Trailer To Boat Fit

[kenmare]

Hi Fishraiders,

New boat, another potential problem.

I recently upgraded my little Savage Pintail dinghy and 4 hp 2 stroke Mercury to a larger and heavier 385 Quintrex Explorer and 15 hp 4 stroke electric start Mercury. But I decided to retain my old Brooker trailer, as it's in very good nick.

Problem is, the new boat's more than a foot longer than the old one. So with the trailer winch post moved forward as far as practical, so as not to risk damaging the towing vehicle, the boat sits on the rear rollers about a foot or so forward of the transom.

A mate of mine tells me that to ensure the weight of a boat is properly supported, a boat should be positioned on a trailer so that the rear rollers are as near as possible to the transom. Other people I've spoken to about this tell me it's not that important, and not to worry, but leave things as they are. Who's right, who should I believe?

I don't want to replace my trailer, so if there is a problem, what's the best solution? Is it possible to inexpensively modify my existing trailer so it better fits my new boat?

Regards,

Bob

Edited September 29, 2007 by kenmare

[chrisg]

kenmare

Bit more info....is it a multi-roller trailer or centre keel rollers and skids?

chris

[kenmare]

kenmare

Bit more info....is it a multi-roller trailer or centre keel rollers and skids?

chris

Hi Chris,

It's a multi-roller, one roller up the front of the trailer, three at the rear : a large fixed centre roller, and a smaller adjustable roller at each side.

Regards,

Bob

Edited September 30, 2007 by kenmare

[chrisg]

Bob

The original thought was that the centre or keel rollers take the bulk of the weight and the outer rollers support or cradle the boat to stop it moving around. There is a thought these days particulary with glass boats that the keel should take 60% of the weight with the side rollers taking the other 40%.

Your set however sound like the first and on a tinny thats probably fine. Yes ideally the last roller should be in line with the transom but I doubt whether its a big issue being a foot or so in. A 395 still ain't that heavy.

Two things to check -

Make sure the weight is across all the rollers....drop the middle ones until the weight is on front and back roller then jack them up until they are pushing firmly but not lifting the hull and lock them off. You can do a similar thing with the side rollers.

Most importantly check your tow ball weight on some bathroom scales. It wants to be about 10% of the total trailer/boat weight. If the boat is too far back it will be too light and can get unstable towing. It can be fixed with some mucking around.

Hope this helps.

Chris

[kenmare]

Hi Chris,

Thanks for the advice.

You've helped me a lot.

Much appreciated.

Regards,

Bob

[offtap1]

The boat hanging over 30cm from last roller wont be an issue if you follow this advice.

I would sugest that you ensure the rear outer rollers are as far out as possible towards side of boat which is were more strength is, these rollers should be set to balance boat with the keel roller supporting weight, but when you strap down you dont want to be pulling weight down on outer rollers positioned in middle of floor between keel roller and outer edge where there is not much strength, other than the keel the outer corners of hull are the next strongest point , especially since you have not only upgraded boat weight but added a heap with 15hp 4 stroke motor, so you want rear of keel to take weight and the outer rollers positioned close to outer edge of boat for much greater strength due to welded corner. The other point which was mentioned is to ensure your tow ball weight is at least 10% of total weight of boat, motor and trailer which will make a huge difference in towing. You can check this by placing trailer on weight bridge with jokey wheel down then just rolling rear wheels off weigh bridge and only place jockey wheel on scales. If you have moved your whinch post as far forward as practicle and weight on tow ball is much less than 10% then you will need to move your axle on trailer further back till you get it right. Hope i havent confused any one. Cheers Dave

[kenmare]

Hi Dave,

The outer rollers are set about as wide as they can go.

I've also adjusted them, so most of the weight is now on the keel (when I picked up the boat it wasn't).

I'll check the tow ball weight, but I don't think that'll be a problem.

Thanks for your help.

Regards,

Bob

[kenmare]

Hi Fishraiders,

As a post-script to this post, yesterday I finally gave up on trying to fit my old trailer to my new boat and motor, and did the sensible thing. I traded my old trailer in on a new one.

But not before I investigated having the draw-bar extended and moving the winch-post and boat 30 cm forward on the trailer, and realized that would only be creating a rust problem, at best.

After trading-in my old trailer, I'm out about another grand. But why risk damaging over six grands worth of new boat and motor? And I'll then have a brand new trailer, designed specifically to fit my new boat. Feel it's money well spent, and what I should have done in the first place.

Something any other Fishraiders planning to upgrade their boat might want to consider.

Regards,

Bob