I have a 38' sonic on a Rocket aluminum trailer. The bunks stop at the transom notch, about 6" before the transom. Is this enough support to prevent a hook in the hull? I am considering moving the bow stop forward to get close to the transom, maybe 1" before it so I don't break the speedo pitot. But I don't want to mess up the trailer balance. It tows very well as it is.

My bunks extened 6" past the transom.

I have the same issue with my Rocket trailer. My bunks stop about 10" in front of the transom. I'm going to take it to a trailer shop to see if they can move the bow stop forward or fabricate something better. I have a Formula 353. Let me know if you find anything out. I know I need more tongue weight, I can actually see my bow kind of teeter totter it's so light up front.

This will eventually cause a hook in your hull. The bunks should be long enough to support the transom itself. Can you just fabricate longer bunks ...?

Yes, they need to extend to your transom. You also need to be careful with tongue weight. There was a video on here a few months ago of a trailer rig that started to sway. Once it starts, if you can't slow down and drive out of it, each sway gets a little larger, until the rig flips, pulling the truck with it. Tongue should be about 10% of total weight, but not over the hitch mfg's spec.

I third this. Ether hook or other hull problems.

I had a tongue weight problem with my trailer when I got it. I ended up extending the bunks further back past the end of the trailer, then moved the boat back.

I would first get balance correcty by moving boat up if you can. 10% -15% is what they say. I think ths depends on total weight of everything. Then get your bunks to end at the end of the transom.

Moving hte boat fwd will give more tongue weight. Make sure your safe. More tongue weight is better than not enough. Like mentioned. If the trailer sways you do not have enough tongue weight. Maybe you could move you bunks back 4" and move the boat up 2 ". I believe with a rocket alumnium tralier you should be able to move the bunks and the front crank is usually adjustable some as well....unless its moved all teh way fwd already. Then maybe the trailer is under sized.
Just a thought.

It's the biggest trailer Rocket makes. I think there is enough room to move the bow stop forward enough. Tongue weight doesn't seem bad now, we'll see once I move it forward. My dually doesn't squat much now, hopefully a little more tongue weight won't be too noticeable.

I would find a truck scale to determine your tongue weight first. A cat scale would be the best but make sure its a slow time of the evening to be able to crank your landing gear on the platform. Tongue weight should be 10% of the boat and trailer. You may be able to move the bunks back by drilling new holes and re-bolt. Trail and error process.

Truck scales are split where they weight the different axles. Just pull in where tongue is in one section and back axles are other. That way you will have tongue, back & total weight all in one weighing