Katama 16 Bow Bouncing on Trailer

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
hermit
Posts: 20
Joined: Wed Jul 24, 2019 12:24 pm

Katama 16 Bow Bouncing on Trailer

Postby hermit » Mon Sep 16, 2019 7:50 pm

On the two trips I have made towing my recently acquired 1972 Katama 16, I noticed [the bow of the boat is bouncing on the trailer] when going over bumps. On the first trip I attributed the banging to the hitch ball and coupler. After that first trip I adjusted the ball clamp and hoped for improvement. What I found on the second trip is that the bow of the boat appears to be moving up 2 to 3-inches relative to the winch post top when going over bumps, and the bow's return to rest seems to be the main source of banging. I think this is because the winch height is such that the strap is horizontal when taut.

I don't like the banging, and see two potential solutions. One solution is to move the winch lower, so the strap holds the bow both forward and down. But I am not sure how low it needs to be, or how well that works when loading the trailer.

The other solution is to add another strap at the bow eye that holds the bow down. I'd rather avoid adding another strap, and I don't think it is common to do so, but I don't know.

I could play with adjusting the winch position and driving around on bumpy roads, but I thought I would see what experienced people say.

Tongue weight is about 100-lbs.

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Phil T
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Re: Katama 16 Bow Bouncing on Trailer

Postby Phil T » Tue Sep 17, 2019 7:57 am

While the winch cable pulls the boat tight, another important piece of hardware is the bow stop and its position in relation to the bow eye.

The bow roller should be touching the top of the bow eye. When the boat is winched, if the bow wanted to move up, the eye would be blocked by the roller.

On older 16'7" models, the bow eye was very low. With some winch posts the above configuration was hard to do. In these cases, a ratcheting strap (in addition to the winch strap) from the eye to the trailer frame is recommended. If there is no frame directly below, use a strap to each side of the frame to form a upside down V. These straps, in addition to the two transom straps, will keep the boat from separating from the hull.

(edit to clarify adding a second strap)
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jimh
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Re: Katama 16 Bow Bouncing on Trailer

Postby jimh » Tue Sep 17, 2019 8:13 am

Do not adjust the winch strap angle of pull to be downward. That will tend to make loading the boat harder, although with a small and very light boat like a KATAMA 16 it probably is not going to much different.

Or, add a second strap at the bow, from the bow eye to the trailer frame, pulling downward on the bow eye. I have used one on my trailer for many years.

Or move the winch lower. See an example at

http://continuouswave.com/whaler/cetacea/cetaceaPage05.html

hermit
Posts: 20
Joined: Wed Jul 24, 2019 12:24 pm

Re: Katama 16 Bow Bouncing on Trailer

Postby hermit » Tue Sep 17, 2019 11:53 am

Thanks for the replies. I will try a combination of the suggestions. I will see if I can orient the winch so the strap comes to and from the top of the spool when in use instead of the bottom. That will bring the bow eye much closer to the bow stop, and it will require lowering the combo winch/bow stop mount several inches. I will see if I can move the winch one extra hole down to add a little down angle to see if that helps.