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construction and repairs, we look upon it as a serious mistake. There is no doubt -at all, in fact it has been known for a number of years, that a single-sheathed vessel, where the sheathing is fastened with bolts, and where copper is used to prevent corrosion, that the fastenings will soon corrode, eat away, and the planking become loose. To fasten the sheathing with brass composition leads to the thought at once that while you protect the bo'ts, you very soon com- mence to: destroy the frame of the ship, and I should not be surprised to have this gentleman write us a paper in the course of a few years describ- ing how the frame of this vessel has been almost entirely eaten away in the vicinity of the fastenings. The cure for this lies in an entirely different direction. The copper sheathing com- ing into the market now is not at all durable, and usually does not last on wooden vessels for more than two or three years, so the conclusion reached by those who have had experience with sheathing vessels is that the most economical plan is to fasten the sheathing with iron bolts, as hereto- fore, and put galvanized iron on the outside of the vessel instead of copper. Of course, we recognize galvanized iron is not as durable, and does not present as smooth a bottom as cop- per, but it will last for one or two years, and when the relative expense of repair and maintenance are taken into consideration, it is cheaper than copper sheathing of the character now received. RR, Row: terioration of iron and steel bolts, I remember about six or seven years ago I thad charge of a small ship yard, and we hauled a steel hull light vessel on the railway, and in the area of the skin connections, we found, in- stead of the plates chipping, that. the countersunk heads of the rivets had carbonized, and I remember an in- stance where I took a knife and cut them out, and the only thing by which we could account for that condition in that case was that, being in close proximity -to the. composition, they formed a galvanic action, owing to the high property of sulphur and _ phos- phorus in the rivets. Everything was intact on the inner portion of the ship, but outside of the skin of the ship we could just cut them out, and we drove between 700 and 800 rivets, but it did not affect the shell, and that was my reason for asking particularly what ef- fect it had on the real structure of the vessel in the area of the framing and tie-plates. iron. In speaking of the de-- THE Marine REVIEW Juius A. Furer: Relative to the comment about sheathing a vessel with galvanized iron, it is my understand- ing that these vessels are sheathed with composition move to prevent foul- ing than for any other purpose. Of course, in the casé of a light vessel, which is not under way ve:y much, some of them very little, it may not be very important to prevent fouling. But I understand that the gentleman re- ferred to the 'ordinary pzdetice of sheathing vessels, and I think it would be imteresting to hear as to the +e- sults obtained in preventing fouling by the use of galvanized ison. William McEntee: Apropos of the comments about the use of composi- tion 'bo:ts for securing the sheathing, there was an incident occurred at Mare island about thrée years ago which might be of some interest in that connection. The cruiser New Orleans was 'docked, and . she. is sheathed with teak, over the complete shell and all, about 3%-in. steel -plate, and I noticed on one of the plans in connection with some of the valves that the composition wool casting was shown connected direct to the steel plate of the interior. As I under- stand that to be bad practice, =f thought that the plan was out, and went down and examined it and found it true, that the composition casting which went through the sheathing was connected to the outer and inner beams directly to the steel plates. Finding this to be the case, I looked with much curiosity for corrosion, and found none around any of the com- position casting; some of the sheath- ing was also removed from the steel plate, underneath the steel plate, and found to be in excellent condition. William Hovgaard: I have no ex- perience in the use of galvanized iron for sheathing, but as is well known, zinc sheathing thas been so used in several cases, and the result was, I be- lieve, that it is not so effective as cop- per in preventing fouling. The effect of galvanized iron would, in this re- spect, of course, be the same, but I should think that the thin layer of zinc would soon be eaten away, and the iron then exposed to corrosion and fouling. W. J. Baxter: The question isnot one, as I understand it, of sheathing or not sheathing. This is a statement of certain results which have been pro- duced by a certain method of fasten- ing the ship. I happen to know that the frame of 'this particular ship was not injured in any way. It was quite true, that with this particular sheath- ing and composition bolts of one kind nection with this subject. Vs and another, the frames may dete- riorate, but when these frames dete- riotate, if the ship is pzoperly in- spected that deterioration can be seen, watched and remedied. With the gal- vanized fastening the deterioration goes on, it is impossible to see it, and a great disaster might result from a very small blow. When a ship's frame is fastened, or is not fastened, as we have seen from these figures, which are merely representative bolts, imag- ine what might occur should that ves- sel receive any shock in these waters. The merits of . various kinds of sheathing I will not attempt to speak of; I simply wanted to answer that one question about the results of the iron bolting on the steel frames, they were not touched at all, not injured at all. F, L. DuBosque: I feel cailed on to make a few further remarks in con- I know of cases that have come to my notice, and a great many of them, where the frames have been attacked, where iron bolts have been used to fasten the sheathing to the frames, and the rea- son of that is very apparent. [he galvanic action which is set up be- tween the copper outside the sheath- ing, and the nearest thing to it, at- tacks the first place it can, and the bolts give sufficient material to be at- tacked until they are entirely eaten away. In reply to Mr. Baxter, I 'would say that this matter comes closer to my attention today, because I have on my desk a number of samples of 'bolts taken out of a sheathed vessel a few days ago. Some of these bolts are in two .parts, they are so thoroughly eaten away that the head had separ- ated from the shank, and my first sur- prise was that the sheathing remained on this boat at all Ihe answer to that seems to be that here and there through the planking there seems 'to be enough fastening to hold the plank- ing to its shape and the calking ot the planking does the rest. In this particular case the vessel was subject to more shock than any naval vessel would be called upon to endure, be- cause this ship is used in towing service 10 hours out of the 24 every day, bumping up against the sides of heavy craft which she was towing. I make no claim for the durability of galvanized iron sheathing, but I claim it is the least expensive of the two kinds, very much less expensive than copper. It is quite as durable as zinc sheathing, for zinc sheathing will last no longer on the bottom of a boat than galvanized iron, as we know