I'm thinking of adding a set of vertical guide-ons to my trailer. How far apart should they be relative to the beam of my boat? Two or three inches each side? Less? More? Thanks.
Ziradog, Your query:
Quote from: Ziradog on Jun 16, 2026, 02:37 PMHow far apart should they be relative to the beam of my boat?
Standard TSBB answer: It Depends.
The first dependency is the flexibility of the goal posts, relative to the hull.
This is because the beam of your sailboat is wider at the middle than at the ends, where the goal posts end up.
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In the above pic of
Urchin's trailer, that spacing is wider than the stern, but narrower than the beam; but the PVC posts are very flexible and they widen, to allow the hull to slide by during launch and retrieval.
Inflexibility, is another dependency:
In this pic of
Short Ribs' trailer the goal posts are closer together, but it's OK, because the hull is straight along its length. Also notice that these types of goal posts (A PVC tube sitting on a metal frame) have very little flexibility.
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These kinds of goal posts while rigid, are not a problem for the RIB since any oscillation from road bouncing is only bouncing against the rubber of the hull tubes.
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On the
Irish Pennant, the goal posts use the more flexible PVC tubing.
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They are however, much closer to the hull sides than they were on
Urchin.
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It's OK, because the much shorter hull puts the beam very close to the goal posts, so they don't have to spread as much past the mid point, compared to a more conventional sailboat hull.
They do have their own challenges, though:
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The forward fender is going to snag on the goal posts, either during launch or retrieval.
Hard to see from the pics, but the goalposts on the two different sailboats were about 2 inches from the sides. This is because while bouncing on the road, you don't want the PVC posts slapping against the rub rails or the gunnels.
I have an additional problem with the hull flaring out half way down, so I have a little more clearance, so as not to rub against the sides, during launch/retrieval.
As you can see, I'm a BIG Believer in goal posts on sailboat trailers.
Benefits (IMHO) are:
1) Makes it easier to see where the trailer is while backing in to the ramp, when retrieving the boat.
2) The trailer lights being so far above the water line, dramatically reduces light maintenance.
3) The trailer lights being in the face of drivers behind you, reduces chances of being hit in traffic.
(They tend to back off from the glare, especially at night.)
4) The PVC is very kind to gel coat and even painted hulls, and leaves no marks during launch/retrieve.
5) Helps center the boat, in a cross-ways wind, or cross-current retrieval, critical for a frequent single-hander.
6) Handy to steady yourself on, when climbing around, on and off the boat.
Disadvantages are:
1) Having to flip the bow line over the goal post after launch and before you bring the hull to the dock.
2) Dealing with fenders snagging on the goal posts, during launch/retrieval.
I generally flip the fenders inside the cockpit to launch and then flip them back outside, when I get the hull close to the dock.
Not a major problem since the goal post hardware that mounts to the trailer frame is adjustable, but the things you will have to consider are:
1) Whether to use all PVC goal posts, or PVC on metal supports.
2) How wide the beam is, relative to the stern.
3) Whether or not the hull curves hit the sides of the goal posts. If on the rub rail, no problem; if on the side of the hull, bears watching/adjusting.
4) How much flex you observe in the rear view mirror while on a bumpy road, or at speed.
For example, my goal posts are rock steady until around 50 - 60 mph+, then they "sway" (technically: oscillate) side to side in the wind, probably due to the aerodynamic drag of the lights.
As a general rule, they still do not hit the side of the rub rails, because they were adjusted that way.
Hope this helps,
Charles Brennan
Unole had a stub keel. So the guide posts mainly positioned her to enter the keel guides which were very close to the stub keel itself.
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Thanks guys. I've never seen flexible PVC guides, just the pipe on a post kind. Charles your list at the end is very helpful, and both teh sets of pictures were worth more than 1000 words.