Trailer measurements A25

[qboat]

I am planning to set up a trailer like Tribologist--that is, with a keel bunk back to where the skeg turns down. If anyone has a measurement from a plumb line from the bow eye, back to the aft end of the straight run of the keel, that would be super helpful. Also, from the center of the axles back to the same spot--that is, the aft end of the straight keel bunk. Finally, the length of the straight keel run from just before the skeg forward to where the keel turns up to the bow. I can get some of these by scaling from the line drawings and pictures, but it would sure help to get actual measurements. I hope I can get close enough to pull the boat out with a trailer rather than having her blocked, then working the trailer under her (curiosity killed the cat--miserlyness will likely kill me). Anyway, any help much appreciated.

[DesertAlbin736]

I'll see what I can do next time I'm over at the boat. I still have my plumb bob from my land surveying days plus a 40 ft steel tape. Meanwhile you can try scaling off this photo.

DSCN3628.JPG

[tribologist]

Missed this post completely . Are you still looking for the dimensions ? I been working ilin the CAD model of the boat and one of the things i plan to do is to model the trailer too.

[nebulatech]

I missed this one too. My trailer is in the back yard. Do you still need the measurements?

[tribologist]

That dimensions is 210 inch.

My axles are 48” forward from that same point

[tribologist]

47 actually

The keel bed is 138”

[tribologist]

I put the trailer in the cad file together with the boat. I would think most trailers has similar frame measurements. Once it's in the CAD system its trivial to branch it and make a version that is exact to a different trailer with the same architecture.

The second image show an issue we have with ours. It needs better guides on the keep to force the keel to center. Im thinking of adding a Vee cradle on the rearmost crossmeber to make it line up.

[DesertAlbin736]

Would be nice to be able to do a 3D print of that at 1 inch = 1 foot scale for a mantle piece display model or RC model. Even a half hull model to mount on a wall plaque would be cool. I used to work with AutoCAD during my working career but mostly did 2D circuit schematics & never really got good at 3D renderings. Now I don't have any of that expensive software to work with. Nice job!

[DesertAlbin736]

The second image show an issue we have with ours. It needs better guides on the keep to force the keel to center. I'm thinking of adding a Vee cradle on the rearmost crossmember to make it line up.

That's an issue that frustrates me to this day. The problem is the bow settles on the bunks before the stern does and the keel isn't deep enough for a V cradle to engage & center it before the front half of the boat is locked in place by settling on the bunks. The best solution would be guide boards up high on the sides about midships, which of course is right where the wheels are. V guides work great on a sailboat with a deep fixed keel or even those with swing keels.

Since our bunks extend all the way aft to within a couple inches of the transom what we do is make sure we get the ramp lane next to the dock. We float the boat back onto the trailer & cinch up the bow stop & the Admiral drives the truck while I stand on the dock with a stern line in one hand and a boat hook in the other to push-pull & guide back of the boat as she slowly pulls the trailer out of the water & I can see where the hull is supposed to land on the bunks.

DSCN3631.JPG

[tribologist]

I was thinking that way to but since it normally settle within a few inch It should be possible to guide it with a vee that is about 16 in across. The other thing I just ordered is a self centering roller for the very front. As the boat is pulled, it will rest only on that point and the winch roller. As the trailer is pulled, the boat will follow those two points and should be relatively centered. I also have guide poles in the rear but they have about a 4" gap. Im thinking of putting soft covers on them and let them spring out over the midship bulge

[tribologist]

Onshape is free by the way. The only caveat is that everything you do is in the open domain. You don't even install it. It run in a web browser. Click on teh link and try it. The training material is very good. If you go through the first 6-7 lectures you know enough to do basic stuff. Lofting a hull is a challenge but thats done. After those lectures you would have no problem modeling up your own trailer.

I have a licence through FIRST Robotics but I typically let everything that is not proprietary be public. I benefit so much from others sharing cad models.

[tribologist]

Here are the guides in the model

[tribologist]

Here it show better how I think it will work with the extra roller. As I crank it in, it will touch the bow roller and the new keel roller, as I start pulling up, The bow will lift up and actually loose connection with the bow roller but If I then pull it back in it will end up as the second picture and then the third.

[tribologist]

Looking at this I am thinking I should get a roller for both the two forward cross members and maybe cut the board back and let that cover only the last three cross beams. That should really help on shallow ramps. Guess I'm bringing the chain saw to the boat ramp....

[tribologist]

The second image show an issue we have with ours. It needs better guides on the keep to force the keel to center. I'm thinking of adding a Vee cradle on the rearmost crossmember to make it line up.

That's an issue that frustrates me to this day. The problem is the bow settles on the bunks before the stern does and the keel isn't deep enough for a V cradle to engage & center it before the front half of the boat is locked in place by settling on the bunks. The best solution would be guide boards up high on the sides about midships, which of course is right where the wheels are. V guides work great on a sailboat with a deep fixed keel or even those with swing keels.

Since our bunks extend all the way aft to within a couple inches of the transom what we do is make sure we get the ramp lane next to the dock. We float the boat back onto the trailer & cinch up the bow stop & the Admiral drives the truck while I stand on the dock with a stern line in one hand and a boat hook in the other to push-pull & guide back of the boat as she slowly pulls the trailer out of the water & I can see where the hull is supposed to land on the bunks.
DSCN3631.JPG

The problem is if the trailer is not level or if the boat is listing to the side. There is nothing the side bunks can do then. I think the key is to allow the keel to drop into a vee.. Maybe the rockers is messing a bit with you but the self centering rollers should help as you crank it up forcing it to center. When you have it fully cranked up, it rest only on one roller pair on the keel and the bow roller. as soon as you pull up the winch will slack as the boat rotate around that roller pair. allowing it to go side to side and find it way in the craddle. The side guides will just ensure it hit the vee.


I will try. I think it will work on yours too.