Boat falls back on trailer

[muskiedreams]

I just want to say that every boat and trailer combination is potentially different and how the boat's weight is distributed as well as how it is supported from bow to stern will make a difference. Some trailer configurations provide more and better support at the bow than others. Some bunk trailers have long bunks that may support the boat very well from the stern and way past midship. Some of them even have smaller bunks in the front on either side of the bow to provide bow support which help distribute the pressure over a fairly large area. Some roller trailers also have roller arrays in front to support the bow on either side and also spread out the pressure of the bow weight evenly over multiple rollers. These types of trailers do help a lot to spread out the stress over more surface area and therefore minimize potential damage at any one point from bouncing down the road. There may be some trailers that have shock absorbing suspension but most hit bumps pretty hard and most of the energy can translate to a jarring effect that needs to be mitigated. Some trailers, such as mine don't have a lot of support for the bow of the boat.

 

Mine is an aluminum boat (1990 Grumman 18 FT). The trailer (Shorelander single axle) has rollers spread out over the rear section but there is only one place the boat is supported forward of that besides the winch stand stop. There is a 12" wide centering roller at midship under the keel which is mostly for centering the boat while loading and unloading. Then there is one other roller about 8" wide under the center of the  bow just behind the point where the bow starts curving up. The boat was originally making contact to both of them. After a while trailering the boat, the keel became damaged from bouncing on the center roller. I figured the trailer and possibly the boat were flexing and that was causing the the keel to hammer against the roller. I was lucky the hull didn't crack there. I had it repaired (welded) and adjusted the roller so no longer made contact after the boat is all the way forward on the trailer. I later had a similar problem where the bow and the structural strip of aluminum at the center of the bow (which continues forward of the keel) both cracked from stress right where the front roller is. So I had to have it repaired (welded). That was when I realized that it was because the boat was bouncing on the roller, Not just caused by pressure from sitting on just one point in the front. I started using a ratchet strap off the bow eye to hold the bow securely down and have not had another problem in over 10 years except for having to replace the front roller occasionally. It would be much better if the trailer was configured with multiple roller hugging the bow on both sides but it has been working out ok now.

 

I have also had other problems with the suspension and ended up having heavier springs made and had a welder heavily reinforce the spring brackets after the second pair cracked. A couple times I was lucky to notice the problem before the axle tore out from under the trailer. This is a big reason why I recommended before about inspecting the entire trailer thoroughly at least once a year for stress cracks. You can't necessarily rely on the yearly DMV inspector to discover them.

 

It really would have been best to have a bigger and beefier trailer because I think the boat is the biggest that the trailer was meant for, and I added a 15 hp four stroke kicker and two big deep cycle batteries. So I think I may be over the weight limit. I don't know for sure because the printing on the rating sticker is totally worn off. I think sometimes boat manufacturers don't, or at least didn't back then, consider the possibility (or probability) that the boat owner will be adding more equipment to the boat and equip it with a trailer that will handle the additional weight and more than accommodate the size of the boat for many miles of trailering.

 

Sorry if I rambled on too long.

[Reel Doc]

On 9/10/2019 at 9:56 PM, Reel Doc said:

It seems every time I pull my 24' Wellcraft walk-around out of the water the crank slips a little leaving this space.  With the main and kicker motors weight on the back it creates significant teeter totter effect driving over little ridges or bumps.  Is the strap just getting stretched out or is it just a case of locking down the front with a second tie down of some sort?

Appreciate everyone's thoughts.

I know you all have waited patiently to see how this turned out.  Note the photos below compared to the original and you see the yoke had slid back to the cross piece.  By moving it forward to it's original location all the motor weight is no longer hanging off the back of the trailer.  Now it rides nice and smooth like any of the livestock trailers or campers I've towed in the past.  I believe that yoke has been slowly sliding back since before I bought the boat as it's always porpoised, just been getting worse.  Having never towed a boat before I didn't know better.  Note we have a safety chain now too.

Thanks Hank, /L&M

[Sk8man]

Thanks for sharing that solution. I don't think any of us actually thought of that as we were focused on the winch and strap stretch  which is the more common problem.  Another example of Hank the superhero coming to the rescue

[horsehunter]

I'm glad you solved your problem. I'm failing to understand how the post slipping back creates more gap rather than less.

[Reel Doc]

1 minute ago, horsehunter said:

I'm glad you solved your problem. I'm failing to understand how the post slipping back creates more gap rather than less.

When it had slipped back the entire boat was that distance back on the trailer so the outboards hung off the back end of the trailer. All that weight would cause even more slide back when taking the boat out of the water.  A couple times last summer when disconnecting from the truck the front end of the trailer would pop up a foot in the air.  

Thankful I never had to take it very far as  a disaster waiting to happen.  However, after leaving it with Hank I now know how to get to Lake Ontario so longer trips might start to happen soon.