Four Winns 240 Horizon hull design - porposing

[DaleG]

Four Winns has a long history in a good portion of their Bowriders and Cuddy's of using a hull design wiht an extended hull surface on either side of the I/O engine. I just purchased a 2003 Four Winns 240 Horizon and while I have only had the boat a month I believe I am experiencing a downside to this hull design and am interested in comments/opinions.

The boat is powered by a 280HP volvo duoprop sternrdive -- so it has plenty of power -- and with the drive trimmed in -- and with the extended running surface hull -- It literally pops onto plane --- that is the good part --

However -- I find that the hull is very intolerant of much bow lift and actually goes into porposing (at even medium throttle -- say 3200 RPM / about 32 MPH and on plane ) if you even trim the drive out very much. (When I sea trialed the boat the dealer even mentioned that most people leave the drive trimmed in all the time -- I though this was just a dealer/non owner who really doeally use the boat every day comment)

I find that not being able to trim the bow up much -- and having more control over proposing is not what I really desire in a good powerboat hull
(I had an old 21 foot cuddy which had no such issues for years -- trim was very effective and when properly trimmed the engine speed was lower/and or top speed increased as wetted surface decreased )--

First I am interested about thoughts about the hull.

Next -- I do have some trim tabs I removed from my other boat -- ( they were highly effective in getting the old boat onto plane) Which I am considering adapting and fitting onto the Four Winns -- (might not be easy)
My thoughts are this -- If I can provide stern lift through the trim tabs -- than I should be able to trim the dirve out more (and therefore have a more parallel to the hull prop thrust ) which should be a more efficient running configuration -- I should get -- more ability to adjust trim -- and the ability to control porposing -- even though the hull design will never allow me to run with a higher bow position due to the extended hulll surface getting into the water more.

Any thoughts on this situation??????

I have a major in engineering and a minor in Naval Archetiture -- and have been around boats (and a few ships) for years -- but I have never really practiced in the field -- so while I am slightly conversant in marine lingo -- I do see a lot of the design people on here are way beyond what I remember from college --

thanks for any assistance and thoughts --
DaleG -- West Palm Beach FL

[Ike]

I have been around Four winns for many years and never heard that this was a characteristic of their boats.This type of hull design with the hull planing surface extending aft of the stern drive is very common in the industry. I suspect it's more of a weight distribution problem. Move some weight forward or aft and see what happens. Longitudinal distribution of weight is very important in planing hulls. The LCG is deliberatlely designed to be as far aft as possible, to reduce wetted surface when on plane. But if it's too far aft, you can get serious porpoising problems. If It's too far forward they bow doesn't rise as well as it should and can cause steering and other problems.

Also trim and tilt can be the cause, as well as trim tabs. If the boat has trim tabs this might be a cause. Make sure everything is in a neutral position, then try it. Vary one thing at a time to see what happens. Move some weight foward a few feet. Try it again.

Years ago a friend had a boat that was very sensitive to longitudinal weight distribution. Moving one person forward or aft 2 feet made a difference. Of course it was a smaller boat than yours but the principle is the same.

If all else fails call Four Winns 231-775-1351.

[middlejohn]

Hey Dale, I just purchased a 2002 Horizon 240. Did you ever get your planing problem worked out and what modifications did you have to make?