made of glass fiber reinforced polyester. The cockpit is bedded in pads of polyester resin. Ultimately, because of the double bottom and internal cockpit walls that area of the hull has the greatest reinforcement. Perhaps your hull experienced some sort of dramatic trauma causing the cockpit tub to catastrophically break free, leaving jagged edges at the broken bonds resembling "spikes".
Ok, it was spikes of polyester hanging down, that I am sure of. They probably construct the boats a better today then they did in '71". Anyway, I could looked in the inspection port and see the gap under the tub which is still firmly attached to the deck. I could reach under the tub and feel the spikes which were directly over the impact craters the pushed through the hull out from the inside. The hull at this point was able to oil-can nicely into the spikes. The other side of the hull had the bailer unit which was keeping the hull from flexing. I also had stress holes in the bottom of the tub from lack of support. Good old expanding foam took care of my problems. From what I understand, they use to use some sort of 'Glue Disk' or 'Caulking Disk' way back when to attach the tub to the hull. It coule be the spikes were the remains of a failed application.
 
#18
Predator, I was driving down I-95 myself, and guess what I found on the side of the road? Yes.... the aft 4 feet of your Sunfish. But what the heck.....cut a few inspection ports here and there and fixing it will be a snap. Cheers
 
#19
I recommend you transport your boat upside down supported by the deck.

Alternatively, you can transport it on one side.

Do not transport it on it's bottom. You will ruin it.
 
Thread starter #20
I recommend you transport your boat upside down supported by the deck.
I've heard the recommendation to carry the boat upside down before, why is this better for the boat than bunks supporting the hull right side up near the chines?

Any advice on how to carry spars/mast when trailering a SF upside down? I've looked at buying an 8' PVC tube to carry beneath the boat attached to the trailer frame but it would have cost almost $150 to buy enough 8" PVC to carry the spars.

Any cheaper alternative methods for carrying them beneath the boat?
 
#21
I've heard the recommendation to carry the boat upside down before, why is this better for the boat than bunks supporting the hull right side up near the chines?

Any advice on how to carry spars/mast when trailering a SF upside down? I've looked at buying an 8' PVC tube to carry beneath the boat attached to the trailer frame but it would have cost almost $150 to buy enough 8" PVC to carry the spars.

Any cheaper alternative methods for carrying them beneath the boat?
$150 would be money well spent. Just think. You can seal the sails up in there and know that they will stay clean and dry.

I am building a trailer to carry six Sunfishes and enough 8" PVC to carry seven rigs. I know it will cost me, but I don't think anything else will work as well. I also would prefer to store all my Sunfish boats and gear on one trailer. I can then shrink wrap the whole thing or simply tarp it for the winter.

It would be best if you had both the spar bag and the PVC tube.

If you are looking for cheaper options, I'd definitely invest in a $50 sail and spar bag. If you can store the spar bag indoors, you could probably get buy with just this. A couple of bungee cords will hold it down on the trailer. Bungee cords will cause some wear and damage to the sails, so pad the area you bungee well.

 
Thread starter #22
$150 would be money well spent. Just think. You can seal the sails up in there and know that they will stay clean and dry.
I guess it's all a matter of perspective, I only spent $200 for the whole boat (Which is in good shape but not pristine by any stretch of the imagination) and $150 for the trailer so I've had a hard time justifying $150 for PVC.

Are there any cheaper pipe options than PVC? I've been looking into drainage piping but haven't found a suitable alternative yet.
 
#23
I am not sure where you are at in your design, but here are some specific suggestions.

1. Your front support is actually a bow support. It is made to keep your boat from moving forward so you do not have to strap it as tight and you can move it forward as many have suggested. Unbolt it and move forward and rotate down so it rests on the near vertical portion of your bow without hitting the deck lip. You can use your wench to hold the boat against this support.

2. Buy a couple bunk board supports from your local marine shop and make the bunk boards cross the length of the boat as previously recommended by 67 stang, except they need to go the full width of your boat. The strongest portion of your boat in bending are the sides.

Here is how.
http://www.shortypen.com/boats/holder12/bunk.htm

3. Keep your boat upright to make it easier to launch, unless you are storing it outside over the winter. When I bought my boats they both had hull damage due to filling up with water and leaves and then not having proper support.

4. I have not figured out the spar storage issue. It seems that more often than not I have to put my sails away wet, until I could get home to dry them out. I would not want them closed in a pvc pipe with no ventalation. Maybe someone has a half pipe idea. It seems most people use some sort of breathable spar bag and firmly attach that to the trailor.
 

Wavedancer

Upside down?
Staff member
#24
4. I have not figured out the spar storage issue. It seems that more often than not I have to put my sails away wet, until I could get home to dry them out. I would not want them closed in a pvc pipe with no ventalation. Maybe someone has a half pipe idea. It seems most people use some sort of breathable spar bag and firmly attach that to the trailor.
As BrainCorrel wrote, I like my spar bag (less than $100 store bought; assuming some sowing skills, you can make one yourself as well) and tie it to the deck/trailer. If my sail is wet, I raise it on land to dry; takes ten minutes or so. I use an old towel to remove any remaining droplets from the window.

PS: If it's raining :eek:, I take the whole wet kaboodle home and hope for some sun the next day.
 

predator

Fear the 'fish!
#25
How about sheet metal A/C duct? A quick check online came up with "theductshop.com" with 3-foot lengths of pre-formed 8" galvanized sheet metal duct for $13.22 each. Probably want to cover the sharp edges with some hose.

For airflow you could either use perforated pipe or cut some holes, then cover with a tarp (or shrinkwrap) for storage. Be sure there are no burrs on the inside to snag things.


I checked my boat and don't see any cracks or damage. I don't know if the internal foam blocks were damaged, but I'm hopeful. Everything looks just as I left it.

I have to disagree with the idea of perpendicular supports being better. The caveat "as long as they go all the way across the bottom" implies that the support needs to come mainly from the chine (the corner where the bottom meets the sides). And all the embodiments of cross supports are only a 2x4 wide which concentrates the load on a very small area and propogates any damage all the way across to the vulnerable parts we're trying to protect. Even having 3 supports is only 6" of area where you could easily have 36" bunks instead.
It seems to me that the message is to distribute the load over as large an area possible right at the edge. That says long longitudinal boards, preferably with an "L" shape to fit the bottom edge, and another generous support at the bow tip just to hold and center. Rollers under the keel could help with loading, but should not be touching during travel.
 
#26
I've towed just about every boat trailer in the world and seen just about every problem also as my dad owned a boat shop when I was in High School and I would pick up boats 200 miles away and tow them back.

If you going to be on the highway or going out of town you might want is to ADD weight to the trailer - and maybe lower the air pressure to 18-20lbs. I have a small trailer I tow behind my Harley and I did this with no problems in 10,000 miles.
You can buy lead or weights at a tractor farm store.

These small lightweight trailers bounce so much anything attached may be damaged.

-Erik
 
#27
Adding weight helps! Even when I pull my Sunfish behind my 1974 Honda 900 Motorcycle adding a little weight helps. When being pulled behind my Dodge Dakota I have a eazy-up, charcoal grill, and any other camping equiptment I can cram onto the trailer to help with fish-tailing and bounceing. If its just a day trip then I let some air out of the tires. Anyone around the central Texas area need a sailing buddy?
 
#28
i always used a jet ski trailer i picked up from a local boat shop. i just adjusted the skids in a little bit and it seems to support the boat well and pull nice.
 
#29
I'm currently working on converting my jetski trailer to a Sunfish trailer.. I have a simple A frame and my plan is to use a Sunfish clone hull as a cradle for my Sunfish.

I plan on seperating the StarFish's hull from its deck and attaching its hull to the trailer, thus giving me an almost perfect support for my sunfish while trailering..

I'm still working on how everything will work out but I figure this should be a good idea.

I'll post pictures as I work through it.
 
#30
Thats a pretty good idea, better protection from road hazards too. I just posted some pics of my trailer project. There on my profile. Check it out as I would love to hear some feedback on it from you all.
 
#31
I'm new to this. Are we not supposed to have the hull resting on or touching the rubber rollers? Do the rollers damage the hull while in transit?
 

Wayne

Member Emeritus
#32
I'm new to this. Are we not supposed to have the hull resting on or touching the rubber rollers? Do the rollers damage the hull while in transit?
Rollers..., YIKES :eek:

Rollers tend to focus the weight of the boat at concentrated spots..., the apex of each roller's curve.

Better to have the weight distributed over a wider area by using "bunks", long padded and carpeted boards that extend along about 50% of the boat's length.

The other good support system is "cradles". These run perpendicular to the boat and are formed to fit its contour, again padded and carpeted.
 
#33
I plan on seperating the StarFish's hull from its deck and attaching its hull to the trailer, thus giving me an almost perfect support for my sunfish while trailering..



..I'm trying to follow you on this....are you going to install the hull of the Starfish on to the trailer permanently, and then slip the Sunfish into the Starfish hull? How is the inside of the Starfish going to be shaped to fit the outside of the Sunfish? Am I visualizing this correctly?

Or, maybe I will just wait for the pics.
 
#34
Im following you 67stang.....some where on here is some pics of the inside of a Sunfish. Its is not a stamped pice of plastic. (Think of a trucks plastic bed liner) It looked more like layed fiberglass, which I wasnt expecting. Am I correct on this?
 
#35
Rollers..., YIKES :eek:

Rollers tend to focus the weight of the boat at concentrated spots..., the apex of each roller's curve.

Better to have the weight distributed over a wider area by using "bunks", long padded and carpeted boards that extend along about 50% of the boat's length.

The other good support system is "cradles". These run perpendicular to the boat and are formed to fit its contour, again padded and carpeted.
The trailer does have carpeted bunks as well, but I'm not sure if 50% of the hull is being supported. I'll have to measure it. I put together a message yesterday with photos, but after I spent 43 minutes completing it, I got a message stating that the moderator needed to approve my post. I'm still waiting and we really need to know if we are doing damage to our new Sunfish by using this trailer.
 
#36
Okay, I just measured the carpeted bunks and they are only 5 feet in length. Do the bunks need to be at least 7 feet for a 14 feet boat? I think we may be looking at having to invest in a new trailer. Not sure.
 
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