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Montauk 17: Waterline and Transom Drains

Posted: Tue Sep 14, 2021 8:10 am
by Flynn
I’ve done a lot of digging and searching on what to look for when buying an older [MONTAUK] 17, but want a little reassurance about what I saw on a sea trial.

I read on the forum that the waterline going above the splash well drains means the hull foam may be waterlogged.

On this boat it was above the drain holes, but that was with two men, full 22-gallons of fuel, and a Mercury OptiMax 115-HP engine.

The [older MONTAUK 17 boat] got up and ran fine, and it was an absolute rocket once trimmed out. But I worry this is just because of the power of the 115 and not that the boat itself is dry inside.

Q1: Could water being above the splash well drains with that much weight aboard be a bad sign?

Q2: should the test be done with the boat empty?

Re: Montauk 17: Waterline and Transom Drains

Posted: Tue Sep 14, 2021 10:02 am
by Phil T
What is the waterline when the boat is empty of people at rest?

Re: Montauk 17: Waterline and Transom Drains

Posted: Tue Sep 14, 2021 12:11 pm
by Flynn
Phil T wrote:What is the waterline when the boat is empty of people at rest?

I'll be able to take a look when picking up the boat, but for now don't have that info. I met the seller at the boat ramp and the boat wasn't in the water without at least one of us aboard. Before I take delivery I can have him back it in just until the boat floats to be sure, but don't want to waste his time if there is a benchmark to compare to.

Re: Montauk 17: Waterline and Transom Drains

Posted: Tue Sep 14, 2021 2:59 pm
by Phil T
The OptiMax 115 outboard has a dry weight of 375-lbs. While this is significcantly more weight than the typical 90-HP or 70-HP two-stroke-power-cycle engine installed when the hull was new, it is NOT excessive.

The Honda BF90 engine weighed in at over 400-lbs.

If the drain tubes, inside and outside. are in good shape,[ engine weight] is not a concern. I would be more concerned with the drain tubes than the engine weight.

Re: Montauk 17: Waterline and Transom Drains

Posted: Wed Sep 15, 2021 7:36 am
by jimh
Flynn wrote:I read on the forum that the waterline going above the splash well drains means the hull foam may be waterlogged.

For the engine splash well drains to be below the waterline at static trim generally indicates that there is more weight in the stern of the boat than the original designer of the hull intended there to be. Your notion this added weight must be due to ingress of water into the foam interior of a Unibond hull is not a reasonable inference. The added weight could be from the engine, batteries, seats, or other gear added to the boat.

For advice on how to assess a hull for retained water, see the FAQ answer at

Q3: Is There Water in a Hull?
https://continuouswave.com/whaler/reference/FAQ/#Q3

Note that on some hulls the engine splash well is very deep, going down to the level of the keel, and there is a drain at the very bottom of the well. That drain will ALWAYS be below the water line, and if that drain is left open, there will always be water in the deep well bottom. On other hulls the engine splash well is not as deep, and the splash well drains will be very close to the water line when the boat is in proper trim at rest. For that type splash well, the drains would be just at the water line at static trim with an engine weight that was similar to the original engine weight from the era of the hulls original design.

A MONTAUK with a 115-HP is already over the hull's maximum power rating (100-HP). An engine of 100-HP from the era of the original hull design might have been an OMC V4, which would have weighed about 300-lbs. The OptiMax 115 weight is 75-lbs greater. With more engine weight there is an expectation that the static trim at the transom will have a higher waterline than the boat would have had with a lighter engine.

Re: Montauk 17: Waterline and Transom Drains

Posted: Sat Oct 02, 2021 3:13 pm
by Flynn
Thanks for the replies. I’m pulling the trigger and buying it Monday. The waterline when empty is halfway up the transom drains and the boat sits level in the water. Transom drains and anchor locker drain look to be in good shape as well. Removed a screw to shove a metal hanger down into the foam and it came out perfectly dry. Excited to get this boat home!