2001 OUTRAGE 21: Change to Garboard Drain Plug from Rubber Compression Plug

[GSBWhaler]

Q1: on a 2001 OUTRAGE 21, would there be any problem created by changing to a bronze garboard plug from the rubber compression plug for the transom bilge drain?

ASIDE: I have always felt more secure with the bronze garboard plug compared to a rubber drain plug.

I recently acquired this 2001 OUTRAGE 21. I am doing a complete refit. I am considering changing this drain plug.

[jimh]

Q1: on a 2001 OUTRAGE 21, would there be any problem created by changing to a bronze garboard plug from the rubber compression plug for the transom bilge drain?

Typically in Boston Whaler boats the rubber drain plugs that use compression to seal are installed from the inside of the boat to block water from draining out of a sump area into the sea, and, of course, at the same time to block seawater from coming into the boat. In most instances where those plugs are used, the sump area drain could also be left open, as the location of the sump drain relative to the static waterline of the hull would not be very far below the waterline. As a result, seawater would only enter into the sump and rise to a level of a few inches, and by design not overflow the sump area. (One big exception to that rule is the forward cabin sump drain on a REVENGE, which if not kept plugged will allow the sump to accumulate about a foot of water and a rather impressive volume, too, as the bottom of that sump well is quite deep compared to the water line. However, when the boat is on plane, all the water will drain out and the plug can be put back in place.)

The bronze "garboard" drain plugs (that I am familiar with) are usually installed from outside the hull to close a drain whose outlet is very far below the waterline. Note that the term "garboard" traditionally means the hull strake next to the keel, or the lowest part of the hull that is not the keel.

A garboard drain plug is usually seen on boats that are able to be put onto a trailer or perhaps onto a lift, and the drain plug would only be removed to allow water that has collected in the boat's bilge to drain to the ground when on land or on a lift. Putting the boat in the water with a missing drain would mean significant down flooding of the hull's bilge area.

The general design concept of the Boston Whaler Unibond hull is there are NO BILGE areas. The portion of the hull that, in other boats, would be called the bilge is filled and sealed, in a classic Boston Whaler boat, with foam. The Unibond hull is really a double-bottom hull with its interior volume filled with foam and sealed off. The design of the inner hull or the liner provides molded-in well or sump areas, and typically all of these sump areas will have a drain path through the hull to the sea.

The particular boat under discussion here, a 2001 OUTRAGE 21, was designed and manufactured under a new era of leadership at Boston Whaler, and it is using the "Accutrack" V-hull design. It might have what was called a "Duobond" hull. This style of construction might have created bilge spaces, as the the amount of volume between the main hull and the "Duobond" liner was much smaller than on the Unibond hulls, and as a result there would be more open space where water could collect.

Getting back to your question, if the outlet of the hull drain that you want to change its plug type is located rather far below the waterline (at often a deepest part of the V-hull transom) and the normal location of the plug is on the outside of the hull, I would expect that a bronze threaded plug or "garboard" drain plug would be appropriate.

On the other hand, if the drain you are asking about is just an engine splash well drain, I don't see any reason NOT to keep using the rubber compression plugs. They work very well.

As you mention, you are doing a "refit" so why not refit with the type of drain plug with which you are most comfortable?

Of course, to fit the thread bronze garboard drain, you will have to make a significant change to the existing drain if it was not intended for that type of plug.

[GSBWhaler]

Thank you for your thoughts. The drain is 12-inches" below the water line and 6-inches up from the bottom of the transom.

[jimh]

ASIDE
The 2001 OUTRAGE 21 is quite a handsome boat, and at a hull weight of 3,000-lbs it is a husky boat, too. Its swamped capacity rating of 5,200-lbs is particularly outstanding. It's truly an unsinkable legend. Typically you get that huge swamped capacity when the space between the hull bottom and the hull liner has a very large total volume and is filled with foam. Having all that space filled with foam means the amount of water that can collect in the hull is limited, so thus a big swamped capacity.

Note that in the printed catalog for 2001 there is an important note at the back on the specifications page. The note advises that all the hull weight figures in the interior pages are to be superseded by the weights on this back page, which apparently were applied by to the page by gluing on a small printed strip to re-do the weight column. The original hull weight on the OUTRAGE 21 page was actually the same 3,000-lbs so no weight changed for that model.

[jimh]

The drain is...6-inches up from the bottom of the transom.

That sounds to me like there must be six inches of foam below the level of the bottom of the sump that is being drained.