Trailer Bunks

[kkearns]

Can anyone tell me the recommended width (distance apart) the two bunks should be on a trailer for a Daysailer. I bought my '65 DS1 last year with a trailer that is structurally great, but not designed for the boat. It is a "Tracker" trailer, probably designed for a fishing boat of some type. I don't have the measurements handy, but I believe that each bunk (port and starboard) is about 8-10 inches from the centerboard of the boat. Is this too far inboard? There are no rollers on the trailer and just yesterday I did manage to rig a canvass strap to support the centerboard. I don't travel with the boat often, but it does sit on the trailer all the time (I sail out of a parking lot at a state park).

Thanks,
Kevin

[Roger]

On the DS I the stringer is located outboard immediately adjacent to where the seat front meets the hull. The trailer bunks should be co-located.

[kkearns]

Thanks. Just so I am clear, you mean immediately "adjacent" outboard of the seat front, correct. In other words, if the stringer were "visible" it would be just inside the seat mold?

Thanks,
Kevin

[GreenLake]

The seat edge itself provides support, so you can line up the bunks with it.

[K.C. Walker]

Okay, I'll add my $.02 on trailers. I think that trailers that are improperly supportive of the boat do more damage to the boat than just about anything short of running up on rocks. The reason I say this is that even though you're just carrying a 575 pound boat the shock load of going over bumps is far higher than that. Most boats are supported by pretty small contact points, i.e. rollers and small bunks. The pounds per square foot on the small points is tremendous with the shock load and quite a bit just sitting on the trailer in the yard.

The Daysailer is a pretty flexible hull in the flat areas so the boat bounces quite a bit (and flexes the hull breaking down its stiffness) if you support the boat in those areas. My recommendation is to use rollers only under the keel and centerboard area and make the bunks as large as possible and straddling the seat front.

I'll admit to being Captain Overkill with my trailer. I basically made a crib that sits on top of my trailer. I made it as a bunks style trailer but the bunks are 2 x 12 x 12' long and they are contoured to match the hull contours. They go from the transom forward and then I support the keel area in front of that. Right now I'm trying to figure out a hold down method that will keep the boat from being able to bounce at all.

Okay maybe it's $.03 worth.

KC

[GreenLake]

K.C. you were the one with the impressive dents in your boat from the trailer rollers, if I remember. Some of use go such short distance on our trailers that the shock load issue, while there in principle, doesn't become serious.

However, I agree with you that rollers are for the centerline only, and further, one of the rollers should support the middle of the centerboard, so it doesn't hang from the CB pin.

In my view, the natural length of the bunks is about the length of the seats, because that defines the length of the flat part of the hull. I don't know whether longer bunks, or bunks that have complicated 3D shapes will improve things enough to matter, but I'm not about to trailer across the continent, nor across the state, for that matter, so I won't find out.

Many people just wrap the boat onto the trailer with two straps. If you go for long distances, you might want to either fix the middle of each strap to a hard point on the boat, or split the strap in two. That's to avoid the boat twisting in the loops of the long straps and perhaps getting enough wiggle room to jump off the rollers.

[Roger]

so as greenlake states, lineing up the seat support with the trailer bunk will give you the location of the support. Measure the distance from the centerline, double it and that should be the distance between your bunks.

[pnichols]

While I am no expert on this, I had the same concern about bunk sizes and their position when I did a complete rebuild of my trailer.

When I purchased my DSI it had two bunks made out of 2x4 about 3 ft long set on edge with the rug in tatters and the bunk brackets about to punch a hole in the bottom of the hull.

Needless to say I built new ones. I did not really have any spec but just examined the hull and stringer positions and also looked at other trailers.

Here is a pic of what I ended up doing:



If I recall correctly they are 4x6 - 7 feet long.

While I have not had a chance to trailer the boat much. I do plan on trailering her on several hundred miles treks. So my approach was to build bunks that would be more than adequate at supporting the hull and all the bouncing that takes place on the road. As was stated earlier this is much more abuse than the hull will ever experience on the water.

The bunks are placed such that their inside edge is in alignment with the inside edge of the seats. The back edge of the boat is about six inches behind the end of the bunk. The boats hull starts to curve up at about six inches before the forward edge of the bunk.

Hope this description makes sense

Like I said I did not have a spec.