Watertight Rigging for a Viking

By Mike Warjone

As you all know, Hydrostreams aren’t famous for their abundant freeboard (especially around the transom). Even the slightest ripple in the water will certainly fill the splash well, and will likely dump a couple of quarts in the through-hull openings. Throw a couple of people in the back, and you find yourself constantly feathering the throttle to keep the water out and the passengers in. I spend most of my boating life on the salt waters of Puget Sound. This area, while beautiful, often comes with an assortment of large tugboats, freighters, and pleasure yachts; vessels that leave humongous wakes. My last Viking had more hours on the bilge pump than the motor.

When I decided to upgrade to a new hull a few years ago, I wanted to rig the boat so that the transom area would be impervious to the constant deluge of saltwater. The standard through hull fitting with a rubber boot would last about one month in the hot summer sun and salt, so I needed something better.

The engine controls were easy, a couple of Rex Marine tubes and fittings made for a clean and watertight connection. These are a bit of a pain to force into the cowling holes on the 280, but a little grease and two or three people pushing for all they are worth will usually do it.

The steering cables exit through the standard starboard holes, and are sealed with marine caulk.

The hydraulic lines for the trim and jack plate were a bit more challenging. For this application I decided to have a local hydraulic shop manufacture braided stainless lines that would be plumbed through watertightNonconductive lines.jpg (108678 bytes) bulkhead fittings to the motor. For the inboard connections I used NON CONDUCTIVE hydraulic hose to complete the circuits to and from the trim pumps. It is very important that the braided stainless lines are insulated from the trim pumps, as Quicksilver pump motors are not isolated from the pump fittings. Using standard hydraulic hose for the entire fluid circuit will cause your new stainless lines to instantly weld to each other when the trim is activated. (Yes, I have the fused stainless lines to prove it…) The non-conductive hose is typically used for boom trucks that work around power lines etc, and is about half of the cost of Quicksilver trim hose.

A few other things to consider:

It is important to make sure that all of the lines and fittings have the same inside diameter, thus eliminating any pressure/ volume dynamics

I retrofitted the engine trim cylinders with standard JIS stainless hydraulic fittings. These are much easier to find and replace in a pinch than the Mercury fittings.

For this project I had the luxury of starting with an uncut hull, but I think that it would be worth the time and materials to shave the original openings on an older boat, and then plumb new lines. Your inboard components will thank you for it.


The finished product is a watertight transom that is ready for the worst. After 80 or so hours of operation, I have yet to switch on the bilge pump.

sideview.jpg (99241 bytes) Underside of Bulkheads The Rigging Compartment Lines Closeup


Good luck!


Thanks to Industrial Hydraulics in Tumwater Washington (360 956 7070), and Banjo Willie, who came up with the idea in the first place.