Re: Year and model of Sea Nymph
It really isn't about the length of the bunks.
It's the way a trailer carries the weight of the boat. The transom carries most of the weight, the motor, even on a 14' semi-v. The bunks support the weight of the hull, if most of that weight is on the transom, I'd prefer to have that weight supported by the bunks:
This ^^ pix may be a 12'. It isn't mine. But you can see that the bunk falls just beyond the bottom edge of the transom. So the motor's weight on the transom is fully supported.
Like I said, if you aren't towing it too far, or the road to the launch ramp is in really good shape (not rough & full of pot holes) the current set up might work well. Or if you make the bunks longer, even just 12"+/-, you might be able to move the winch post further forward, move the entire boat forward on the trailer, and have the transom land just on the end of the bunks. Hard to tell, since I can't see the entire tongue length & location of the winch post on the pix you posted.
In the pix I just posted, you can see that the rear bunk overhang is shorter then the amount of bunk that sticks forward mount, possibly half as long.
Moving the boat around on the trailer, adjusting the bunk length, the boats position on the bunks, and the axle location can change the tongue weight. So if it seems too heavy or light after you make a few adjustments, it may tow poorly & behave unexpectedly, so be careful.
Google
adjusting boat trailer tongue weight
You'll likely get lots of hits, same if you do an Advanced Search from the forum homepage.
If you do expect to tow the boat a great distance or over rough & uneven roads, the jostling & bouncing can, and has in many cases, damaged the hull where it sits on a bunk, w/out adequate support, like extended out to (or slightly past) the transom.
In extreme cases, particularly on fiberglass hulls, this damage is often a Hooked hull.
Google
Hooked Hull
On a lightly constructed tin boat, w/ undersized & poorly located bunks, w/ sufficient excess weight applied (like filling w/ water over a long period of time), a bunk might tear a thin aluminum hull as the hull attempts to sag around the bunk.... This is unlikely on your SN, as most that I've seen, even 14' semi-v's like yours, tend to be stoutly constructed. But a rough enough road, long enough tow or any combination of those, could certainly dent the bottom.
Hope this ^^^ helps..
John
EDIT: Might poke around in the
trailer & towing forum, lots of good info in there too....