Custom Marine & Welding’s
Turned-Down Cavitation Plate Modification

By Dave Casper


So, the boats are all put away for the winter. What would be a good thing to do to your rig during the off-season? How about having Titus Grisham at Custom Marine & Welding modify your gearcase with one of his custom turned-down cavitation plate / hydrofoils? This is a relatively inexpensive way to improve your boats performance as well as its drivability. Titus added this modification to my CLE gearcase and I could not be more happy with the results.

Most hydrofoils are big, ugly, bolt-on plates. While generally effective, who wants a slab of metal or plastic bolted onto their gearcase when, compared to some others, for around the same price you could have a custom sculpted hydrofoil that works well and looks like it came right from Mercury (or other manufacturers)?


While the idea behind turning down the edges of the cavitation plate is not complicated, making this modification effective, durable and good looking is more difficult. Titus starts by trimming off the edges of the cavitation plate. He then welds aluminum pieces onto the edges at the correct angle and then smoothes out the angles so there are no sharp edges. Once the cavitation plate has the correct shape, it is then painted using Titus’ proprietary paint formula – the same paint that he uses on his nosecone modifications that, by the way, are one of the few paint jobs that do not peel off with usage. In fact, Titus warranties his paint jobs with a 1 year warranty against paint peeling.

Because I sent in my gearcase to be modified, I could not do a back-to-back comparison with the before and after versions. However, being very familiar with how my boat handled before the modification, I can give my impressions of the differences. First of all, planning speed. This is probably my favorite improvement. With the modification, my boat can maintain plane at a much lower speed. I like this because at times I like to cruise around at slower speeds to sightsee. This allows me to do so even slower while remaining on a plane. A nice benefit to this is that fuel consumption should improve due to the ability to plane at a slower speed. The other major improvement is in the time to plane. The cavitation plate modification significantly reduces the time required to achieve plane which increases safety – less time spent with the bow in the air restricting forward vision, and also gives an edge to those who enjoy drag racing. Titus has reported that with a heavy Honda 225 HP four stroke test boat, acceleration time to plane was reduced from 8 seconds to 3 ˝ seconds. Of course times will vary according to boat / motor combinations. Issues with boat porpoising should also be reduced.


My Custom Marine & Welding Modified CLE Ready To Hit The Water

Are there any drawbacks to the modifications? No, there are not – there are only benefits to be gained. Give Titus a call for the cost of the modification - it is quite reasonable, and, he can work out package deals if other work is done. For this you get improved boat handling, performance and safety as well as a product that looks great and is made and finished to the same high standards as the other gearcase modifications that Titus offers.

Here is some more news from talking with Titus just today. If you want the benefits from a larger cavitiation plate but don’t want to send your gearcase out, Titus is now offering a bolt on plate that is actually wider than the welded version. Being wider, the benefits will be even more noticeable. This new plate is available either in plain aluminum or, for a slight additional cost, in an anodized finish. Also, Titus is developing a new hydraulic jack plate. Development is not quite done yet but rest assured, it is not going to be like your average jack plate. It is going to have some unique features and would be worth a phone call to Titus to find out more about it.

To learn more about Custom Marine’s turned down cavitation plate modification, nosecone modifications, or other services offered, visit Titus’ web site or give him a call. Do something productive during the winter – improve your boat!


Custom Marine & Welding
451 Locke Six Rd

Killen, AL 35645

(256) 272-0500


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