Trailer questions
 

I recently purchased a used trailer and I had to move some rollers around because they were sitting under the strakes, I am not totally comfortable with the setup. I was told it had a 21' boat on it, it seems too small, the back of my boat hangs off 23"" past the last roller. I had read there is a 10% rule which I just make, I sent some pics, any thoughts?

Pix are pretty dark but looks like you have one roller on each side of the strake now. I can't see any keel rollers. Make sure you have them set so that the keel doesn't bang the trailer when the boat rolls off.

The overhang looks a little farther than mine but I would worry about the tongue weight setup first and live with the overhang. Is that what you meant by the 10% rule?
When you drive, does it sway like hell? That is the main question.

I see you have bottom paint. If you aren't trailering but a couple times a season and it doesnt sway, IMO go with it.

I had read that the overhang should not be more than 10% of the length of the boat. It does not sway, but I have only driven local and have not gone more than 35-40 MPH. Since the pic's I lowered the winch arm a little and slid the whole big arm coming up from the frame forward a little. If you notice the keel up in the bow is very close to the tube of the trailer ( 1-1/2") that worries me. Thanks

There is a 10% tongue weight rule too. tongue weight 10% of loaded trailer weight.
In theory, you go to a truck scale and weigh your whole rig, subtract your tow vehicle to get your loaded trailer weight.( I don't know anybody who ever actually did that..) or guestimate...V20~3000 lbs

Use a bathroom scale under the tongue at hitch level. Then adjust the boat forward or back to get 10%. ~300 lbs

Definitely put a keel roller on the forward and rear cross member. Otherwise, on a steep ramp the bow will smack the trailer as it comes off.

that trailer is quite a bit too short for that boat.

The 10% rule I use for trailer length is that a boat trailer needs to be the length of the boat PLUS 10% minimum


Having that much overhang on a boat with the engine in the rear (IE outboard, I/O or V drive) is a really good way to end up with a hook in the hull and a ruined boat.

Get those rollers within a few inches of the transom.

You need a 22' trailer minimum for a 20' boat...

Then yes you also need to get tongue weight right... I like 10-15%

Smoke nailed it. That trailer is way to short, and for the reason he mentioned. There is a phenomena called cupping. Basically, it happens when a boat sits on a trailer that's too short for a long time. The weight of the boat presses down onto the rollers (or boards) and actually puts a bend in the bottom of the hull in the unsupported stern. That in turn will act like extended trim tabs, creating drag and constantly trying to bury the bow in the water. In severe cases it will actually make the boat undrivable at high speed. If the boat is going to live in a slip most of it's life than I'd grudgingly say okay to your trailer, but if it's going to live it's life on the trailer than by all means get a different one.

The last rollers should touch the transom, or be very (1"-2") close to it. Once the boat is sitting on the trailer properly, then you adjust the axles either forward or rear to achieve the proper tongue weight. Finally, you then adjust the front bow post to cradle the bow when she is winched onboard.

Your trailer is undersized for what you are asking it to do. I'm sorry, but it's just too short, and I'd suspect that your trailer springs are too light for your boat's weight, making safe trailering impossible.

add to that the fact that living in the slip means NOT sitting on the trailer all winter...... 6 months is WAY too long to be improperly supported.

BUT, you can make it work for now by replacing the rear rollers with bunks. Mount them right on the swivels for the rollers and make them long enough to support the rear of the boat.

Just a thought.

they wouldn't be supporting anything... If they flex only 1/4" then the hull will be distorted enough to be damaged

Go bunk! Lots of threads on here like Genie Aye shows conversion. Drive on drive off with ease. Also offers better support of boat.IMO:nice: