Trailer cradle suggestions

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Trailer cradle suggestions

Postby SpeckledTrout » Sun Feb 03, 2019 9:44 pm

Hi, I have a DSII on an old aluminum v-hull trailer. The boat launches, retrieves and rides well on the trailer (I do a lot of highway miles to/from the coast). However I'd like to better balance the boat so that it's not so front-heavy. See photo. I'm not concerned about the tongue weight but I do believe the trailer would ride a little bit better if the boat were better positioned. Currently, the boat sits on 2 long carpeted bunks and also has 2 rollers to glide on.

My most important question is... are there particular pressure points (or reinforced areas) on the hull where I need to ensure I keep good hull balance (such as cradle width, cradle length, any roller suggestions, etc)? I ask because my last boat ( a Force 5) was very specific on where to apply load to the hull and building the cradle was exactly measured.

I'd value seeing any photos of other folks' trailer set up and any tips offered.

Much thanks.
Andrew2617
Regards,
Andrew
DSII #5996
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Re: Trailer cradle suggestions

Postby tomodda » Mon Feb 04, 2019 12:57 pm

Andrew:

I have a DS1, but look over here:

viewtopic.php?f=1&t=5853#p33536

First photo is side view of boat on the trailer, she is supported by two bunks and two keel rollers, one at stern, one about a 2 feet forward of the centerboard slot. Remember, the DS1 has a single hull, no floor, but I believe the hull pressure points are about the same. My boat is also very early, it has wooden seats, not molded in. Note that I have a stringer (long beam, going fore-aft) 'glassed into the hull (on the topside, of course) right about where the seat-front goes on the later DS1's, DS2, and DS3.

For what it's worth, I've just flipped my boat over for hull refinishing. The P.O. hadn't taken the boat off it's trailer for about 20 years, so I was really eager/afraid to examine the bottom up close. Good news - the bunkers did not deform the hull at all. Flipped upside down, the hull shaped was still perfect. Bad news - a whole network of gelcoat cracks and even some chips radiating out from the bunkers. No surprise, I guess, but aggravating work to fill in. More significantly - and this is completely unscientific - I went over the entire hull pressing in with my hand and putting my weight on it to see where the hull flexed significantly.

Long story short, the spot that flexes the most is just forward of the stringers on my boat/the seat front on your DS2. Approximately next to the hinge of the centerboard. This is also right in front of the trailer bunk (at least in my boat), running for about 1.5 feet in from the front of the bunk, on the planing section of the hull - the flat part. That area is very soft, was full of gelcoat cracks on my boat and I could flex it 1.5-2 inches with a good push of my hand. Again, no surprise, I noticed that the same are flexes from the inside when I step on it. From inside, the weak area is from the line of the cuddy opening and forward about a foot or two. Looking at your on-the-trailer photo, it's about the same place, in front of the bunker and behind the mast.

My conclusion? I need better trailer support in that area. I have some nice 2x8's sitting in my lumber pile, I'm thinking of using them for new bunkers, about 2 feet longer going forward than my present bunkers. But I don't know if such a bunker would actually touch the hull (support it) all the way along it's length. I'll so some testing while the boat is still upside down. I may have to build up the front side of this proposed new bunker, otherwise I'll have to rig some sort of cradle. Keep an eye on my DS1 post (#37) and you'll see what i wind up doing - eventually.

Best,

Tom
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Re: Trailer cradle suggestions

Postby GreenLake » Mon Feb 04, 2019 2:15 pm

My trailer supports my DS1 with rollers for the V section of the hull and under the CB trunk (to support the CB as well). Those areas are strong enough to be supported by rollers. Any other rollers are positioned a bit lower so that they support the bow as the boat is launched/retrieved, but do not support the boat while on the trailer. In particular, the aftmost roller is lower by 1-2" and has a "notch". When retrieving, I lower that to the waterline and then push the bow so it rests on that notch. That aligns the boat and I can then winch it in straight every time. The bow runs up the rollers one by one and at some point the bunks take over and the back of the boat slides the last few feet. Took me some observation and thinking to calibrate this, but ever since launch and retrieval are a lot easier. (My trailer has a hinge, which I use for launching - the steeper angle requires less push to get the boat moving).

I have two flat bunks in the rear. Since I have a DS1 with the molded seats, they reinforce the hull where they are connected to it. My bunks are place to support the boat along that line. Over the years I've made them wider and they now extend further back.

I don't observe any denting from storing the boat this way, and the distances I trailer are average to less than a dozen miles per trip. If I tried to take the boat cross-country, I might rethink this further. For bunks there's only one rule: wider and longer.
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Re: Trailer cradle suggestions

Postby Zinger88 » Thu Apr 25, 2019 11:10 am

I did a thread awhile back on how I revamped my old trailer with new bunks. Hope you'll find it useful...

https://forum.daysailer.org/forum/viewtopic.php?f=11&t=5422
Last edited by Zinger88 on Thu Apr 25, 2019 4:36 pm, edited 2 times in total.
Jim H
'76 Daysailer II, Sail #7920, Windsong
Burton, TX
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Re: Trailer cradle suggestions

Postby GreenLake » Thu Apr 25, 2019 1:51 pm

This is beginning to look like a thread that collects all the good info on setting up trailers.

I'll move it out to the Repair&Improvement section, as it really is not specific to any model version of the DS.
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Re: Trailer cradle suggestions

Postby KenKorey » Wed Oct 09, 2019 3:58 pm

I've tried to follow zinger88's design in setting up my trailer -- at least as closely as undimensioned photos allow-- which is marked by its long center keel bunk flanked by shorter side bunks. This week I did my first retrieve and found that the center bunk held up the keel in back by the dome of the autobailer, allowing this contact point to support the keel slightly above the bunk all the way to the forward roller and the whole hull to wobble somewhat. Can anyone give me a suggestion for adjusting this? I'd hate to remove my autobailer after all the restoration work I've done to keep it in working condition. I''ve temporarily solved the wobble problem by driving two thin wedges on either side of the autobailer which does elliminate rocking, but I'd really like to have the center bunk support the the keel more completely.

Ken Korey
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Re: Trailer cradle suggestions

Postby GreenLake » Thu Oct 10, 2019 2:42 am

If you have a high spot on the hull, placing a bunk there won't do very much for you.

If you have really wide bunks, you may not need to support the centerline / keel (other than in front). If the center bunk is mainly to support the bow while launching / loading then you could lower it a bit. The bow would slide along it, but once the rear bunks take the weight, they'd lift the boat off of it.

I'm doing something like that with my rear roller, it's lower than the other ones and no weight is on it, except when the bow passes over it on launch/load.

If you want/need to support the CB, you could put a "step" into the bunk, raising the forward section a bit (but then you would need to use something for the transition, perhaps a bit of polyethylene cutting board cut into a ramp. CB would rest on the forward section, rear would hang free (but if you use wide side bunks, that's OK). (The bailer presumably is aft of the CB and would be unsupported).

That give you any useful ideas?
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Re: Trailer cradle suggestions

Postby KenKorey » Fri Oct 11, 2019 10:53 am

Thanks, Greenlake! This is exactly what I wanted to confirm. I'll shorten the center bunk enough so that the autobailer doesn't reach it, and then reinstall the dropped wide roller (which I just removed to accommodate a long center bunk) to help engage and guide the keel at retrieval. :roll: It all seemed like a good plan at the time.

Now I'm wondering how zinger88 managed with his lengthened center bunk? Looking more carefully at his photos, I note that his one image of the center bunk and hull from underneath the boat appears not to have an autobailer. Do you suppose that it's been removed?

Ken
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Re: Trailer cradle suggestions

Postby GreenLake » Fri Oct 11, 2019 7:51 pm

Not everyone has an autobailer.
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Re: Trailer cradle suggestions

Postby EricJ » Sat Feb 01, 2020 10:52 pm

Hi Everyone,

I picked up Sunny Daze in September, my first DS, and have slowly been working on the trailer. I was going to pretty much copy what Zinger88 did, but after I got the center bunk on the trailer, I ran out of time for the day, and quickly made up 2 temporary small bunks to keep the boat level. The two small bunks are positioned right where the bulkhead is, and they do a good job keeping the boat level. Now I'm considering not even adding side bunks, since these small ones seem to be doing the job. What do you all think? Is this a good idea? or should I add the long side bunks as well.

When I got Sunny Daze all the weight of the boat was on the side bunks, the keel wasn't resting on the center line rollers at all except for the bow, so the hull had some oil canning going on.
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Eric
1974 DS II Sunny Daze (but thinking of a new name)
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Re: Trailer cradle suggestions

Postby GreenLake » Sun Feb 02, 2020 1:09 am

The setup you have as you show it is almost the worst possible configuration. The only thing worse would be a bare broomstick (point load).

Yes, they keep the boat level, but whatever loads they do support would be very concentrated. If the boat rests on the keel, it may be that you can place these low enough to they don't take too much weight, but that won't work when the trailer is in motion (and it will tend to pull the boat open, if it rests only on its keel).

Get another pair of those little support brackets and mount them in the back, then connect with some boards that are 8-12" wide and backed by a "spine" of 2x4 of 2x6 to stiffen them a bit. Not that much work and your boat might avoid some "dimples".

PS: it's not just the dimples you see when there's static load, but when you trailer, the laminate is flexed at the edge of the support and will quickly get weak.
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Re: Trailer cradle suggestions

Postby EricJ » Sun Feb 02, 2020 1:35 pm

GreenLake wrote:The setup you have as you show it is almost the worst possible configuration. The only thing worse would be a bare broomstick (point load).

Yes, they keep the boat level, but whatever loads they do support would be very concentrated. If the boat rests on the keel, it may be that you can place these low enough to they don't take too much weight, but that won't work when the trailer is in motion (and it will tend to pull the boat open, if it rests only on its keel).

Get another pair of those little support brackets and mount them in the back, then connect with some boards that are 8-12" wide and backed by a "spine" of 2x4 of 2x6 to stiffen them a bit. Not that much work and your boat might avoid some "dimples".

PS: it's not just the dimples you see when there's static load, but when you trailer, the laminate is flexed at the edge of the support and will quickly get weak.


Thanks for the feedback! I'll continue with Zinger88's configuration!
Eric
1974 DS II Sunny Daze (but thinking of a new name)
Sahuarita, AZ
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